FYI: Ant-Netbean Dependency Issues & The Fix

**angryboy** · 06-05-2009, 09:53 PM

There seems to be a problem w/ ant, that it can't recompile those classes that depend on an interface which has changed.
To illustrate:

Java Code:

public class Test implements TestInterface{
  public static void main(String[] args){
    System.out.println(VALUE);
    System.out.println(NAME);
    System.out.println(obj);
  }
}

Java Code:

public interface TestInterface {
  int VALUE = 5;
  String NAME = "FOO";
  Object obj = null;
}

the build file:

Java Code:

  <target name="compile" depends="init" description="Compiles src files.">
    <mkdir dir="${classes.dir}"/>
    
    <depend srcdir="${src.dir}" destdir="${build.dir}" 
      cache=".depcache" closure="true">
        <include name= "**/*.java"/>    
    </depend>

    <javac srcdir="${src.dir}" destdir="${classes.dir}"
      deprecation="true" optimize="true" fork="true"/>
  </target>

First run:

Java Code:

A:\>ant clean run
Buildfile: build.xml
init:
clean:
init:
compile:
    [mkdir] Created dir: A:\build\classes
    [javac] Compiling 2 source files to A:\build\classes
run:[b]
     [java] 5
     [java] FOO
     [java] null
[/b]
BUILD SUCCESSFUL
Total time: 8 seconds
A:\>

Now edit the interface and recompile

Java Code:

public interface TestInterface {
  int VALUE = 99;
  String NAME = "BAR";
  Object obj = "Hello World!";
}

Java Code:

A:\>ant run
Buildfile: build.xml
init:
compile:[b]
   [depend] The class classes.Test in file A:\build\classes\Test.class is out of
 date due to TestInterface but has not been deleted because its source file could
 not be determined[/b]
    [javac] Compiling 1 source file to A:\build\classes
run:[b]
     [java] 5
     [java] FOO
     [java] Hello World!
[/b]
BUILD SUCCESSFUL
Total time: 6 seconds
A:\>

The Fix:
Use an external lib: JMake (was JavaMake).
src only: The jmake utility — Project Kenai
bin attached below...

Java Code:

  <target name="compile" depends="init" description="Compiles src files.">
    <mkdir dir="${classes.dir}"/>
    
    <taskdef name="jmake" classpath="jmake.jar"
      classname="com.sun.tools.jmake.ant.JavaMake"/>
      
    <jmake srcdir="${src.dir}" destdir="${classes.dir}"
      deprecation="true" optimize="true" fork="true"
      pdbFilename=".depcache/jmake.pdb"
      failondependentjar="true"/>
  </target>

On second run after "ant clean run" using jmake

Java Code:

A:\>ant run
Buildfile: build.xml
init:
compile:
    [jmake] Jmake version 1.3.5
    [jmake] Opening project database...  Done.
    [jmake] Compiling 1 source file to A:\build\classes
    [jmake] Checking TestInterface
    [jmake] Compiling 1 source file to A:\build\classes
    [jmake] Checking Test
    [jmake] Writing project database...  Done.
run:[b]
     [java] 99
     [java] BAR
     [java] Hello World!
[/b]
BUILD SUCCESSFUL
Total time: 10 seconds
A:\>

Now what if this is used on netbeans, would it be faster not having to call "ant clean" on every build?
I'll leave that test to IDE users...