[@699]
My Predictions Jeremy asked me about my predictions for 2006, so I obliged:

[@378] Joyeux Noël

[@586]
toString Velocity Template

I'm using the excellent GenereateToString plugin to automatically create toString() methods in IDEA.

I've modified the default Velocity template as follows:

/**
* Returns a string representation of the object.
*
* @return A string representation of the object.
*/
public final String toString() {
final StringBuffer sb = new StringBuffer(super.toString());
#set ($i = 0)
#foreach ($member in $members)
#if (!$member.modifierStatic)
#if ($i == 0)
sb.append("[ ##
#else
sb.append(", ##
#end
#if ($member.string)
$member.name.replaceFirst("_", "") -> '")##
#else
$member.name.replaceFirst("_", "") -> ")##
#end
#if ($member.primitiveArray)
.append($member.name == null ? "null" : "");
sb.append('{');
for (int i = 0; $member.name != null && i < $member.name .length; ++i)
sb.append(i == 0 ? "" : ", ").append($member.name[i]);
sb.append('}');
#elseif ($member.objectArray)
.append($member.name == null ? "null" : Arrays.asList($member.name).toString());
#elseif ($member.string)
.append($member.accessor).append('\'');
#else
.append($member.accessor);
#end
#set ($i = $i + 1)
#end
#end
#if ($members.size() == 0)
sb.append("{}");
#else
sb.append(" ]");
#end
return sb.toString();
}

Here's an example of the code it automatically generates:

public class Test
{
  private String _name;
  private int _port;
  private String _url;
  private String[] _validIPs;
  // …

  /**
  * Returms a string representation of the object.
  *
  * @return A string representation of the object.
  */
  public final String toString()
  {
    final StringBuffer sb = new StringBuffer(super.toString());
    sb.append("[ name -> '").append(_name).append('\'');
    sb.append(", url -> '").append(_url).append('\'');
    sb.append(", port -> ").append(_port);
    sb.append(", validIPs -> ").append((_validIPs == null) ? "null" : Arrays.asList(_validIPs).toString());
    sb.append(" ]");

    return sb.toString();
  }
}

Here's a sample of what it returns:

Test@126b249[ name -> 'Test', url -> 'http://www.test.com', port -> 80, validIPs -> [127.0.0.1, localhost] ]

Overall not that many modifications from the default template:

• The default template uses name=value, I use name -> value which I find more legible.
• The default template prepends the class name, I prepend the super's toString() representation.
• I also remove the underscore in front of field names, once again for legibility.
• Finally, I added some javadoc comments.

[@687]
Array Initialization

public class Example {
  public Boolean flags[] = new Boolean[4];
  public static void main(String[] args) {
    Example ex = new Example();
    System.out.println( "Flag 1 is " + ex.flags[1] );
  }
}

Yes, Flag 1 is null. I can't believe I forgot that.

[@151]

The Pulse

Erik's Pulse has been published.

[@634]

[@021]

The Pulse

Erik's Pulse has been published.

[@570]

Logging Packages with Log4J

I was looking for a way to log a specific package to its own file using Log4J. Took me a while to figure it out, but here's what I came up with in my log4j.xml file:

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE log4j:configuration SYSTEM "log4j.dtd">
<log4j:configuration xmlns:log4j="http://jakarta.apache.org/log4j/" debug="false">

<!-- Main Rolling Log (by Size) -->
<appender name="R" class="org.apache.log4j.RollingFileAppender">
<param name="File" value="main.log"/>
<param name="Append" value="true"/>
<param name="MaxFileSize" value="10MB"/>
<param name="maxBackupIndex" value="10"/>
<layout class="org.apache.log4j.PatternLayout">
<param name="ConversionPattern" value="[%d{yyyy-MM-dd HH:mm:ss}] [%p] %m%n"/>
</layout>
</appender>

<!-- MyPackage Rolling Log -->
<appender name="P" class="org.apache.log4j.RollingFileAppender">
<param name="File" value="mypackage.log"/>
<param name="Append" value="true"/>
<param name="MaxFileSize" value="10MB"/>
<param name="maxBackupIndex" value="10"/>
<layout class="org.apache.log4j.PatternLayout">
<param name="ConversionPattern" value="[%d{yyyy-MM-dd HH:mm:ss}] [%p] %m%n"/>
</layout>
</appender>

<!-- MyPackage Logger -->
<logger name="net.thauvin.erik.mypackage" additivity="false">
<appender-ref ref="P"/>
</logger>

<!-- Print only messages of priority INFO or above in the com.example package -->
<category name="com.example">
<priority value="info"/>
</category>

<!-- Root (Default) Logging -->
<root>
<priority value="fatal"/>
<appender-ref ref="R"/>
</root>

</log4j:configuration>

Incidentally, Log4j 1.2.13 was just released.