Open Source Tips

Superb Spring Info

2012-01-23T18:50:00.000-08:00

Superb Spring blog http://www.baeldung.com/

Simplifying the Data Access Layer

Movie Theater Engagement Database

2012-01-01T13:52:00.000-08:00

This is a similar database to that one created yesterday but may clarify some of the design decisions. By naming the JOIN table 'Engagement', I think its purpose is clearer than the JOIN table in the Recipes database, 'RecipeIngredient'.

MySQL Database for Cookbook

2011-12-31T22:44:00.000-08:00

Today I saw a good Ruby on Rails video that addressed a similar problem.

Spring Persistence with Hibernate

2011-12-27T20:31:00.000-08:00

The book "Spring Persistence with Hibernate" is a little hard to follow so I diagrammed a bit of the code:

StreamReaderHelper.java

2011-12-26T10:48:00.000-08:00

I was using Apache HTTPComponents and needed to get the content from the response InputStream. It seemed like a lot of code and thus, needed a test.

Test Using Apache HTTPComponents

2011-12-21T20:42:00.000-08:00

My project has a servlet that does nothing more than call a stored procedure and return the results returned from the stored procedure. It requires a different kind of test. I enjoyed working with HTTPComponents even if the test is not yet all I want it to be. This first version only tests to ensure the HTTP request can be completed. :(

Ruby Hash

2011-12-19T20:25:00.001-08:00

and using the CodeRunner app is pretty cool . . .

Uniform Level of Abstraction

2011-12-17T13:20:00.000-08:00

Glenn Vanderburg's presentation, Tactical Design

Very good stuff.

Mockito

2011-12-13T15:41:00.000-08:00

I created a tiny project with which to quickly refresh my memory of Mockito. Knowing I would blog this code, I made the classes as concise as possible.

[Programmable_with_Mockito] ant
Buildfile: /Users/javapro/dev/src/java/Programmable_with_Mockito/build.xml

clean:
   [delete] Deleting directory /Users/javapro/dev/src/java/Programmable_with_Mockito/bin

init:
    [mkdir] Created dir: /Users/javapro/dev/src/java/Programmable_with_Mockito/bin

compile:
    [javac] Compiling 3 source files to /Users/javapro/dev/src/java/Programmable_with_Mockito/bin
    [javac] Note: /Users/javapro/dev/src/java/Programmable_with_Mockito/src/us/home/electronics/ProgrammableTest.java uses or overrides a deprecated API.
    [javac] Note: Recompile with -Xlint:deprecation for details.

test:
    [junit] Running us.home.electronics.ProgrammableTest
    [junit] Testsuite: us.home.electronics.ProgrammableTest
    [junit] Tests run: 1, Failures: 0, Errors: 0, Time elapsed: 0.312 sec
    [junit] Tests run: 1, Failures: 0, Errors: 0, Time elapsed: 0.312 sec
    [junit] 
    [junit] Testcase: testBeepBeep took 0.276 sec

BUILD SUCCESSFUL
Total time: 1 second
[Programmable_with_Mockito]

2011-12-07T14:46:00.000-08:00

Not sure why this is so great ...

Want an IRB console in any maven project? Try "mvn org.jruby.plugins:jruby-rake-plugin:irb". No need to modify POM!

Processing.js Horror

2011-12-01T04:28:00.000-08:00

Processing.js reminds me of RPG code. The fill() function in the code below is a mystery. fill() offers no hint of what context the fill is to apply to.

if(count <= 90) {
      letter = char(65+counter);
      if(letter == 'A' || letter == 'E' || letter == 'I' || 
         letter == 'O' || letter == 'U') {
           fill(204, 204, 0);
      } else {
        fill(255);
      }
    } else {
      fill(153);
      letter = char(48+counter);
    }

By running the code, one can see that the fill does indeed apply to the letter. It appears that fill() can be called either before or after the letter is created but who can be sure? In this code, a letter is created and the fill is defined but we never see how the two are brought together. Object oriented development avoids this problem.

Beginner's Mind

2011-11-30T19:43:00.000-08:00

Matthew McCullough gave an excellent talk this evening at Rich Web Experience. Reviewing Matt's slides from another talk, I found a great quote:

In the beginner's mind, there are many possibilities.  In the expert's mind, there are few.

Two Lists

2011-11-25T05:55:00.000-08:00

Long time ago, I memorized 2 lists of 4 items each

Objects have identity, lifetime, state and behavior. Object oriented development utilizes inheritance, polymorphism, encapsulation and abstraction.

jQuery Selectors

2011-11-24T19:46:00.000-08:00

Javascript - One Image, Two Buttons

2011-11-23T13:32:00.000-08:00

Downloading one image instead of several is one way to optimize web performance. This code shows how to use different portions of the image at various points in the page.

<html>
    <head>
         <style type="text/css">
            .button-up {
                position: absolute;
                clip: rect(215px 49px 270px 0);
            }
            .button-down {
                position: absolute;
                clip: rect(0 49px 50px 0);
            }
        </style>

    </head>
    <body>
        <div id="content">
                <span id="upButton" style="position:absolute;top:-215;left:200;width:50px;height:50px;">
                    <img src="UpAndDownButtons.jpg" class="button-up" onclick="pressButton('upButton', 'downButton')"/>
                </span>
                <span id="downButton" style="position:absolute;top:2;left:200;width:50px;height:50px;">
                    <img src="UpAndDownButtons.jpg" class="button-down" onclick="pressButton('downButton', 'upButton')"/>
                </span>
        </div>
        <script type="text/javascript">

            function pressButton(fromButton, toButton) {
                var from = document.getElementById(fromButton);
                from.style.display = "none";

                var to = document.getElementById(toButton);
                to.style.display = "block";
            }

            function initPage() {
                var up = document.getElementById("upButton");
                up.style.display = "block";
                var down = document.getElementById("downButton");
                down.style.display = "none";
            }

            initPage();
        </script>
    </body>
</html>

Clojure Lists, Maps and Sets

2011-11-13T16:10:00.000-08:00

Define the unless function on the first line of 'unless.clj' and then, use it in a few expressions:

[clojure] java -cp .:$CLOJURE_HOME/clojure-1.3.0.jar:$CLOJURE_HOME/jline-1.0.jar jline.ConsoleRunner clojure.main
Clojure 1.3.0
user=> (load-file "unless.clj")
nil
"it's good to be 12"
"6 it's good to be 6"
"5 "
nil
user=>

I found out about transactional Clojure in the book Practical Clojure by Luke VanderHart:

user=> (load-file "dosync.clj")
b
c
d
nil
user=>

Often, single data items don't require names because they are stored in a list, map or set and can be worked on in sequence. In this example, three accounts are stored in the account-info datastructure.

Another test of a loop-thru function coded in loop-thru-maps.clj:

user=> (load-file "loop-thru-maps.clj")
{:balance 11.59, :member-since "2009-22-02", :username "jak"}
{:balance 13.59, :member-since "2009-02-01", :username "zak"}
{:balance 12.59, :member-since "2011-02-02", :username "mak"}
clojure.lang.PersistentHashMap
{:balance 11.59, :member-since "2009-22-02", :username "jak"}
{:balance 13.59, :member-since "2009-02-01", :username "zak"}
{:balance 12.59, :member-since "2011-02-02", :username "mak"}
nil
user=>

Old School JDBC-ODBC

2011-11-10T17:30:00.000-08:00

I think I did this once 12 years ago but today I wanted to test the accessibility of a SQL Server 6.5 database. After creating a ODBC datasource in Windows for the remote database, the following code ran perfectly. Recall that the JdbcOdbcServer.class is included in rt.jar so it is available without listing any jar in the classpath.

This proved to me that the database was not the issue causing the Windows 95 application to fail.

Postgresql Server Management

2011-11-06T07:07:00.000-08:00

[pgsql-9.0] cd bin
[bin] cd /usr/local/pgsql-9.0/bin
[bin] initdb /Users/javapro/dev/database/postgres_data/petstore
The files belonging to this database system will be owned by user "javapro".
This user must also own the server process.
. . . 
Success. You can now start the database server using:

    postgres -D /Users/javapro/dev/database/postgres_data/petstore
or
    pg_ctl -D /Users/javapro/dev/database/postgres_data/petstore -l logfile start

[bin] pg_ctl -D /Users/javapro/dev/database/postgres_data/petstore -l logfile start
server starting

Manage the server using other options of pg_ctl

pg_ctl start [-w] [-t seconds] [-s] [-D datadir] [-l filename] [-o options] [-p path] [-c]
pg_ctl stop [-W] [-t seconds] [-s] [-D datadir] [-m s[mart] | f[ast] | i[mmediate] ]
pg_ctl restart [-w] [-t seconds] [-s] [-D datadir] [-c] [-m s[mart] | f[ast] | i[mmediate] ] [-o options]
pg_ctl reload [-s] [-D datadir]
pg_ctl status [-D datadir]
pg_ctl kill signal_name process_id
pg_ctl register [-N servicename] [-U username] [-P password] [-D datadir] [-w] [-t seconds] [-s] [-o options]
pg_ctl unregister [-N servicename]

Clojure recursion and recur

2011-10-24T01:53:00.000-07:00

I'm still trying to find good explanations of this stuff but for now, trial and error provides results.

(defn loopthru1 [n]
  (if-not (empty? n) (do
       (println (first n))
       (loopthru1 (rest n))
  ))
)
(loopthru1 [1 2 3 4 5 6])

(def pack
  [ { :name "Bichon Frise"
      :description (list "small" "white" "even-tempered")}
    { :name "Australian Shepherd"
      :description (list "medium" "mottled" "even-tempered")}
  ])
(loopthru1 pack)

loopthru 1 (above) explicitly calls itself whereas loopthru2 (below) uses recur.

(defn loopthru2 [n]
  (if-not (empty? n)
    (do (println (first n))
     (recur (rest n)))))
(loopthru2 [1 2 3 4 5 6])

(defn loopthru3 [n]
  (when (seq n)
    (println (first n))
    (recur (rest n))))
(loopthru3 [1 2 3 4 5 6])

Top 10 Vulnerabilities

2011-10-15T11:02:00.000-07:00

OWASP, Open Web Application Security Project, identifies risks and provides tutorials showing how to protect against the threats.

https://www.owasp.org/index.php/Top_10_2010-Main

Baseball Chat

2011-09-27T20:10:00.000-07:00

I'm using MAMP and liking it.

styles.css

body {
    background-image: url('../images/background.png');
    font-family: Helvetica, Arial, sans-serif;
    font-size: 10pt;
    color: white;
    margin-top: 10px;
}

.messagePanel {
    position: absolute;
    top: 95px;
    left: 420px;
    padding: 15px 15px 15px 15px;
    color: black;
}

.inputPanel {
    overflow: auto;
    background: white;
    padding: 10px 10px 10px 10px;
    margin-bottom: 10px;
    border-radius: 10px;
    -moz-border-radius: 10px;
}

.outputPanel {
    background: white;
    height: 317px;
    width: 528px;
    overflow: auto;
    padding: 15px 15px 15px 15px;
    -moz-border-radius: 10px;
}

.buttonBar {
    position: absolute;
    top: 65px;
    left: 15px;
}

.roster {
    background: white;
    color: black;
}

chat.html

<!DOCTYPE html>
<html>
  <head>
      <title>Let's Go BlueSox!</title>
      <meta http-equiv="content-type" content="text/html; charset=utf-8">
      <link href='stylesheets/styles.css' rel='stylesheet' type='text/css' />
      <script src="http://ajax.googleapis.com/ajax/libs/jquery/1.5/jquery.min.js"></script>
  </head>
  <body>
 
      <img src='images/logo_990x80.png' width='990' height='80' />
      <p>Loading ...</p>

      <div class='messagePanel'>
          <div id='messages' class='inputPanel'>
              <input type='text' id='author' placeholder='Name' size='10'/>
              <input type='text' id='contents' placeholder='Your Message' size='57'/>
              <input type='button' id='sendButton' value='Send'/>
          </div>
          <div class='outputPanel'>
              <div id='roster' class='panel'></div>
          </div>
      </div>

      <script type="text/javascript">

      $(document).ready(function() {
          $('p').text('Ready');

          $('#sendButton').click(function() { 
              sendMessage();
          });
            
          var sendMessage = function() {
              var author = $('#author').val();
              var contents = $('#contents').val();
          
              var data = "author=" + escape(author) + "&contents=" + escape(contents);
           
              if (author != '' && contents != '') {
                  $('#roster').append( author + ':' + contents + '<br/>');
                
                  $('#contents').val("");
                  $('#contents').focus();
    
                  $('p').text('Sending');

                  $.ajax({
                      type: 'POST',
                      url: 'post_message.php',
                      data: data,
                      success: $('p').text('Success')
                  });
              }
          }
      });
      </script>

    </body>
</html>

post_message.php

<?php
    $link = mysql_connect('localhost','root','root') or die('Cannot connect to the DB');
    mysql_select_db('ChatterDB',$link) or die('Cannot select the DB');

    $author = $_POST["author"];
    $contents = $_POST["contents"];

    $sql='INSERT INTO messages (author, contents)
    VALUES
    ("' . $author . '","' . $contents . '")';
    
    if (!mysql_query($sql,$link)) {
        die('Error: ' . mysql_error());
    }
    
    mysql_close($link);
    
    //sleep(5);
?>

To use MAMP's MySQL from the command line, use the following command:

[~] /Applications/MAMP/Library/bin/mysql -u root --password=root
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 53
Server version: 5.5.9 Source distribution

Copyright (c) 2000, 2010, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| ChatterDB          |
| mysql              |
| performance_schema |
+--------------------+
4 rows in set (0.03 sec)

mysql>

Motivation

2011-07-24T13:19:00.001-07:00

TED Talk on Motivation

Maven Archetypes on Webtide

2011-07-22T04:33:00.000-07:00

Webtide's Archetypes

First Evidence

2011-07-18T18:07:00.000-07:00

Elah Valley, Israel (CNN) -- Archaeologists in Israel have found remains which may be the biblical City of King David, the first evidence that the ancient Jewish empire actually existed. The bible refers to a powerful 10th century B.C. Kingdom of David, Israel's second king, stretching from Egypt to the Euphrates, but little evidence of its existence has ever been found.

Now, an archaeological discovery at Khirbet Qeiyafa, in Elah Valley, 30 km from Jerusalem, appears to show signs of a Jewish settlement. Professor Yosef Garfinkel ... added: "We do have animal bones. Thousands of animal bones were on site. We have sheep, cattle and goats. But we have no pigs at all. In Canaanite and Philistine cities you will find up to 20% pig bones."

Neanderthals

2011-07-18T17:54:00.000-07:00

ScienceDaily (July 17, 2011) —
Some of the human X chromosome originates from Neanderthals and is found exclusively in people outside Africa, according to an international team of researchers led by Damian Labuda of the Department of Pediatrics at the University of Montreal and the CHU Sainte-Justine Research Center. The research was published in the July issue of Molecular Biology and Evolution.

CoffeeScript

2011-06-14T14:57:00.000-07:00

CoffeeScript, the Ruby of JavaScript. This first line calls parseRawDescription, passing one argument which is one string with two values concatenated. The second block is the function definition.

[all, @title, @price] = @parseRawDescription rawDescription

parseRawDescription: (rawDescription) ->
    pattern = ///
        ([^$]+)         #title 
        (\$\d+\.\d+)    #price
    ///
    result = rawDescription.match pattern 
    r.trim() for r in result

JavaScript Web Applications

2011-05-31T18:44:00.000-07:00

O'Reilly offers early access to the book "JavaScript Web Applications" by Alex MacCaw. Final release is September 2011. A portion of O'Reilly's description of the book follows:

Building rich JavaScript applications that bring the desktop experience to the Web is now possible, thanks to powerful JavaScript engines and the CSS3 and HTML5 specifications. The key is moving state from the server to the client side; but that's no simple task.... Explore MVC and how to best structure and manage dependencies inside your application. Get an introduction to templating and data binding....

This is extremely compelling.

Violet UML Editor

2011-05-23T19:12:00.000-07:00

Download Violet UML editor from sourceforge.

Design decisions made in the development of Violet.

Why Does This Work?

2011-05-20T19:53:00.001-07:00

class Person {
    def name
    def age
}

jill = new Person(name: 'Jill', age: 21) 
john = new Person(name: 'John', age: 12)
jorge = [name: "Jorge", age: 3]

def printPerson(x) {
    println "This is ${x.name} who is ${x.age}"
}

printPerson(jill)
printPerson(john)
printPerson(jorge)

This is Jill who is 21
This is John who is 12
This is Jorge who is 3

Now, a slightly different version shows the accessor is called implicitly when using the field name

class Person {
    def name
    def age
    
    String getName() {
        return "Calling the accessor ..."
    }
}

jill = new Person(name: 'Jill', age: 21) 
john = new Person(name: 'John', age: 12)
jorge = [name: "Jorge", age: 3]

def printPerson(x) {
    println "This is ${x.name} who is ${x.age}"
}

printPerson(jill)
printPerson(john)
printPerson(jorge)

This is Calling the accessor ... who is 21
This is Calling the accessor ... who is 12
This is Jorge who is 3

When the groovy code is compiled and javap run on the class, I find that there is no getName() method. There is however, a getProperty(java.lang.String) method that returns an object. Going out on a limb, I'm guessing that getProperty is called with the field name passed to it, something like java.util.Calendar.get(java.util.Calendar.DAY_OF_MONTH).

Manning's New Book - Entity Framework 4 in Action

2011-05-18T21:56:00.000-07:00

Quote from the book -
In the Java world, a structure like the dataset has always existed, but its use is now discouraged except for the simplest applications. In the .NET world, we’re facing the beginning of this trend too.

60 Minutes

2011-05-17T16:40:00.000-07:00

In his interview on Sunday's 60 Minutes, Robert Gates said his greatest frustration was that he lead a department that is organized to plan for war but not to fight a war.

Today at Rails Conf 2011, Eric Ries, the creator of the Lean Startup methodology and the author of the popular entrepreneurship blog Startup Lessons Learned, noted that waterfall methodology is similar in that waterfall is great for creating a plan for the development of a really bad product.

SQLite and ANT

2011-05-15T08:07:00.000-07:00

The targets that can be run are:

$ ant sqlcreate
$ ant sqlschema
$ ant sqlpopulate
$ ant sqlselect
$ ant sqldrop

The SQLSCHEMA target in the ANT file displays the tables in an SQLite database with this command:

sqlite> SELECT name FROM sqlite_master WHERE type='table';

Other Common Commands

sqlite> .tables
sqlite> .schema [TABLE] (such as Customers table)
sqlite> explain [SQL COMMAND] 
sqlite> .separator [CHARACTER] (such as comma or vertical bar)
sqlite> .databases
sqlite> .read [FILENAME]

Termination Commands to terminate a line

semicolon ;
GO
forward slash /

Geronimo Server

2011-05-08T09:53:00.000-07:00

I was very happy to see that Geronimo works with Jetty. I downloaded the archive and extracted the app then started the console.

[greg:bin] ./geronimo run
Using GERONIMO_HOME:   /Users/javapro/dev/bin/geronimo-jetty8
Using GERONIMO_TMPDIR: var/temp
Using JRE_HOME:        /System/Library/Frameworks/JavaVM.framework/Versions/1.6/Home
                                                          
     ______                       _                       
    / ____/___  _________  ____  (_)____ ___  ____        
   / / __ / _ \/ ___/ __ \/ __ \/ // __ `__ \/ __ \  
  / /_/ //  __/ /  / /_/ / / / / // / / / / / /_/ /       
  \____/ \___/_/   \____/_/ /_/_//_/ /_/ /_/\____/    

  Apache Geronimo (3.0-M1)

Hit '' for a list of available commands
and '[cmd] --help' for help on a specific command.
Hit '' or 'osgi:shutdown' to shutdown Geronimo.

geronimo> Booting Geronimo Kernel (in Java 1.6.0_24)...
. . .

I downloaded the example so I could verify the installation. In another command window, I entered the command to deploy the WAR file.

[greg:geronimo-jetty8] cd bin
[greg:bin] ./deploy --user system --password manager deploy ~/dev/bin/HelloWorld.war
Using GERONIMO_HOME:   /Users/javapro/dev/bin/geronimo-jetty8
Using GERONIMO_TMPDIR: var/temp
Using JRE_HOME:        /System/Library/Frameworks/JavaVM.framework/Versions/1.6/Home
    Deployed org.apache.geronimo.samples/HelloWorldApp/1.0/war @ /hello
[greg:bin]

Now for the EJB project described in the Better Builds with Maven guide.

[greg:java] svn co http://svn.apache.org/repos/asf/geronimo/daytrader/trunk/ 
. . . 
 U   trunk
Checked out revision 1100785.
[greg:java] mv trunk daytrader
[greg:java] cd daytrader

Trader Joe’s

2011-05-03T19:49:00.001-07:00

Trader Joe’s will open several locations in the Dallas area by the end of 2011.

Who Makes This Stuff Up?

2011-05-01T12:12:00.001-07:00

A Little Python

2011-04-30T13:47:00.000-07:00

class Hello():
 
 def __init__(self):
  self.nbrTimes = 5
  
 def sayHello(self):
  for x in range(self.nbrTimes):
   print('Hello')
   
hello = Hello()
hello.sayHello()

An Engineer

2011-04-01T17:06:00.001-07:00

An engineer is a person who can do for a dime what any fool can do for a dollar.

Tapestry 5

2011-03-25T22:16:00.000-07:00

The directions on this page are no good.

These did work.

My Opinion

2011-03-25T21:06:00.000-07:00

Programming, it turns out, is hard. Eloquent Javascript by Marijn Haverbeke

My opinion: Programming, it turns out, is not difficult but, it does take effort.

With Bitnami stacks, that effort required to create a Java Web development environment is greatly reduced.

It includes ready-to-run versions of Apache, Tomcat, MySQL and Java and required dependencies. The process is simple - just download, click next-next-next and you are done! It is completely self contained and will not interfere with other software on your system.

Download from here: http://bitnami.org/stack/tomcatstack

Naked Objects

2011-03-08T04:04:00.000-08:00

Naked Objects in Ruby by Glenn Vanderburg. Must see TV!

Glenn's presentation of DSLs in Ruby

Glenn's The Power of Javascript presentation.

Glenn's Tactical Design presentation.

DeMarco

2011-02-19T20:36:00.000-08:00

Kent Beck and Venkat Subramaniam are tweeting about how great Tom DeMarco's mea culpa is.

DeMarco says "software engineering is an idea whose time has come and gone" and explains that the specific practices that are understood to be what the term 'software engineering' means have little value when exercised in the common contexts in which software is developed today.

Glenn Vanderburg gave an excellent presentation in which he spoke for more than an hour about the evolution of 'software engineering' and never mentioned DeMarco.

Using Homebrew to Install Postgresql

2011-02-19T17:00:00.000-08:00

[greg:local] brew install postgresql
==> Downloading ftp://ftp.ossp.org/pkg/lib/uuid/uuid-1.6.2.tar.gz
######################################################################## 100.0%
. . . <<many lines logged from the install process>>
Success. You can now start the database server using:

    postgres -D /usr/local/var/pg_data
or
    pg_ctl -D /usr/local/var/pg_data -l logfile start

[greg:local] pg_ctl -D /usr/local/var/pg_data -l /tmp/logfile start
[greg:local] createdb test
[greg:local] psql test
psql (9.0.3)
Type "help" for help.

test=# CREATE TABLE authors (id INT PRIMARY KEY, name VARCHAR);
NOTICE:  CREATE TABLE / PRIMARY KEY will create implicit index "authors_pkey" for table "authors"
CREATE TABLE
test=# CREATE TABLE books (id INT PRIMARY KEY, title VARCHAR, pages INT);
NOTICE:  CREATE TABLE / PRIMARY KEY will create implicit index "book_pkey" for table "book"
CREATE TABLE
test=# CREATE TABLE booksauthors (book_id INT, author_id INT);
CREATE TABLE
test=# INSERT INTO authors VALUES (1, 'Craig Walls');
INSERT 0 1
test=# INSERT INTO authors VALUES (2, 'Ryan Breidenbach');
INSERT 0 1
test=# CREATE TABLE booksauthors (book_id INT REFERENCES books(id), author_id INT REFERENCES authors(id));
CREATE TABLE
test=# INSERT INTO booksauthors VALUES (1,1), (1,2);
INSERT 0 2
test=# SELECT books.title, authors.name FROM books JOIN booksauthors ON books.id = booksauthors.book_id 
JOIN authors ON authors.id = booksauthors.author_id;
      title       |       name       
------------------+------------------
 Spring in Action | Craig Walls
 Spring in Action | Ryan Breidenbach
(2 rows)

test=#
\q
[greg:rails] rails new rails_and_pg --database postgresql
[greg:rails] cd rails_and_pg
[greg:rails_and_pg] mate .
[greg:rails_and_pg] bundle install
[greg:rails_and_pg] rake db:create:all

Starting and stopping Postgresql can be accomplished with these scripts:

[greg:rails_and_pg] sudo launchctl load /Library/LaunchDaemons/org.postgresql.postgres.plist
Password:
org.postgresql.postgres: Already loaded
[greg:rails_and_pg] sudo launchctl unload /Library/LaunchDaemons/org.postgresql.postgres.plist

After installing the PROJ and GEOS frameworks, PostGIS can be installed on Postgresql. These are available from this site.

Then, to start PostGIS:

psql -d postgres -U postgres

IN-N-OUT Burger Coming Soon to Frisco TX

2011-02-05T20:54:00.000-08:00

2800 Preston Rd.
Frisco, TX 75034

SOLID Ruby

2011-02-05T18:42:00.000-08:00

Sandi Metz's presentation of Bob Martin's SOLID design principles for Ruby developers and her slides.

Sandi used DI to setup her opportunity to mock the downloader.

class PatentJOB 
  attr_reader :downloader

  def initialize(downloader = PatentDownloader.new)
    @downloader = downloader
  end

  def run 
    temp = downloader.download_file
  end
end

require 'tempfile'
class PatentDownloader
  def download_file 
    temp = Tempfile.new('patents')
    tempname = temp.path
    temp.close

    Net::FTP.open('localhost', 'foo', 'foopw') do |ftp|
      ftp.getbinaryfile('Public/prod/patents.csv', tempname)
    end
    tempname
  end 
end

And she provides this YAML and a class that uses that YAML to create

defaults: &defaults 
  ftp_host:      localhost
  ftp_login:     foo
  ftp_password   foopw
  ftp_filename:  patents.csv
  ftp_path:      Public/test

test: 
  <<: *defaults

development:
  <<: *defaults

production:
  ftp_path:     Public/prod
  <<: *defaults

class Config 
  attr_reader :data :env
  def self.config_path 
    file.join('config', 'external_resources')
  end

  def initialize(opts) 

  end 

  def define_methods_for_environment(names) 
    names.each do |name| 
      class_eval <<-EOS
        def #{name} 
          data[env]['#(name)']
        end
        EOS 
      end
    end
  end

And this allows us to refactor to more a loosely coupled design:

require 'tempfile'
class PatentDownloader 
  attr_reader :config
  
  def initialize(config=Config.new(:filename => 'patent.yaml'))
    @config = config
  end

  def download_file
    temp = Tempfile.new(config.ftp_filename)
    tempname = temp.path
    temp.close

    Net::FTP.open(config.ftp_host, config.ftp_login, config.ftp_password) do |ftp|
      ftp.getbinaryfile(config.ftp_path, tempname)
    end
    tempname
  end
end

Hello JSF

2011-02-05T16:29:00.000-08:00

I'll try to create a Hello World project using Maven 3 and JSF.

[greg:mvnsrc] mvn archetype:generate -DarchetypeCatalog=http://myfaces.apache.org
[INFO] Scanning for projects...
[INFO]                                                                         
[INFO] ------------------------------------------------------------------------
[INFO] Building Maven Stub Project (No POM) 1
[INFO] ------------------------------------------------------------------------
[INFO] 
[INFO] >>> maven-archetype-plugin:2.0:generate (default-cli) @ standalone-pom >>>
[INFO] 
[INFO] <<< maven-archetype-plugin:2.0:generate (default-cli) @ standalone-pom <<<
[INFO] 
[INFO] --- maven-archetype-plugin:2.0:generate (default-cli) @ standalone-pom ---
[INFO] Generating project in Interactive mode
[INFO] No archetype defined. Using maven-archetype-quickstart (org.apache.maven.archetypes:maven-archetype-quickstart:1.0)
Choose archetype:
1: http://myfaces.apache.org -> myfaces-archetype-helloworld (myfaces-archetype-helloworld)
2: http://myfaces.apache.org -> myfaces-archetype-helloworld-facelets (myfaces-archetype-helloworld-facelets)
3: http://myfaces.apache.org -> myfaces-archetype-helloworld-portlets (myfaces-archetype-helloworld-portlets)
4: http://myfaces.apache.org -> myfaces-archetype-helloworld20 (myfaces-archetype-helloworld20)
5: http://myfaces.apache.org -> myfaces-archetype-helloworld20-owb (myfaces-archetype-helloworld20-owb)
6: http://myfaces.apache.org -> myfaces-archetype-jsfcomponents (myfaces-archetype-jsfcomponents)
7: http://myfaces.apache.org -> myfaces-archetype-trinidad (myfaces-archetype-trinidad)
8: http://myfaces.apache.org -> myfaces-archetype-trinidad20 (myfaces-archetype-trinidad20)
Choose a number: : 1
Downloading: http://myfaces.apache.org/org/apache/myfaces/buildtools/myfaces-archetype-helloworld/1.0.2/myfaces-archetype-helloworld-1.0.2.jar
Downloading: http://repo1.maven.org/maven2/org/apache/myfaces/buildtools/myfaces-archetype-helloworld/1.0.2/myfaces-archetype-helloworld-1.0.2.jar
Downloaded: http://repo1.maven.org/maven2/org/apache/myfaces/buildtools/myfaces-archetype-helloworld/1.0.2/myfaces-archetype-helloworld-1.0.2.jar
Downloading: http://myfaces.apache.org/org/apache/myfaces/buildtools/myfaces-archetype-helloworld/1.0.2/myfaces-archetype-helloworld-1.0.2.pom
Downloading: http://repo1.maven.org/maven2/org/apache/myfaces/buildtools/myfaces-archetype-helloworld/1.0.2/myfaces-archetype-helloworld-1.0.2.pom
Downloaded: http://repo1.maven.org/maven2/org/apache/myfaces/buildtools/myfaces-archetype-helloworld/1.0.2/myfaces-archetype-helloworld-1.0.2.pom
Define value for property 'groupId': : org.greg.helloworld
Define value for property 'artifactId': : firstJSF
Define value for property 'version':  1.0-SNAPSHOT: : 1.0
Define value for property 'package':  org.greg.helloworld: : 
Confirm properties configuration:
groupId: org.greg.helloworld
artifactId: firstJSF
version: 1.0
package: org.greg.helloworld
 Y: : 
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 2:34.604s
[INFO] Finished at: Sat Feb 05 17:59:28 CST 2011
[INFO] Final Memory: 9M/81M
[INFO] ------------------------------------------------------------------------
[greg:mvnsrc] cd firstJSF
[greg:firstJSF] mvn clean package jetty:run -Djetty.port=8181
[greg:firstjsf] open http://localhost:8181/firstJSF
[greg:firstjsf]

C++ Cookbook

2011-01-30T17:25:00.000-08:00

I used the commands below to compile the first exercise in O'Reilly's C++ Cookbook. The book provides the commands to compile and link for several different compilers. I had difficulty finding the command to link to the dynamic library when creating the executable. To compile a module with dependencies on the newly created dynamic library, use the highlighted command below.

libjohnpaul.a is statically linked. libgeorgeringo.dylib is dynamically linked. In order for hellobeatles to run, libgeorgeringo.dylib must be copied into the same folder as the hellobeatles executable.

[greg:johnpaul] g++ -c -o john.o john.cpp
[greg:johnpaul] g++ -c -o paul.o paul.cpp
[greg:johnpaul] g++ -c -o johnpaul.o johnpaul.cpp
[greg:johnpaul] ar ru libjohnpaul.a john.o paul.o johnpaul.o
[greg:johnpaul] ranlib libjohnpaul.a
[greg:johnpaul] cd ../georgeringo
[greg:georgeringo] g++ -c -o george.o george.cpp
[greg:georgeringo] g++ -c -o ringo.o ringo.cpp
[greg:georgeringo] g++ -c -o georgeringo.o georgeringo.cpp
[greg:georgeringo] g++ -dynamiclib -fPIC -o libgeorgeringo.dylib george.o ringo.o georgeringo.o
[greg:georgeringo] cd ../hellobeatles
[greg:hellobeatles] g++ -c -I.. -o hellobeatles.o hellobeatles.cpp
[greg:hellobeatles] g++ -o hellobeatles hellobeatles.o -L../johnpaul -L../georgeringo -ljohnpaul -lgeorgeringo
[greg:hellobeatles] cp ../georgeringo/libgeorgeringo.dylib libgeorgeringo.dylib
[greg:hellobeatles] ./hellobeatles
John, Paul, George, and Ringo
[greg:hellobeatles]

The book, including the source for each Beatle, can be found online. The online version has some significant differences with the PDF available from O'Reilly.

Code Metrics

2010-11-17T17:52:00.000-08:00

Transformative aspects of the technical debt metric.

Scala in Stalled

2010-11-15T18:53:00.000-08:00

A play on the Scala in Action title of the Manning book. :)

I have started using Homebrew and it is pretty close to perfect. The Scala install is the first issue I've had.

[greg:local] brew install scala
==> Downloading http://www.scala-lang.org/downloads/distrib/files/scala-2.8.1.final.tgz
######################################################################## 100.0%
/usr/local/Cellar/scala/2.8.1: 113 files, 22M, built in 2 seconds
[greg:local] scala
-bash: /opt/scala-2.7.5.final/bin/scala: No such file or directory
[greg:local] sudo scala
Password:
Welcome to Scala version 2.8.1.final (Java HotSpot(TM) 64-Bit Server VM, Java 1.6.0_22).
Type in expressions to have them evaluated.
Type :help for more information.

scala> 1 + 2
res0: Int = 3

scala>

Now we know what makes it work and how to correct the issue:

[greg:local] chmod 755 /usr/local/Cellar/scala/2.8.1/bin/*
[greg:local] scala
Welcome to Scala version 2.8.1.final (Java HotSpot(TM) 64-Bit Server VM, Java 1.6.0_22).
Type in expressions to have them evaluated.
Type :help for more information.

scala> 1 + 9
res0: Int = 10

scala> val myList = new java.util.ArrayList[String]()
myList: java.util.ArrayList[String] = []

scala> myList.add("Hello") 
res1: Boolean = true

scala> myList.add("World")
res2: Boolean = true

scala> myList
res3: java.util.ArrayList[String] = [Hello, World]

scala> myList.<TAB>

add              addAll           asInstanceOf     clear            clone            contains
containsAll      ensureCapacity   get              indexOf          isEmpty          isInstanceOf
iterator         lastIndexOf      listIterator     remove           removeAll        retainAll
set              size             subList          toArray          toString         trimToSize

scala> 1.<TAB>     

%              &              *              +              -              /              >
>=             >>             >>>            ^              asInstanceOf   isInstanceOf   toByte
toChar         toDouble       toFloat        toInt          toLong         toShort        toString
unary_+        unary_-        unary_~        |

scala> 1.

Enter the name of a variable and the dot operator and press TAB to list the object's methods.

Remember Jython?

2010-11-14T15:11:00.000-08:00

TestClass.java

import org.python.util.PythonInterpreter;
import org.python.core.*;

public class TestClass {

 public static void main(String[] args) {
  try {
   PythonInterpreter py = new PythonInterpreter(); 
   py.execfile(args[0]);
  } catch(Exception e) {
   e.printStackTrace();
  }
 }
}

mypy.py

print 'Hello, World'

Terminal

[greg:py] javac -cp .:${HOME}/dev/bin/jython2.5.2/jython.jar TestClass.java
[greg:py] java -cp .:/${HOME}/dev/bin/jython2.5.2/jython.jar TestClass mypy.py
Hello, World
[greg:py]

Interactive Swing

Create a Swing UI Without Compiling

[greg:local] jython
Jython 2.5.1 (Release_2_5_1:6813, Sep 26 2009, 13:47:54) 
[Java HotSpot(TM) 64-Bit Server VM (Apple Inc.)] on java1.6.0_22
Type "help", "copyright", "credits" or "license" for more information.
>>> print 'Hello, World'              
Hello, World
>>> from javax.swing import JButton, JFrame
>>> frame = JFrame('Hello Jython', defaultCloseOperation = JFrame.EXIT_ON_CLOSE, size=(300,300))
>>> def change_text(event):
...    print 'Clicked!'
... 
>>> button = JButton('Click Me', actionPerformed = change_text) 
>>> frame.add(button)
javax.swing.JButton[,0,0,0x0,invalid,alignmentX=0.0,alignmentY=0.5,border=com.apple.laf.AquaButtonBorder$Dynamic@32a6faa9,
flags=288,maximumSize=,minimumSize=,preferredSize=,defaultIcon=,disabledIcon=,disabledSelectedIcon=,
margin=javax.swing.plaf.InsetsUIResource[top=0,left=2,bottom=0,right=2],paintBorder=true,paintFocus=true,
pressedIcon=,rolloverEnabled=false,rolloverIcon=,rolloverSelectedIcon=,selectedIcon=,text=Click Me,
defaultCapable=true]
>>> frame.visible = True
>>> [greg:local]

Gradle

2010-11-10T23:07:00.000-08:00

Hibernate team has listed some compelling reasons to switch to Gradle.

Metrics

2010-11-09T17:29:00.000-08:00

The transformative power of identifying technical debt.

Gray Hat Python

2010-10-30T16:39:00.000-07:00

The book Gray Hat Python is as cool a book as I've ever read. Instead of showing how Windows works from the ground up, the author, Justin Seitz, shows how to investigate and manipulate programs and components. The book provides the details only when they are relevant to the problem at hand.

Here are the purposes of the X86 registers:
EAX - the Accumulator stores return values from function calls and is used for calculations
EDX - the Data register is used in conjunction with EAX
ECX - the Count register is used in looping operations
ESI - the Source Index register is used in data operations
EDI - the Destination Index is also used in data operations
EBP - the stack base pointer
ESP - the stack pointer
EBX - has no specific purpose
DR0 thru DR7 are the hardware debug registers

Hardware breakpoints use Interrupt 1 and software breakpoints use Interrupt 3. Stepping through instructions is accomplished with Interrupt 1.

The book provides knowledge of Windows security and how it is overcome and then goes on to provide the means to overcome malware with important tips like why it is important to use hardware breakpoints instead of soft breakpoints.

Here's a surprising example:

from ctypes import *
msvcrt = cdll.msvcrt
message = "1. Hello, World\n"
msvcrt.printf("Testing %s", message)

hello = c_char_p("2. Hello world")
print hello
print hello.value

c_char_p("2. Hello world")
2. Hello world
Testing 1. Hello, World

The book is a very interesting way to learn some Python, Windows OS and APIs and X86 Assembler and how these pieces fit together to provide or circumvent computer security. Nothing I've seen makes Windows come alive like this.

Open Source Integration

2010-09-27T16:31:00.000-07:00

Tutorial about Spring, Hibernate, Maven and Struts2 integration. And a pretty well named blog.

SQL Server XML Support

2010-09-24T15:07:00.000-07:00

I'm modifying an application that calls stored procedures which return XML. Naturally, more than just the Java has to be modified. I'm finding that I really enjoy working with SQL-Server, especially its more esoteric features. My first attempt FAILED! but, with the help of Microsoft forums, the second attempt WORKED!

I started with this:

SELECT 'Jon Stewart'       as "Employee/name",
       'home'              as "Employee/contact/phone/@type",
       '(555) 555-1212'    as "Employee/contact/phone",
       'cell'              as "Employee/contact/phone/@type",
       '(555) 555-1212'    as "Employee/contact/phone",
       '123 Main Street'   as "Employee/contact/street",
       null                as "Employee/contact/street2",
       'Dallas'            as "Employee/contact/city",
       'TX'                as "Employee/contact/state",
       '75025'             as "Employee/contact/zip"
FOR XML PATH('Employees'), ROOT('doc');

which I thought would give me:

<doc>
  <Employees>
    <Employee>
      <name>Jon Stewart</name>
      <contact>
        <phone type="home">(555) 555-1212</phone>
        <phone type="cell">(555) 555-1212</phone>
        <street>123 Main Street</street>
        <city>Dallas</city>
        <state>TX</state>
        <zip>75025</zip>
      </contact>
    </Employee>
  </Employees>
</doc>

but, the duplication of phone and phone/@type in the above SELECT statement resulted in an error and I had to use the following SELECT statement instead:

SELECT 
  (SELECT 'Jon Stewart' as "name",
    (SELECT 
      (SELECT 
        'home' as "phone/@type",
        '(555) 555-1212' as "phone"
      FOR XML PATH(''),TYPE),
      (SELECT 
        'cell' as "phone/@type",
        '(555) 555-1212' as "phone"
      FOR XML PATH(''),TYPE),
      '123 Main Street' as "street",
      null as "street2",
      'Dallas' as "city",
      'TX' as "state",
      '75025' as "zip"
    FOR XML PATH('contact'), TYPE)
  FOR XML PATH('Employee'),TYPE)
FOR XML PATH ('Employees'),ROOT('doc')

Monofesto

2010-09-22T16:01:00.000-07:00

I've played around with C# and F# on the Mac through the use of Mono (open-source .Net) and I saw that Mono could be used to run .Net on the iPhone but yet another surprise has been unveiled. A web framework, Manos de Mono has been announced in this Monofesto.

I believe a new Mac will be needed for this.

Best Job Ever

2010-09-20T16:58:00.000-07:00

I have the best job ever: home by 4:30, working with both Java and Microsoft technology, clean legacy code, consistent and sophisticated change management and deployment.

At my previous employer the code isn't as nice. They have a Java architect who wrote this code and had to have it explained twice what change was needed and why:

    try {
        resultset.close();
        statement.close();
        conn.close();
    } catch ...

OSGi for Low Coupling and High Cohesion

2010-09-07T08:26:00.000-07:00

Cohesion is an internal metric of a module’s focus. Coupling is an external metric of the degree to which each program module relies on other modules. The benefits of low coupling are (1.) little change is required to an application when a module is replaced with another and (2.) changes within a module do not effect other modules in the application.

Both Java and OSGi originally focused on small hardware devices. Java's attraction came from its promise "write once, run anywhere" which appealed to hardware vendors but, it was soon found that in Java applications dependencies were difficult to sort out, especially in regards to the classpath. Often it was found that different versions of the same jar were needed by different parts of the application. In short, jars are not a complete solution for providing modularity for Java applications.

OSGi is designed as a universal integration platform for the interoperability of applications and services. OSGi makes it possible for different components of an application to depend on different versions of a jar.

The use case of an application consuming services provided through OSGi requires both the consumer and the provider publish manifests. The manifest required is, in most ways, a standard jar manifest stored in the jar as META-INF/MANIFEST.MF. The jar which provides the service will export the package(s) in which the Java classes are found with a statement in the jar's manifest such as Export-Package: com.company.search. This statement only effects the Java components registered in the OSGi registry. It exposes all the public classes in the package.

The manifest in the jar file of the consumer will have an import like Import-Package: com.company.search. This statement imports all the public classes in the package.

Below I have created a MessagePrinter function that consumes messages produced by the HelloGoodbyeProducer. There are three modules, the activator, the producer and the consumer; each module is a separate project created in its own folder.

package com.activator;

import org.osgi.framework.BundleActivator;
import org.osgi.framework.BundleContext;
import org.osgi.framework.ServiceRegistration;

import com.producer.HelloGoodbyeProducer;
import com.producer.impl.HelloGoodbyeImpl;
import com.consumer.MessagePrinterService;
import com.consumer.impl.MessagePrinterServiceImpl;

public class HelloWorldActivator implements BundleActivator {

    public void start(BundleContext context) throws Exception {
        HelloGoodbyeProducer producer = getHelloGoodbyeProducer(context);
        MessagePrinterService printer = getMessagePrinter(context);
        printer.printMessage(producer.getHelloMessage());
    }

    public void stop(BundleContext context) throws Exception {
        HelloGoodbyeProducer producer = getHelloGoodbyeProducer(context);
        MessagePrinterService printer = getMessagePrinter(context); 
        printer.printMessage(producer.getGoodbyeMessage());
    }

    private HelloGoodbyeProducer getHelloGoodbyeProducer(BundleContext context) {
        ServiceRegistration reg = 
            context.registerService(HelloGoodbyeProducer.class.getName(), new HelloGoodbyeImpl(), null);
        HelloGoodbyeProducer producer = (HelloGoodbyeProducer) context.getService(reg.getReference());
        return producer;
    }

    private MessagePrinterService getMessagePrinter(BundleContext context) {
        ServiceRegistration reg = 
            context.registerService(MessagePrinterService.class.getName(), new MessagePrinterServiceImpl(), null);
        MessagePrinterService printer = (MessagePrinterService) context.getService(reg.getReference());
        return printer;
    }
}

src/META-INF/MANIFEST.MF

Manifest-Version: 1.0
Bundle-ManifestVersion: 2
Bundle-Name: HelloActivator
Bundle-SymbolicName: com.activator.HelloWorldActivator
Bundle-Version: 1.0.3
Bundle-Activator: com.activator.HelloWorldActivator
Import-Package: com.producer, com.producer.impl, com.consumer, com.consumer.impl, org.osgi.framework

ANT build.xml for the Activator

<project name="activator" default="jar" basedir=".">

    <property name="src.dir"           location="src"/> 
    <property name="build.dir"         location="bin"/>
    <property name="target.dir"        location="target"/>
    <property name="osgi.dir"          location="${user.home}/dev/bin/equinox-sdk-3"/>
    <property name="consumer.jar"      value="../consumer/target/consumer.jar"/>
    <property name="producer.jar"      value="../producer/target/producer.jar"/>
    <property name="manifest"          location="${build.dir}/META-INF/MANIFEST.MF"/>

    <path id="classpath">
        <pathelement location="${build.dir}"/>
        <pathelement location="${osgi.dir}/plugins/org.eclipse.osgi_3.5.2.R35x_v20100126.jar"/>
        <pathelement location="${consumer.jar}"/>
        <pathelement location="${producer.jar}"/>
    </path>

    <target name="clean">
        <delete dir="${build.dir}"/>
        <delete dir="${target.dir}"/>
    </target>

    <target name="init" depends="clean">
        <mkdir dir="${build.dir}"/>
        <mkdir dir="${target.dir}"/>
    </target>

    <target name="compile" depends="init">
        <javac srcdir="${src.dir}" 
            destdir="${build.dir}" 
            classpathref="classpath"/>
        <copy file="src/META-INF/MANIFEST.MF" todir="${build.dir}/META-INF"/>
    </target>

    <target name="jar" depends="compile">
       <jar jarfile="${target.dir}/${ant.project.name}.jar" 
            basedir="${build.dir}" manifest="${manifest}"/>
    </target>
</project>

Java Code for the Message Producer

package com.producer; 

public interface HelloGoodbyeProducer {
   String getHelloMessage();

   String getGoodbyeMessage();
}

package com.producer.impl; 
import com.producer.HelloGoodbyeProducer;

public class HelloGoodbyeImpl implements HelloGoodbyeProducer { 
    
    public String getHelloMessage() {
        return "Hello World!"; 
    }
    
    public String getGoodbyeMessage() { 
        return "Goodbye World!";
    }
}

src/META-INF/MANIFEST.MF

Manifest-Version: 1.0 
Bundle-ManifestVersion: 2 
Bundle-Name: HelloGoodbye
Bundle-SymbolicName: com.producer.HelloGoodbyeProducer
Bundle-Version: 1.0.3
Bundle-Activator: com.activator.HelloWorldActivator
Export-Package: com.producer, com.producer.impl

ANT build.xml for the Producer

<project name="producer" default="jar" basedir=".">

    <property name="src.dir"           location="src"/> 
    <property name="build.dir"         location="bin"/>
    <property name="target.dir"        location="target"/>
    <property name="manifest"          location="${build.dir}/META-INF/MANIFEST.MF"/>

    <path id="classpath">
        <pathelement location="${build.dir}"/>
    </path>

    <target name="clean">
        <delete dir="${build.dir}"/>
        <delete dir="${target.dir}"/>
    </target>

    <target name="init" depends="clean">
        <mkdir dir="${build.dir}"/>
        <mkdir dir="${target.dir}"/>
    </target>

    <target name="compile" depends="init">
        <javac srcdir="${src.dir}" 
            destdir="${build.dir}" 
            classpathref="classpath"/>
        <copy file="src/META-INF/MANIFEST.MF" todir="${build.dir}/META-INF"/>
    </target>

    <target name="jar" depends="compile">
       <jar jarfile="${target.dir}/${ant.project.name}.jar" 
            basedir="${build.dir}" manifest="${manifest}"/>
     </target>
</project>

Java Code for the Consumer

package com.consumer; 

public interface MessagePrinterService {
   public void printMessage(String message);
}

package com.consumer.impl; 
import com.consumer.MessagePrinterService;

public class MessagePrinterServiceImpl implements MessagePrinterService {
    public void printMessage(String message) {
        System.out.println(message);
    }
}

src/META-INF/MANIFEST.MF

Manifest-Version: 1.0 
Bundle-ManifestVersion: 2 
Bundle-Name: HelloGoodbye
Bundle-SymbolicName: com.producer.HelloGoodbyeProducer
Bundle-Version: 1.0.3
Bundle-Activator: com.activator.HelloWorldActivator
Export-Package: com.producer, com.producer.impl

build.xml for the Consumer

<project name="consumer" default="jar" basedir=".">
    
    <property name="src.dir"           location="src"/> 
    <property name="build.dir"         location="bin"/>
    <property name="target.dir"        location="target"/>
    <property name="manifest"          location="${build.dir}/META-INF/MANIFEST.MF"/>

    <path id="classpath">
        <pathelement location="${build.dir}"/>
    </path>

    <target name="clean">
        <delete dir="${build.dir}"/>
        <delete dir="${target.dir}"/>
    </target>

    <target name="init" depends="clean">
        <mkdir dir="${build.dir}"/>
        <mkdir dir="${target.dir}"/>
    </target>

    <target name="compile" depends="init">
        <javac srcdir="${src.dir}" 
            destdir="${build.dir}" 
            classpathref="classpath"/>
        <copy file="src/META-INF/MANIFEST.MF" todir="${build.dir}/META-INF"/>
    </target>

    <target name="jar" depends="compile">
       <jar jarfile="${target.dir}/${ant.project.name}.jar" 
            basedir="${build.dir}" manifest="${manifest}"/>
     </target>
</project>

It's Showtime!

[greg:equinox-SDK-3] java -jar plugins/org.eclipse.osgi_3.5.2.R35x_v20100126.jar -console

osgi> ss

Framework is launched.

id     State       Bundle
0      ACTIVE      org.eclipse.osgi_3.5.2.R35x_v20100126

osgi> install file:producer.jar
Bundle id is 4

osgi> install file:consumer.jar
Bundle id is 5

osgi> install file:activator.jar
Bundle id is 6

osgi> ss

Framework is launched.

id     State       Bundle
0      ACTIVE      org.eclipse.osgi_3.5.2.R35x_v20100126
4      RESOLVED    com.producer.HelloGoodbyeProducer_1.0.3
5      RESOLVED    com.consumer.MessagePrinterService_1.0.3
6      RESOLVED    com.activator.HelloWorldActivator_1.0.3

osgi> start 6
Hello World!

osgi> stop 6
Goodbye World!

osgi>

Charity

2010-09-02T14:42:00.000-07:00

Almost forty percent of U.S. households made donations for Haiti this year.

Getting to Know Threads

2010-08-31T08:13:00.000-07:00

Threads have six possible states:
new, runnable, blocked, waiting, timed waiting, terminated

A thread terminates when its run() method returns.

interrupt() can interrupt a thread (or, it may cause a SecurityException to be thrown). If the thread is in a non-blocked status, it can call Thread.getCurrentThread().isInterrupted() to check if interrupt has been called. If the thread is in a blocked status such as sleep, another thread's call to interrupt() will cause an InterruptedException which will cause the thread to exit sleep or wait.

The functionality of the synchronized keyword has been extended with java.util.concurrent.locks.Lock.

Below is code which shows two means of creating threads. The code performs the simplest use case for threads, no shared state.

public class Main extends Thread {
    
    public Main(String name) {
        super(name);
    }
    
    public static void main(String[] args) throws Exception {
        Main m = new Main("1st");
        m.start(); 
        
        new Thread(new Runnable() {
            @Override
            public void run() {
                for (int x = 0; x < 5; x++) { 
                    System.out.println("Runnable:  name=" + Thread.currentThread().getName() + ": x=" + x);
                    try { 
                        sleep(10);
                    } catch(InterruptedException e) {
                        System.out.println("Runnable interrupted");
                    }
                }
            }
        }, "2nd").start();
    }
    
    @Override
    public void run() {
        for (int x = 0; x < 5; x++) { 
            System.out.println("Thread:    name=" + Thread.currentThread().getName() + ": x=" + x);
            try { 
                sleep(10);
            } catch(InterruptedException e) {
                System.out.println("Thread interrupted");
            }
        }
    } 
}

<project name="java_concurrency" default="run" basedir=".">
    <property name="src.dir"           location="src/main/java"/> 
    <property name="test.src.dir"      location="src/test/java"/>
    <property name="build.dir"         location="build"/>
    <property name="classes.dir"       location="build/classes"/>
    <property name="tests.dir"         location="build/tests"/>
    <property name="junit.jar"         location="lib/junit/junit-4.8.2.jar"/>
    <path id="compile.classpath">
        <pathelement location="${classes.dir}"/>
    </path>

    <path id="test.classpath">
        <pathelement location="${classes.dir}"/>
        <pathelement location="${junit.jar}"/>
        <pathelement location="${tests.dir}"/>
    </path>
    
    <path id="run.classpath">
        <pathelement location="${classes.dir}"/>
    </path>

    <target name="clean">
        <delete dir="${build.dir}"/>
    </target>

    <target name="init" depends="clean">
        <mkdir dir="${classes.dir}"/>
        <mkdir dir="${tests.dir}"/>
    </target>

    <target name="compile" depends="init">
        <javac srcdir="${src.dir}" 
            destdir="${classes.dir}" 
            classpathref="compile.classpath"/>
        <javac srcdir="${test.src.dir}" 
            destdir="${tests.dir}" 
            classpathref="test.classpath"/>
    </target>
  
    <target name="test" depends="compile">
        <junit fork="yes" printsummary="yes">
            <classpath refid="test.classpath"/>
            <formatter type="plain" usefile="false"/>
            <test name="MainTest"/>
        </junit>
    </target>
    
    <target name="run" depends="compile">
        <java fork="true" dir="${classes.dir}" classname="Main" classpathref="run.classpath"/>
    </target> 
</project>

[greg:java_concurrency] ant
. . . 
run:
     [java] Runnable:  name=2nd: x=0
     [java] Thread:    name=1st: x=0
     [java] Runnable:  name=2nd: x=1
     [java] Thread:    name=1st: x=1
     [java] Runnable:  name=2nd: x=2
     [java] Thread:    name=1st: x=2
     [java] Runnable:  name=2nd: x=3
     [java] Thread:    name=1st: x=3
     [java] Runnable:  name=2nd: x=4
     [java] Thread:    name=1st: x=4
[greg:java_concurrency]

Magic for Rails

2010-08-30T06:37:00.000-07:00

No, this magic is not a new gem, just a solution for updating Rails 3.

My Rubygems failed when I tried to update Rails to Rails 3 this morning. I found that running sudo gem cleanup did all that was necessary for the Rails 3 update to run successfully.

See the Ruby on Rails 3 Tutorial for information on the new version of the framework.

JUnit, DateFormat, Calendar and ANT

2010-08-28T13:49:00.000-07:00

It is not necessary to test Java's DateFormat class but, as a means of verifying our knowledge, this code does just that.

DateAndTimeFormattingTest.java

import java.text.DateFormat;
import java.util.Calendar;
import java.util.GregorianCalendar;
import java.util.Date;
import org.junit.*;
import static org.junit.Assert.*;

public class DateAndTimeFormattingTest {
    DateFormat dateOnly = DateFormat.getDateInstance(DateFormat.MEDIUM);
    DateFormat dateAndTime = DateFormat.getDateTimeInstance(DateFormat.MEDIUM, DateFormat.MEDIUM);
 
    @Test 
    public void testDateOnly() {
        Calendar cal = new GregorianCalendar(2010, 11, 31);
        Date date = cal.getTime();
        assertEquals("Dec 31, 2010", dateOnly.format(date));
    }
 
    @Test 
    public void testDateAndTime() {
        Calendar cal = new GregorianCalendar(2010, 11, 31);
        Date date = cal.getTime();
        assertEquals("Dec 31, 2010 12:00:00 AM", dateAndTime.format(date));
    }
}

build.xml

<project name="calendar_test" default="test" basedir=".">
    <property name="src.dir"       location="src/main/java"/> 
    <property name="test.src.dir"  location="src/test/java"/>
    <property name="build.dir"     location="build"/>
    <property name="classes.dir"   location="build/classes"/>
    <property name="tests.dir"     location="build/tests"/>
    <property name="reports.dir"   location="build/reports"/>
    <property name="junit.lib"     location="lib/junit/junit-4.8.2.jar"/>
    <path id="classpath">
        <pathelement location="${classes.dir}"/>
    </path>

    <path id="test.classpath">
        <pathelement path="${classpath}"/>
        <pathelement location="${junit.lib}"/>
        <pathelement location="${tests.dir}"/>
    </path>

    <target name="clean">
        <delete dir="${build.dir}"/>
    </target>

    <target name="init" depends="clean">
        <mkdir dir="${classes.dir}"/>
        <mkdir dir="${tests.dir}"/>
        <mkdir dir="${reports.dir}"/>
    </target>

    <target name="compile" depends="init">
        <javac srcdir="${src.dir}" 
             destdir="${classes.dir}" 
             classpathref="classpath"/>
        <javac srcdir="${test.src.dir}" 
             destdir="${tests.dir}" 
             classpathref="test.classpath"/>
    </target>
  
    <target name="test" depends="compile">
        <junit fork="yes" printsummary="yes">
            <classpath refid="test.classpath"/>
            <formatter type="plain" usefile="false"/>
            <test name="DateAndTimeFormattingTest"/>
        </junit>
    </target>

</project>

Running ANT

[greg:DateAndTimeFormattingTest] ant
Buildfile: build.xml

clean:
   [delete] Deleting directory /Users/greghelton/dev/src/java/DateAndTimeFormattingTest/build

init:
    [mkdir] Created dir: /Users/greghelton/dev/src/java/DateAndTimeFormattingTest/build/classes
    [mkdir] Created dir: /Users/greghelton/dev/src/java/DateAndTimeFormattingTest/build/tests
    [mkdir] Created dir: /Users/greghelton/dev/src/java/DateAndTimeFormattingTest/build/reports

compile:
    [javac] Compiling 1 source file to /Users/greghelton/dev/src/java/DateAndTimeFormattingTest/build/tests

test:
    [junit] Running DateAndTimeFormattingTest
    [junit] Testsuite: DateAndTimeFormattingTest
    [junit] Tests run: 2, Failures: 0, Errors: 0, Time elapsed: 0.023 sec
    [junit] Tests run: 2, Failures: 0, Errors: 0, Time elapsed: 0.023 sec
    [junit] 
    [junit] Testcase: testDateOnly took 0.009 sec
    [junit] Testcase: testDateAndTime took 0 sec

BUILD SUCCESSFUL
Total time: 1 second
[greg:DateAndTimeFormattingTest]

Erlang, RabbitMQ and Spring

2010-08-17T11:58:00.000-07:00

Erlang was selected for use as the development language for RabbitMQ because of its excellent threading and multicore capabilities. SpringSource acquired RabbitMQ in April 2010 for incorporation into Spring Integration.

After installing Erlang, save the following code in a file named 'math1.erl':

-module(math1).
-export([factorial/1]).

factorial(0) -> 1;
factorial(N) -> N * factorial(N-1).

Start the Erlang console, compile the module and run the function:

[greg:erlang] erl
1> c(math1.erl).                  
{ok,math1}
2> math1:factorial(25).
15511210043330985984000000
3>

Setup RabbitMQ

Once Erlang works, you can run RabbitMQ. After downloading and extracting the archive, I created 'log', 'mnesia' and 'config' folders in my rabbitmq_server folder and then set these environment variables.

export RABBIT=/bin/rabbitmq_server-1.8.1
export RABBITMQ_MNESIA_BASE=$RABBIT/mnesia
export RABBITMQ_LOG_BASE=$RABBIT/log
export RABBITMQ_NODENAME=gregs
export RABBITMQ_NODE_IP_ADDRESS=0.0.0.0
export RABBITMQ_NODE_PORT=5672
export RABBITMQ_CLUSTER_CONFIG_FILE=$RABBIT/config/rabbitmq_cluster.config
export RABBITMQ_CONFIG_FILE=$RABBIT/config/rabbitmq

Run RabbitMQ

[greg:rabbitmq_server-1.8.1] ./sbin/rabbitmq-server

Client Code

Examples of Groovy clients using the RabbitMQ server are shown here.

Java client code is explained here.

Running the Included LoanBroker Example

[greg:~] cd spring-integration-2.0.0.M6/samples/loanbroker 
[greg:loan-broker] mvn compile
[greg:loan-broker] mvn test
. . . 
INFO : org.springframework.integration.samples.loanbroker.demo.LoanBrokerSharkDetectorDemo - 
********* Best Quote: 
====== Loan Quote =====
Lender: StubBank-13
Loan amount: $253,664
Quote Date: Wed Aug 18 08:44:37 CDT 2010
Expiration Date: Sat Sep 11 08:44:37 CDT 2010
Term: 19 years
Rate: 5.130192%
=======================

INFO : org.springframework.integration.samples.loanbroker.stubs.CreditBureauStub - Credit Score: 797
INFO : org.springframework.integration.samples.loanbroker.demo.LoanBrokerSharkDetectorDemo - 
********* All Quotes: 
INFO : org.springframework.integration.samples.loanbroker.demo.LoanBrokerSharkDetectorDemo - 
====== Loan Quote =====
Lender: StubBank-0
Loan amount: $272,807
Quote Date: Wed Aug 18 08:44:37 CDT 2010
Expiration Date: Mon Aug 23 08:44:37 CDT 2010
Term: 19 years
Rate: 5.1708126%
=======================
. . .

GRASP Patterns

2010-08-15T20:15:00.000-07:00

GRASP Patterns

I originally thought it was a shame that the principles of high cohesion and low coupling had to be explicitly listed as design patterns. I suppose that at some point Mr. Larman had to direct a student to apply what he had learned to the benefit of his code.

7 Wastes of Software Development

Mary and Tom Poppendieck identified these seven wastes:

Does it all boil down to "Think Globally, Act Locally"?

Spring Framework API JavaDoc

2010-08-13T06:30:00.001-07:00

Spring Framework API JavaDoc

So Long IronRuby

2010-08-06T16:46:00.000-07:00

Microsoft has done a good job with languages but that seems to be changing. A former Microsoft employee talks about the evolution of Ruby on .Net, "Overall, I see a serious lack of commitment to IronRuby, and dynamic language on .NET in general. IronRuby’s IDE support in Visual Studio hasn’t been released yet."

I wonder what this means for F#?

Refactoring

2010-08-06T12:45:00.000-07:00

A poorly designed system is hard to change. Hard because it is hard to figure out where the changes are needed.
Refactoring by Martin Fowler

Jetty and ANT

2010-08-05T16:31:00.000-07:00

<project name="beers" default="war" basedir=".">
 <property name="src"       location="src/main/java"/> 
 <property name="test.src"  location="src/test/java"/>
 <property name="classes"   location="build/classes"/>
 <property name="tests"     location="build/tests"/>
 <property name="jetty"     location="../jetty-6.1.25/lib"/>
 <property name="warfile"   value="beers.war"/>
 <property name="server.webapps.dir" location="..\jetty-6.1.25\webapps"/>
 
  <path id="classpath">
      <pathelement location="${classes}"/>
      <fileset dir="${jetty}" includes="**/*.jar"/>
  </path>

  <path id="test.classpath">
      <pathelement path="${classpath}"/>
      <pathelement location="lib/junit/junit-4.8.2.jar"/>
      <pathelement path="${tests}"/>
  </path>

  <target name="clean">
      <delete dir="build"/>
  </target>
 
  <target name="init" depends="clean">
      <mkdir dir="${classes}"/>
      <mkdir dir="${tests}"/>
  </target>

  <target name="compile" depends="init">
      <javac srcdir="${src}" 
        destdir="${classes}" classpathref="classpath"/>
      <javac srcdir="${test.src}" 
        destdir="${tests}" classpathref="test.classpath"/>
  </target>
  
  <target name="war" depends="compile">
      <war destfile="${warfile}" webxml="src/metadata/web.xml">
          <fileset dir="src/jsp"/>
          <lib dir="lib"/>
          <classes dir="build/classes"/>
      </war>
      <copy file="${warfile}" todir="${server.webapps.dir}"/>
  </target>

</project>

Jetty is started by the command:

C:\path-to-jetty\jetty-6.1.25>java -jar start.jar

JRuby

2010-08-05T13:18:00.000-07:00

Reading the Pragmatic Programmers' RSpec and JRuby books simultaneously.

JRuby Complete looks like a winner.

As does this free, online book about Ruby 1.9.

Lax Website Security

2010-08-04T14:03:00.000-07:00

A large sampling of websites' authentication and password security implemented with cryptographic hashes, salting and TLS (Transport Layer Security) is the subject of this blog post.

Call Me Proficient

2010-08-03T17:14:00.000-07:00

GRAPE

2010-08-01T14:34:00.000-07:00

GRAPE, the 'Groovy Adaptable Packaging Engine' allows an application's dependencies to be specified in the code or as arguments on the command line and, at runtime, the dependencies will be downloaded and added to the application's classloader.

An example of Groovy, Hibernate (not GORM), HSQL and SLF4J.

The following example is from the GRAPE homepage.

import org.mortbay.jetty.Server
import org.mortbay.jetty.servlet.*
import groovy.servlet.*

@Grab(group = 'org.mortbay.jetty', module = 'jetty-embedded', version = '6.1.0')
def runServer(duration) {
    def server = new Server(8080)
    def context = new Context(server, "/", Context.SESSIONS);
    context.resourceBase = "."
    context.addServlet(TemplateServlet, "*.gsp")
    server.start()
    sleep duration
    server.stop()
}

runServer(10000)

Online Programming Books

2010-07-28T06:10:00.000-07:00

Online Programming Books

CSS Zen Garden

2010-07-22T18:03:00.000-07:00

1996 Geocities. What a hoot.

Dependency Inversion Principle

2010-07-13T09:31:00.000-07:00

"traditional software development methods, such as Structured Analysis and Design, tend to create software structures in which high level modules depend upon low level modules, and in which abstractions depend upon details." Robert C Martin, 'The Dependency Inversion Principle', C++ Report, 1996

Top-Down design causes developers to create code in which high level business rules depend on low level functions like IO. This means the business functionality is not reusable because it is coupled to the IO functionality.

Adding conditional statements so that the business function can use one set of IO routines in one case and another set in a second case soon this becomes difficult to manage. This strategy of modifying code to make it dependent on even more low level routines violates another principle, the Open Closed Principle which Mr. Martin also wrote about.

Of course, any number of people will say that one design is as good as another, that it is okay to duplicate the business logic and couple the new copy to a different set of low level components. Unfortunately, it is rare that one person can change the mind of another as evidenced by today's news: Researchers at the University of Michigan found that when misinformed people were exposed to facts, they rarely changed their minds and they often became even more strongly set in their beliefs.

This phenomenon was commented on by Darwin in 1871:
Ignorance more frequently begets confidence than does knowledge

Loading a Clojure Script

2010-07-09T14:00:00.000-07:00

Create hello.clj

(defn hello 
   "Writes hello message to *out*. Calls you by username" 
   [username] 
   (println (str "Hello, " username)))

Run the Clojure script from within the Clojure REPL by executing the following:

java -cp .:clojure.jar:clojure-contrib.jar:jline-0.9.94.jar jline.ConsoleRunner clojure.main
Clojure 1.2.0-master-SNAPSHOT
user=> (load-file "hello.clj")
#'user/hello
user=> (hello 'Greg)
Hello, Greg
nil
user=>

A similar but different alternative.

(defn hello 
 "Displays hello message as function result" 
 [username] 
 (str "Hello, " username " and goodbye ")
)

user=> (load-file "hello.clj")
#'user/hello
user=> (hello "Greg")         
"Hello, Greg and goodbye "
user=>

Cheat Sheet Roundup

2010-07-06T19:51:00.000-07:00

from Smashing Magazine

Yellowstone

2010-07-02T07:54:00.000-07:00

Yellowstone Trip photos

Wiring Spring Beans

2010-05-29T17:18:00.000-07:00

Spring in Action (3rd edition) by Craig Walls is superb. (Spring's documentation is also eminently practical.) In this article, I take Craig's example of a knight, a minstrel and a quest for the holy grail and extend it in order to get a little practice wiring beans together.

I took the example from the first chapter of Spring in Action and added the class QuestExpedition to separate the behavior of how the quest is achieved from the quest as an objective or goal. One design being better than the other would depend on the ubiquitous language of the domain driven design. As I envision it, the personnel participating in the quest and the itinerary belong to a separate concern. I created QuestExpedition to encapsulate such concerns.

In Craig's code, the knight knows upon which quest he is embarked. In real life a knight would know the details of a quest on which he might embark but, in software, we only model the required behavior of the application, not real life. I removed the Knight.embarkOnQuest() method because it only calls Quest.embark(). In my application, I have the QuestExpedition embark rather than have the Knight embark.

QuestApp.java

import org.springframework.context.ApplicationContext; 
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class QuestApp { 
  public static void main(String[] args) {
    ApplicationContext ctx = new ClassPathXmlApplicationContext("beans.xml");
    QuestExpedition expedition = (QuestExpedition)ctx.getBean("expedition");
    expedition.embark();
    expedition.reportStatus();
  }
}

QuestExpedition.java

import java.util.*; 

public class QuestExpedition {
  Quest quest;
  List knights;
  List minstrels;
  List destinations;
 
  public void embark() {
    System.out.println(toString());
  }
 
  public void setQuest(Quest quest) {this.quest = quest;}
  public void setKnights(List knights) {this.knights = knights;}
  public void setMinstrels(List minstrels) {this.minstrels = minstrels;}
  public void setDestinations(List destinations) {this.destinations = destinations;}
 
  public void reportStatus() {
    for (Minstrel m : minstrels) 
      for (Knight k : knights) 
        m.praiseKnight(k, quest); 
  }
 
  @Override
  public String toString() { 
    String comma = "";
    StringBuilder sb = new StringBuilder(); 
    sb.append("Embarking on quest to " + quest.toString());
    sb.append("\n with Knights: ");
    for (Knight k : knights) {  
      sb.append(comma + k.toString());
      comma = ", ";
    }
    sb.append("\n and with Minstrels: ");
    comma = "";
    for (Minstrel m : minstrels) {  
      sb.append(comma + m.toString());
      comma = ", ";
    }
    sb.append("\n Itinerary: ");
    comma = "";
    for (String dest : destinations) {
      sb.append(comma + dest);
      comma = ", ";
    }
    return sb.toString();
  }
}

beans.xml

<?xml version="1.0" encoding="UTF-8"?> 

<beans xmlns="http://www.springframework.org/schema/beans"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
  xsi:schemaLocation="http://www.springframework.org/schema/beans
    http://www.springframework.org/schema/beans/spring-beans.xsd"> 

  <bean id="expedition" class="QuestExpedition">
   <property name="quest" ref="quest"/>
   <property name="knights">
    <list>
     <ref bean="count"/>
     <ref bean="duke"/>
     <ref bean="earl"/>
    </list>
   </property>
   <property name="minstrels">
    <list>
     <ref bean="troubadour"/>
    </list>
   </property>
   <property name="destinations">
    <list>
     <value>Rome</value>
     <value>Crete</value>
     <value>Malta</value>
    </list>
   </property>
  </bean>
  
  <bean id="quest" class="SlayDragonQuest">
   <constructor-arg value="Puff" />
  </bean>
  <bean id="count" class="Knight">
   <constructor-arg value="Count" />
   <constructor-arg value="Chuck" />
  </bean>
  <bean id="duke" class="Knight">
   <constructor-arg value="Duke" />
   <constructor-arg value="Danny" />
  </bean>
  <bean id="earl" class="Knight">
   <constructor-arg value="Earl" />
   <constructor-arg value="Earle" />
  </bean>
  <bean id="troubadour" class="Minstrel">
   <constructor-arg value="Troubadour" />
   <constructor-arg value="Steve" />
  </bean>
</beans>

Quest.java

public abstract class Quest {
  String name;
  String description;
  @Override
  public String toString() {
    return description + " " + name;
  }
}

HolyGrailQuest.java

public class HolyGrailQuest extends Quest {
  HolyGrailQuest(String name) {
    this.name = name;
    this.description = "find and acquire the grail"; 
  }
}

RescueDamselQuest.java

public class RescueDamselQuest extends Quest {
  RescueDamselQuest(String name) {
    this.name = name;
    this.description = "rescue the damsel";
  }
}

SlayDragonQuest.java

public class SlayDragonQuest extends Quest {
  SlayDragonQuest(String name) {
    this.name = name;
    this.description = "slay the dragon";
  }
}

Person.java

public class Person {
  final private String name;
  final private String honorific;
  Person(String honorific, String name) {
    this.name = name;
    this.honorific = honorific;
  }
  @Override
  public String toString() {
    return honorific + " " + name;
  }
}

Minstrel.java

public class Minstrel extends Person {
  Minstrel(String honorific, String name) {
    super(honorific, name); 
  }
  public void praiseKnight(Knight knight, Quest quest) {
    System.out.println("Bold " + knight.toString() + " pledged himself to " + quest.toString());
  }
}

Knight.java

public class Knight extends Person { 
  Knight(String honorific, String name) {
    super(honorific, name);
  }
}

ANT build.xml

<project name="GrailsQuest" default="run" basedir=".">
 <property name="src"       location="src/main/java"/> 
 <property name="test.src"  location="src/test/java"/>
 <property name="build"     location="build/classes"/>
 <property name="tests"     location="build/tests"/>
 <property name="spring"    location="${user.home}/dev/lib/spring-framework-3"/>
 
  <path id="classpath">
    <pathelement location="${build}"/>
    <fileset dir="${spring}" includes="**/*.jar"/>
  </path>

  <path id="test.classpath">
    <pathelement path="${classpath}"/>
    <pathelement location="${user.home}/dev/lib/junit/junit-4.6.jar"/>
    <pathelement path="${build}"/>
    <pathelement path="${tests}"/>
  </path>

  <target name="clean">
    <delete dir="${build}"/>
  </target>
 
  <target name="init" depends="clean">
    <mkdir dir="${build}"/>
    <mkdir dir="${tests}"/>
  </target>

  <target name="compile" depends="init">
      <javac srcdir="${src}" 
             destdir="${build}" classpathref="classpath"/>
    <javac srcdir="${test.src}" 
            destdir="${tests}" classpathref="test.classpath"/>
  </target>

  <target name="run" depends="compile">
    <java classname="QuestApp">
      <classpath><path refid="classpath"/></classpath>
    </java>
  </target>
</project>

Running the ANT Command for the Project

[greg:Quest] ant
. . .
     [java] Embarking on quest to slay the dragon Puff
     [java]   with Knights: Count Chuck, Duke Danny, Earl Earle
     [java]   and with Minstrels: Troubadour Steve
     [java]   Itinerary: Rome, Crete, Malta
     [java] Bold Count Chuck pledged himself to slay the dragon Puff
     [java] Bold Duke Danny pledged himself to slay the dragon Puff
     [java] Bold Earl Earle pledged himself to slay the dragon Puff

BUILD SUCCESSFUL
Total time: 5 seconds

ADHD

2010-05-22T15:50:00.000-07:00

Scientists at the University of Montreal and Harvard University have found a connection between exposure to organophosphate pesticides, at levels common among US children, and increased risk of Attention-Deficit Hyperactivity Disorder.

Prevalence of ADHD varies among states, with Colorado having the lowest rate at 5% and Alabama having the highest rate of 11.1%.

Hudson Continuous Integration

2010-05-18T17:54:00.000-07:00

Start with Subversion

Create a temporary project structure:

[greg:~] mkdir /tmp/taxi /tmp/taxi/trunk /tmp/taxi/branches /tmp/taxi/tags

Import the temporary project structure then delete it and switch to the source folder:

[greg:~] svnadmin create /Library/Subversion/Repository/taxi 
[greg:~] svn import /tmp/taxi file:///Library/Subversion/Repository/taxi -m 'initial import'
Adding         /tmp/taxi/trunk
Adding         /tmp/taxi/branches
Adding         /tmp/taxi/tags

Committed revision 1.
[greg:~] rm -rf /tmp/taxi
[greg:~] cd dev/src/java/taxi
[greg:taxi] cd ..

Checkout the empty project:

[greg:java] svn co file:////Library/Subversion/Repository/taxi 
A    taxi/trunk
A    taxi/branches
A    taxi/tags
Checked out revision 1.

Finally, start the server and list the projects:

[greg:java] svnserve -d -r /Library/Subversion/Repository
[greg:java] svn list svn://localhost/taxi
branches/
tags/
trunk/
[greg:java] cd taxi

Create the source and commit it:

[greg:taxi] svn add trunk/src
A         trunk/src
A         trunk/src/main
A         trunk/src/main/java
A         trunk/src/main/java/Taxi.java
[greg:taxi] svn commit -m 'added swing program'
Adding         trunk/src
Adding         trunk/src/main
Adding         trunk/src/main/java
Adding         trunk/src/main/java/Taxi.java
Transmitting file data .
Committed revision 2.
[greg:taxi] 
[greg:taxi] svn add trunk/taxi.png
A  (bin)  trunk/taxi.png
[greg:taxi] svn commit -m 'added taxi icon'
Adding  (bin)  trunk/taxi.png
Transmitting file data .
Committed revision 3.
[greg:taxi]

Start Hudson by using the Java Web Start instance found at http://www.continuous-integration-with-hudson.org or by running the jar as follows:

[greg:hudson] java -jar hudson.war --httpPort=8282

And now, open your browser to http://localhost:8282 and click on the "Manage Hudson" link and then the "Configure System" link. Here. I simply unselected the checkbox for "Install Automatically" and entered the values for Maven home and Java home. Save your changes.

Now, click on the "New Job" link. All that is required here is to enter a project name and, under 'Source Code Management', select Subversion and enter the value for the project's repository URL. I entered the value I used above:
file:////Library/Subversion/Repository/taxi

I saved my changes and ran a manual build which ran satisfactorily. Then, I clicked on the 'Configure Job' link and selected a build trigger of 'Poll SCM' which caused the display of the 'Schedule' prompt. Clicking on the question mark brought up helpful hints and examples. I selected the choice for 'every minute' and pasted it in the Schedule input field. Click 'Save'.

Now, simply commit a source file and, in less than one minute, Hudson shows a new build has been completed.

First github repo

2010-05-15T08:53:00.000-07:00

Generate a ssh key per these instructions. Then run the following two commands to cache the credentials for the session.

[greg:taxi] eval 'ssh-agent'
. . .
echo Agent pid 18284;
[greg:taxi] ssh-add
Enter passphrase for /Users/greghelton/.ssh/id_rsa: 
Identity added: /Users/greghelton/.ssh/id_rsa (/Users/greghelton/.ssh/id_rsa)

Then, add the project to the github repo:

[greg:taxi] mkdir ../taxi_bkup
[greg:taxi] cp -R *  ../taxi_bkup
[greg:taxi] git init
Initialized empty Git repository in /Users/greghelton/dev/src/java/taxi/.git/
[greg:taxi] git add .
[greg:taxi] git commit -m 'first commit'
[master (root-commit) 3563bb5] first commit
 2 files changed, 128 insertions(+), 0 deletions(-)
 create mode 100644 src/main/java/Taxi.java
 create mode 100644 taxi.png
[greg:taxi] git remote add origin git@github.com:greghelton/taxi.git
[greg:taxi] git push origin master
Counting objects: 8, done.
Delta compression using up to 2 threads.
Compressing objects: 100% (5/5), done.
Writing objects: 100% (8/8), 4.00 KiB, done.
Total 8 (delta 0), reused 0 (delta 0)
To git@github.com:greghelton/taxi.git
 * [new branch]      master -> master
[greg:taxi]

Obtaining a Secure Socket

2010-05-12T15:19:00.000-07:00

First, initialize a keystore.

[greg:secure] keytool -genkey -alias servercert -keyalg RSA -keysize 1024 
 -dname "CN=FederalReserveBank,OU=DRE,O=BEA,L=Dallas,S=TX,C=US" -keypass password 
 -keystore keystore.jks -storepass password
[greg:secure] keytool -list -v -keystore keystore.jks
Enter keystore password: password 
Keystore type: JKS
Keystore provider: SUN

Your keystore contains 1 entry

Alias name: servercert
Creation date: May 12, 2010
Entry type: PrivateKeyEntry
Certificate chain length: 1
Certificate[1]:
Owner: CN=FederalReserveBank, OU=DRE, O=BEA, L=Dallas, ST=TX, C=US
Issuer: CN=FederalReserveBank, OU=DRE, O=BEA, L=Dallas, ST=TX, C=US
Serial number: 4beb2922
Valid from: Wed May 12 17:18:10 CDT 2010 until: Tue Aug 10 17:18:10 CDT 2010
Certificate fingerprints:
  MD5:  98:A4:50:E3:27:7A:F3:AC:55:4B:B4:C1:C6:A4:B3:04
  SHA1: 37:72:D3:1B:01:70:30:10:24:D0:EF:27:BE:65:1C:B5:FA:F6:77:1B
  Signature algorithm name: SHA1withRSA
  Version: 3


*******************************************
*******************************************


[greg:secure]

Assigning Hudson A Port

2010-05-05T20:27:00.000-07:00

[greg:hudson] java -jar hudson.war --httpPort=8282

Assigning Jetty A Port

2010-05-05T20:08:00.000-07:00

[greg:jetty-6.1.21] java -jar -Djetty.port=8181 start.jar

Clojure 1.2 Protocols

2010-04-26T19:39:00.000-07:00

Stuart Halloway's video on Clojure 1.2 Protocols.

java.sql And Clojure

2010-04-20T11:18:00.000-07:00

Clojure has a SQL package that wraps the native Java classes with LISP-like syntax. I however want to learn Clojure-Java interop so, this example makes direct calls to the Java API from Clojure. I'll use HSQL and create and populate a table then, with Clojure, attempt to read from the table.

Start HSQL

[greg:hsqldb] java -cp lib/hsqldb.jar org.hsqldb.server.Server --database.0 file:myclojuredb --dbname.0 clojuredb

Start the SqlTool Commandline Client

[greg:hsqldb] java -jar lib/hsqldb.jar --inlineRc URL=jdbc:hsqldb:hsql://localhost,USER=sa

Or, Start the Swing HSQL client

[greg:hsqldb] java -cp lib/hsqldb.jar org.hsqldb.util.DatabaseManagerSwing

In the Swing HSQL client, I connect to the myclojuredb and run these statements:

create table Authors (id INT GENERATED BY DEFAULT AS IDENTITY PRIMARY KEY, firstName VARCHAR(50), lastName VARCHAR(50));
insert into Authors VALUES(NULL, 'Kurt', 'Vonnegut');
insert into Authors VALUES(NULL, 'John', 'Steinbeck');
select * from Authors;

Start the Clojure REPL

[greg:clojure-1.1.0] java -cp .:clojure.jar:jline-0.9.94.jar:../hsqldb/lib/hsqldb.jar jline.ConsoleRunner clojure.main

Run the Clojure - Java Interop to Execute the JDBC

user=> (import '(java.sql Connection DriverManager Statement ResultSet))
java.sql.ResultSetMetaData
user=> (Class/forName "org.hsqldb.jdbc.JDBCDriver")                                                    
org.hsqldb.jdbc.JDBCDriver
user=> (def conn (DriverManager/getConnection "jdbc:hsqldb:hsql://localhost/clojuredb", "SA", ""))     
#'user/conn
user=> (def stmt (.createStatement conn))                                                              
#'user/stmt
user=> (def rs (.executeQuery stmt "SELECT * FROM Authors"))                                           
#'user/rs
user=> (.next rs)
true
user=> (.getInt rs 1)
0
user=> (.getString rs 2)
"Kurt"
user=> (.getString rs 3)
"Vonnegut"
user=>

JRuby Steps 4 and 5

2010-04-16T06:35:00.000-07:00

The JRuby 'Getting Started' page lists three steps:

1. Download JRuby: Visit the download page and grab the binaries for the latest JRuby release.
2. Unpack JRuby: Unpack the file you downloaded. You’ll then have a "jruby-" directory.
3. Run JRuby: The JRuby startup script lives in the "bin" directory. Run "bin/jruby -v" to confirm it.

I found that the following steps are also required:

[greg:jruby-1.5.0.RC1] export JRUBY_HOME=/Users/greghelton/dev/bin/jruby-1.5.0.RC1
[greg:jruby-1.5.0.RC1] export PATH=$PATH:$JRUBY_HOME/bin

Then, to run jirb:

[greg:jruby-1.5.0.RC1] bin/jirb

Or, to run sinatra, first edit hi.rb

require 'rubygems'
require 'sinatra'
get '/hi' do
  "Hello World!"
end

and run the class

[greg:project1] sudo jgem install sinatra
[greg:project1] jruby ./hi.rb
== Sinatra/0.9.4 has taken the stage on 4567 for development with backup from WEBrick
[2010-04-16 18:09:50] INFO  WEBrick 1.3.1
[2010-04-16 18:09:50] INFO  ruby 1.8.7 (2010-04-14) [java]
[2010-04-16 18:09:50] INFO  WEBrick::HTTPServer#start: pid=4475 port=4567

then open your browser to ...

http://localhost:4567/hi

Installing activerecord for JRuby

This site is a big help but I had to do things a little differently. The command 'rake jgem' didn't work but 'rake gem' did then, strangely, 'jgem install ...' worked as the next step.

[greg:ruby] export JRUBY_HOME=/Users/greghelton/dev/bin/jruby-1.5.0.RC1
[greg:ruby] export PATH=$PATH:$JRUBY_HOME/bin
[greg:ruby] mkdir active
[greg:ruby] cd active
[greg:active] git clone git://github.com/rails/rails.git
Initialized empty Git repository in /Users/greghelton/dev/src/ruby/active/rails/.git/
remote: Counting objects: 163266, done.
remote: Compressing objects: 100% (36468/36468), done.
remote: Total 163266 (delta 125957), reused 162169 (delta 125035)
Receiving objects: 100% (163266/163266), 28.37 MiB | 326 KiB/s, done.
Resolving deltas: 100% (125957/125957), done.
[greg:active] cd rails
[greg:rails] rake gem
             ... many lines reported by the build ...
[greg:rails] ls -al activesupport/pkg
total 584
drwxr-xr-x   3 greghelton  staff     102 Apr 22 01:19 .
drwxr-xr-x  12 greghelton  staff     408 Apr 22 01:19 ..
-rw-r--r--   1 greghelton  staff  295424 Apr 22 01:19 activesupport-3.0.0.beta3.gem
[greg:rails] sudo jgem install ./activesupport/pkg/activesupport-3.0.0.beta3.gem
Password:
Successfully installed i18n-0.3.7
Successfully installed tzinfo-0.3.20
Successfully installed memcache-client-1.8.2
Successfully installed activesupport-3.0.0.beta3
4 gems installed
Installing ri documentation for i18n-0.3.7...
Installing ri documentation for tzinfo-0.3.20...
Installing ri documentation for memcache-client-1.8.2...
Installing ri documentation for activesupport-3.0.0.beta3...
Installing RDoc documentation for i18n-0.3.7...
Installing RDoc documentation for tzinfo-0.3.20...
Installing RDoc documentation for memcache-client-1.8.2...
Installing RDoc documentation for activesupport-3.0.0.beta3...
[greg:rails] ls -al activemodel/pkg
total 72
drwxr-xr-x   3 greghelton  staff    102 Apr 22 01:19 .
drwxr-xr-x  11 greghelton  staff    374 Apr 22 01:19 ..
-rw-r--r--   1 greghelton  staff  33792 Apr 22 01:19 activemodel-3.0.0.beta3.gem
[greg:rails] sudo jgem install ./activemodel/pkg/activemodel-3.0.0.beta3.gem
Successfully installed activemodel-3.0.0.beta3
1 gem installed
Installing ri documentation for activemodel-3.0.0.beta3...
Installing RDoc documentation for activemodel-3.0.0.beta3...
[greg:rails] jirb

irb(main):013:0> require 'active_model'
=> true
irb(main):014:0> class Person                                       
irb(main):015:1>   include ActiveModel::Validations                 
irb(main):016:1>   validates_presence_of :first_name, :last_name    
irb(main):017:1>   attr_accessor :first_name, :last_name            
irb(main):018:1>   def initialize(first_name, last_name)            
irb(main):019:2>     @first_name, @last_name = first_name, last_name
irb(main):020:2>   end                                              
irb(main):021:1> end                                                
=> nil
irb(main):022:0> a = Person.new("Barney", "Rubble")
=> #
irb(main):023:0> a.valid?
=> true
irb(main):024:0>

Super!

Use SQL Relationally

2010-04-12T11:20:00.000-07:00

C. J. Date's intro video describing the relational model. The forty minute course intro is free and very helpful.

Clojure Is LISP

2010-04-10T08:26:00.000-07:00

Clojure 1.1 release candidate is available. clojure.lang.Repl is deprecated. Use clojure.main

cd dev/lib/clojure-1.1.0
java -cp .:clojure.jar:jline-0.9.94.jar jline.ConsoleRunner clojure.main

user=> (def r 5)
#'user/r
user=> r
5
user=> (+ r 3)
8
user=> (def clojure 'lisp)
#'user/clojure
user=> clojure
lisp
user=> (def s [5 6 7])
#'user/s
user=> s
[5 6 7]
user=> (first s)         
5
user=> (rest s) 
(6 7)
user=> (def t {"a" 1 "b" 2 "c" 3})
#'user/t
user=> (get t "a")
1
user=> (first t)
["a" 1]
user=> (def u {:a 1 :b 2 :c 3})   
#'user/u
user=> (get u :a)              
1
user=> (let [x 2] (+ x 8))
10
user=> (new BigDecimal 10)
10M
user=> (new BigDecimal 1) 
1M
user=> (new File "temp.clj")
java.lang.IllegalArgumentException: Unable to resolve classname: File (NO_SOURCE_FILE:61)
user=> (import 'java.io.File)
java.io.File
user=> (new File "temp.clj") 
#<File temp.clj>
user=> (def y ["one" "two"])       
#'user/y
user=> (def z (cons "zero" y))
#'user/z
user=> z
("zero" "one" "two")
user=> (cons "zero" ("one" "two")) 
java.lang.ClassCastException: java.lang.String cannot be cast to clojure.lang.IFn (NO_SOURCE_FILE:0)
user=> (cons "zero" '("one" "two"))    
("zero" "one" "two")
user=> (nth z 2)
"two"
user=> (new java.util.HashMap {"one" 1 "two" 2 "three" 3})
#
user=> (java.util.HashMap. {"one" 1 "two" 2 "three" 3})
#
(def cars ['Ford 'Chevy 'Dodge])
#'user/cars
user=> (rest cars)
(Chevy Dodge)
user=> (first cars)
Ford
user=> (first (rest cars))
Chevy
user=> (def broken (first (rest cars)))                 
#'user/broken
user=> broken
Chevy
user=> (def cars (cons 'GMC cars))
#'user/cars
user=> cars
(GMC Ford Chevy Dodge)
user=> (def stooges (sorted-set 'larry 'mo 'curly))
#'user/stooges
user=> stooges
#{curly larry mo}
user=> (first stooges)                             
curly
user=> (rest stooges)                              
(larry mo)
user=> (def stooges (sorted-map :a 'larry :b 'mo :c 'curly))
#'user/stooges
user=> (stooges :a)                                         
larry
user=>

Function Definition

(defn function-name doc-string? attr-map? [parameter-list]
(expressions))

user=> (defn add [a b] (+ a b)) 
#'user/add
user=> (add 1 2)
3
user=> (defn biggerthanabreadbox? [thing] (> thing 3))
#'user/biggerthanabreadbox?
user=> (biggerthanabreadbox? 5)                       
true
user=> (biggerthanabreadbox? 1)
false
user=> (defn total-cost [price quantity] 
   (* price quantity)) 
#'user/total-cost
user=> (total-cost 3 2)
6

More Examples

user=> (defstruct book :title :author) 
#'user/book
user=> (def b struct) 
#'user/b
user=> (def b (struct book "Alice in Wonderland" "Lewis Carroll"))
#'user/b
user=> (:title b)
"Alice in Wonderland"
user=> (defmulti prt class)     
#'user/prt
user=> (defmethod prt String [s]
(.write *out* s))        
#
user=> (prt "Clojure is Cool!")
Clojure is Cool!nil
user=> (derive ::bronze ::basic)
nil
user=> (derive ::silver ::basic) 
nil
user=> (derive ::gold ::premier)
nil
user=> (derive ::platinum ::premier)
nil
user=> (isa? ::bronze ::premier)
false
user=> (isa? ::gold ::premier)  
true

Testing Identity

2010-04-03T10:25:00.000-07:00

A quick review of hashCode(). The commonly stated rules are:
1. hashCode() must be overridden when equals() is overridden
2. when objects are equal then their hash codes should be as well

We begin with the the Car class that relies on default equality inherited from the Object class wherein the equals() method is simply a reference comparison.

package com.cars;
public class Car {
 private int vin; //Vehicle ID Number
 public Car(int vin) {
  this.vin = vin;
 }
 public int getVin() { 
  return vin;
 }
}

And we test this using Java assertions (a review of Java assertions never hurt).

package com.cars;
public class TestingIdentity {  
 public static void main(String[] args) {
  Car car1 = new Car(1);
  Car car2 = new Car(1);
  assert car1 != car2;       // line 6
  assert car1.equals(car2);  // line 7
}

On line 6 of TestingIdentity, we know the objects are not the same object but on line 7, two objects having the same values are unequal too so the assertion fails when we compile and run the code.

javac -sourcepath src -classpath ./build -d build src/com/cars/Car.java
javac -sourcepath src -classpath ./build -d build src/com/cars/TestingIdentity.java
java -ea -classpath ./build com.cars.TestingIdentity
Exception in thread "main" java.lang.AssertionError
 at com.cars.TestingIdentity.main(TestingIdentity.java:7)

In the semantics of our application, we would like instances having the same VIN to be equal. Let's write that code.

package com.cars;

public class Car {
 private int vin;
 public Car(int vin) {
  this.vin = vin;
 }
 public int getVin() { 
  return vin;
 }
 
 @Override
 public boolean equals(Object o) {
  if (o == null) 
   return false;
  if (this == o) 
   return true;
  if (o.getClass() != this.getClass())
   return false;
  Car car = (Car)o;
  if (car.getVin() == this.vin) 
   return true;
  return false;
 }
}

And when we run this code, we get no complaints from the line assert car1.equals(car2);. So, are we done? Well, we are always told that we must override hashCode() whenever we override equals(). Let's explore hashCode() to see why it must be overridden. The documentation of the HashSet.add() method states that the method "Adds the specified element to this set if it is not already present". Let's prove that failing to override hashCode() causes HashSet to fail to perform it's prescribed behavior.

package com.cars;
import java.util.Set;
import java.util.HashSet;
public class TestingIdentity {  
 public static void main(String[] args) {
  Car car1 = new Car(1);
  Car car2 = new Car(1);
  assert car1 != car2;       // line 8
  assert car1.equals(car2);  // line 9
  
  Set set = new HashSet();
  set.add(car1);
  set.add(car2);
  assert set.size() == 1;  // line 14
 } 
}

Because the objects are 'equal', we expect only one instance to be in the HashSet. When we run the code however, we get the trouble we've been looking for. The new assertion in the code above fails because the HashSet relies on hashCode() in its determination of whether the object already exists in the Set.

javac -sourcepath src -classpath ./build -d build src/com/cars/TestingIdentity.java
java -ea -classpath ./build com.cars.TestingIdentity
Exception in thread "main" java.lang.AssertionError
 at com.cars.TestingIdentity.main(TestingIdentity.java:14)

To attempt to solve this problem, we follow the admonition and override hashCode() in the Car class:

 @Override
 public int hashCode() {
  return vin;
 }

The code above now runs without violating the assertions because hashCode() is overridden so that whenever a.equals(b), then a.hashCode() == b.hashCode()

The solution is a little simplistic but it does work for the given problem. A better solution is to use org.apache.commons.lang.builder.HashCodeBuilder.

The Future of the Wave

2010-04-02T18:55:00.000-07:00

From MIT Media Lab and the creator of jQuery, we get some cool stuff for the browser.

eBay Scalability

2010-03-24T21:41:00.000-07:00

Discussing SQL with a friend a few days ago, it occurred to me that the design of some databases could be described as procedural instead of relational. These procedural databases do a few things well but such a database design is found to be a hindrance when the time comes to add new features to the application. That is the negative view but, this article makes the case for just such a design.

Point 4 in the article states"To scale at Digg they followed a set of practices very similar to those used at eBay. No joins, no foreign key constraints (to scale writes), primary key look-ups only, limited range queries, and joins were done in memory". (Note how much this design mirrors the design used in most AS/400 RPG applications.)

The article's point 2 directs the designer to restrict what the user can do and to have no intention of having a generic database. The article doesn't state that point 2 is prerequisite to point 4 but I think it must be. Such a design may sometimes be necessary but electing to omit normalization from the database design reduces the potential for extension of that database.

Both a relational design and the design used at Digg are legitimate but, as with all design decisions, there are trade-offs. The design can be generalized and thus extensible or it can be performance optimized and specialized to do fewer business functions with limited potential for reuse without redesign. To get both the generalized extensibility and the functionality optimized for critical performance requirements, consideration should be given to dividing the problem and solving it with two designs.

A quote from this article gives food for thought about when and how to address scalability:
Scalability is about how resource usage changes as units of work grow in number or size. Said another way, scalability is the shape of the price-performance curve, as opposed to its value at one point in that curve.

Size of MySQL Database and More

2010-03-22T16:44:00.000-07:00

Get the size of the xyz database

du -ch data/xyz/* | grep total
808K

Create a User and Grant Him Privileges

mysql> use xyz; 
Database changed

mysql> show tables;                                                                                                                                                                                                             
+------------------+
| Tables_in_xyz    |
+------------------+
| actor            | 
+------------------+
1 row in set (0.00 sec)

mysql> create user 'clerk'@'localhost' identified by 'aPassword';
Query OK, 0 rows affected (0.01 sec)

mysql> grant delete,insert,select,update on xyz.actor to 'clerk'@'localhost'; 
Query OK, 0 rows affected (0.00 sec)

Alternatively, Grant All

mysql> grant all on xyz.* to ’clerk’@'localhost';

Change the User's Password and the Necessary Subsequent Step

mysql> update mysql.user set password = Password('aPassword') where user = 'clerk'@'localhost'; 
Query OK, 1 row affected (0.00 sec)

mysql> flush privileges;
Query OK, 0 rows affected (0.04 sec)

Alternative for Setting Password

mysql> set password for 'clerk'@'localhost' = Password('aPassword');

Verify the User Exists

mysql> select user, host from mysql.user;

Verify Privileges Granted a User

mysql> select * from information_schema.table_privileges where GRANTEE = '''clerk''@''localhost''';
+-----------------------+---------------+--------------+------------+----------------+--------------+
| GRANTEE               | TABLE_CATALOG | TABLE_SCHEMA | TABLE_NAME | PRIVILEGE_TYPE | IS_GRANTABLE |
+-----------------------+---------------+--------------+------------+----------------+--------------+
| 'manager'@'localhost' | NULL          | xyz          | staff      | SELECT         | NO           | 
| 'manager'@'localhost' | NULL          | xyz          | actor_info | SELECT         | NO           | 
| 'manager'@'localhost' | NULL          | xyz          | actor_info | INSERT         | NO           | 
| 'manager'@'localhost' | NULL          | xyz          | actor_info | UPDATE         | NO           | 
| 'manager'@'localhost' | NULL          | xyz          | film_list  | SELECT         | NO           | 
| 'manager'@'localhost' | NULL          | xyz          | actor      | SELECT         | NO           | 
| 'manager'@'localhost' | NULL          | xyz          | actor      | INSERT         | NO           | 
| 'manager'@'localhost' | NULL          | xyz          | actor      | UPDATE         | NO           | 
| 'manager'@'localhost' | NULL          | xyz          | actor      | DELETE         | NO           | 
| 'manager'@'localhost' | NULL          | xyz          | payment    | SELECT         | NO           | 
+-----------------------+---------------+--------------+------------+----------------+--------------+
10 rows in set (0.00 sec)

Column Level Security

mysql> revoke all on xyz.staff from 'manager'@'localhost';
Query OK, 0 rows affected (0.01 sec)

mysql> grant select(staff_id, first_name, last_name, address_id, picture, email, 
store_id, active, username, last_update) on xyz.staff to 'manager'@'localhost';
Query OK, 0 rows affected (0.01 sec)

Quickest Way To Run a MySQL Command

mysql -t --user=ghelton --password=aPassword -e "select * from classicmodels.Orders;"

Google's Python Class

2010-03-21T19:46:00.000-07:00

Google's Python Class

MySQL FULLTEXT

2010-03-14T09:38:00.000-07:00

TEXT columns in a MySQL ISAM table can be searched using the MATCH keyword which is similar to LIKE.

Select Name, Description from Artists where match(Description) AGAINST ('American'); 

+------------------+-------------------------------------+
| Name             | Description                         |
|------------------+-------------------------------------+
| Ray Charles      | Unsurpassed American Musician       | 
+------------------+-------------------------------------+

Here's the Kicker
The results can be expanded with natural language capabilities by adding WITH QUERY EXPANSION to the AGAINST clause of the MATCH. The Buddy Holly record does not include the search word but because 'unsurpassed was in proximity to the searchword 'American' found in the Ray Charles record, the search results include records which have 'unsurpassed' as well.

Select Name, Description from Artists where match(Description) AGAINST ('American' WITH QUERY EXPANSION); 

+--------------------+-------------------------------------+
| Name               | Description                         |
|--------------------+-------------------------------------+
| Ray Charles        | Unsurpassed American Musician       | 
| Buddy Holly        | Buddy had unsurpassed promise.      | 
+--------------------+-------------------------------------+

Prereqs:

ALTER TABLE Artists ENGINE=MyISAM;
ALTER TABLE Artists ADD FULLTEXT (Description);

Objective C Project - See the Movie

2010-02-12T20:42:00.000-08:00

Unit testing Objective-C code in a 15 minute movie by Brett Schuchert - http://schuchert.wikispaces.com/tdd.objectivec.XCodeProjectSetup

Scientific American

2010-02-09T23:10:00.000-08:00

An article in Scientific American posits the idea that the extended helpless state of human infants compared to other animals is the catalyst that allows humans to develop the skills to elicit assistance and to work with others.

Often, components that do less are more powerful. REST has six operations, SQL four and MQ two. LISP uses only nine words to define the whole of computing. Most would agree that additional features and responsibilities in these applications would be detrimental. Developers should use the same care to avoid overloading a class with more than one responsibility.

OO is all about responsibility assignment:

Class Responsibility Collaboration (CRC) cards, 1989 by Beck and Cunningham

Single Responsibility Principle, 1996 by Bob Martin

GRASP (general responsibility assignment software patterns), 1999 by Craig Larman

Responsibilities are not the sort described by "allow the user to enter and save customer information" (that's the use case) but are discrete, divided among the application layers (presentation, domain and persistence) and assigned at the component level.

HTTP & REST & SOAP

2010-02-09T08:51:00.000-08:00

HTTP - Hypertext Transfer Protocol
POST - submits data to be processed (e.g., from an HTML form) to the identified resource
GET - requests a representation of the current state of this resource
PUT - (idempotent) create or update this resource with the accompanying representation
DELETE - (idempotent) remove this resource
HEAD - like GET but only response headers are returned

REST - Representational State Transfer
a style of software architecture for distributed hypermedia systems

SOAP - Simple Object Access Protocol. Performs Remote Procedure Calls (RPC) based on information in XML documents.

Atom Publishing Protocol (based on REST)
POST - create content
GET - retrieve content
PUT - edit content
DELETE - delete content

Another Quote

2010-02-01T17:20:00.001-08:00

“The physicist's greatest tool is his wastebasket.” -- Albert Einstein

Things Go Better With CSS

2010-01-28T21:17:00.000-08:00

Scrolling coke can

Open Source Tips

Superb Spring Info

Movie Theater Engagement Database

MySQL Database for Cookbook

Spring Persistence with Hibernate

StreamReaderHelper.java

Test Using Apache HTTPComponents

Ruby Hash

Uniform Level of Abstraction

Mockito

Tweet

Processing.js Horror

Beginner's Mind

Two Lists

Long time ago, I memorized 2 lists of 4 items each

jQuery Selectors

Javascript - One Image, Two Buttons

Clojure Lists, Maps and Sets

Old School JDBC-ODBC

Postgresql Server Management

Clojure recursion and recur

Top 10 Vulnerabilities

Baseball Chat

styles.css

chat.html

post_message.php

Motivation

Maven Archetypes on Webtide

First Evidence

Neanderthals

CoffeeScript

JavaScript Web Applications

Violet UML Editor

Why Does This Work?

Now, a slightly different version shows the accessor is called implicitly when using the field name

Manning's New Book - Entity Framework 4 in Action

60 Minutes

SQLite and ANT

Geronimo Server

Trader Joe’s

Who Makes This Stuff Up?

A Little Python

An Engineer

Tapestry 5

My Opinion

Naked Objects

DeMarco

Using Homebrew to Install Postgresql

IN-N-OUT Burger Coming Soon to Frisco TX

SOLID Ruby

Hello JSF

C++ Cookbook

Code Metrics

Scala in Stalled

Remember Jython?

TestClass.java

mypy.py

Terminal

Interactive Swing

Gradle

Metrics

Gray Hat Python

Open Source Integration

SQL Server XML Support

Monofesto

Best Job Ever

OSGi for Low Coupling and High Cohesion

src/META-INF/MANIFEST.MF

ANT build.xml for the Activator

Java Code for the Message Producer

src/META-INF/MANIFEST.MF

ANT build.xml for the Producer

Java Code for the Consumer

src/META-INF/MANIFEST.MF

build.xml for the Consumer

It's Showtime!

Charity

Getting to Know Threads

Magic for Rails

JUnit, DateFormat, Calendar and ANT