Java pre compiler ... well nearly

Ant
For simple needs, Ant can be used to do substitution in your sources.

We insert into the code a special tag to delimit code that need to be stripped by the Ant script. Let's say we use //@STARTDEBUG@// and //@ENDDEBUG@//.

package academic.howto;

import javax.swing.JFrame;

public class Example {

public static void main(String args[]){

JFrame f = new JFrame();

f.setSize(300,200);

f.setVisible(true);

f.setTitle("HowTo");

//@STARTDEBUG@//

f.setTitle(f.getTitle() + " DEBUG version");

//@ENDDEBUG@//

f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

}

}

If you execute this code, the JFrame title will have the word "DEBUG" appended to it.

The Ant script to remove the debugging code is :
<project default="buildme">

   <target name="compileprod">
    <copy todir="../out" includeEmptyDirs="false">
    <filterchain>
            <tokenfilter>
            <replacestring from="//@STARTDEBUG@//" to="/*" />
            <replacestring from="//@ENDDEBUG@//" to="*/" />
            </tokenfilter>
    </filterchain>
        <fileset dir=".">
          <include name="**/*.java" />
       </fileset>
    </copy>

    <javac srcdir="../out" />
   </target>

   <target name="compiledebug">
     <javac srcdir="." />
   </target>

  
   <target name="buildme" depends="compileprod" />
</project>



After running this script, the source (in the ..\out directory)

package academic.howto;

import javax.swing.JFrame;

public class Example {

  public static void main(String args[]){
    JFrame f = new JFrame();
    f.setSize(300,200);
    f.setVisible(true);
    f.setTitle("HowTo");
    /*
    f.setTitle(f.getTitle() + " DEBUG version");
    */
    f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
  }
}

Only disadvantage is a few more minutes to compile but that is small trade off for a better runtime code - with less logging etc

http://www.rgagnon.com/javadetails/java-0130.html
this is another method ...have a class with a single static final bool and use if statements ... compiler automatically optimizes. CAUTION:this will work for a single project/ jar. if the variable ( public static final boolean RELEASE = true; ) is in another jar then javac will not optimize as you can replace the jars with the var set to false... for big applications might work if each package has the debug class and care is taken to reference only that.



CODE:

public class Debug {
  public static final boolean RELEASE = true;
  }

In your source, when you need some debugging codes, you included them in
 a if statement like 

if (Debug.RELEASE) {
   System.out.println("The value of i is " + i);
}

During compilation, since Debug.RELEASE is always true, the code will be present. In the production environment, the Debug class looks like this:

public class Debug {
  public static final boolean RELEASE = false;
  }

When compiling in that environment, the debugging code will be absent from the class file since Debug.release is always false.

REFERENCE:

rgagnon.com/..java-0164.html

rgagnon.com/..java-0130.html

sleep.exe, pause a batch program for specified time

when you need to sleep a while when using a batch program etc

http://hp.vector.co.jp/authors/VA007219/sleep/sleep.html sleep.vbs and v1/sleep.exe works with XP and win7 copied to system32 folder so can call it from anywhere






http://unattended.msfn.org/unattended.xp/view/web/10/ does not work on

java setting multiple system properties via command line options

if you want to set system properties when you invoke java (vs setting them in the system before you start java/ command prompt) can do so with the -D option to java.exe or javaw.exe

You do this for each property.


Lets assume your command line to start jva initially looks like:
java org.mypack.Main

 So if you need to set to properties
usePort=2322
factoryClass=org.mypack.net.Factory1

Then the new command line will be:

java -DusePort=2322 -DfactoryClass=org.mypack.net.Factory1 org.mypack.Main

Pretty obvious except I was not sure if I need to put a ; between properties or have multiple -D

For those using an IDE:
See image - remember these are VM options (VM arguments) and not program arguments
(Click image for full size)

How to : make a link in blogger

you can select a URL and make a link by clicking the link button

make sure your in the compose mode



first a URL



http://tusharkapila.blogspot.com/2008/05/s.html <-- Link made



or select some text and then click the link button, then enter the link address or email id



My site



Video:


(best view in full-screen, no audio)

safe-pc

A safe pc means a happy user. I use avast and super anti-malware protection. so do not just use a condom (must do that too) but protect your electronics gear too!

Thank you guys, and I hope you have enough business/ professional/ paid home users like me to constantly update and improve.