Why classpath refid (newbie)?

[Peter Tilm]

Hi,
why is the classpath refid used in the target "compile". Is it to include the jars? What exactly does the pathelement path? does it include the servlet.jar e.g.
------
<path id="project.class.path">
<fileset dir="./WEB-INF/lib/">
<include name="**/*.jar"/>
</fileset>
<pathelement path="${src.dir}"/>
<pathelement path="${servlet.jar}"/>
</path>
<target name="compile">
<javac srcdir="${src.dir}"
destdir="${build.dir}"
debug="on"
deprecation="on">
<include name="**/*.java"/>
<classpath refid="project.class.path"/>
</javac>
</target>
------
thanks,
Peter

[Lasse Koskela]

Using a refid is a means to avoid duplicating the same set of classpath entries in multiple places in a build file.
I.e.

<path id="project.class.path">
  <fileset dir="./WEB-INF/lib/">
    <include name="**/*.jar"/>
  </fileset>
  <pathelement path="${src.dir}"/>
  <pathelement path="${servlet.jar}"/>
</path>
<target name="foo">
  <foo>
    <classpath refid="project.class.path"/>
  </foo>
</target>
<target name="bar">
  <bar>
    <classpath refid="project.class.path"/>
  </bar>
</target>
<target name="xyz">
  <zyx>
    <classpath refid="project.class.path"/>
  </bar>
</target>

instead of

<target name="foo">
  <classpath>
    <fileset dir="./WEB-INF/lib/">
      <include name="**/*.jar"/>
    </fileset>
    <pathelement path="${src.dir}"/>
    <pathelement path="${servlet.jar}"/>
  </classpath>
</target>
<target name="bar">
  <classpath>
    <fileset dir="./WEB-INF/lib/">
      <include name="**/*.jar"/>
    </fileset>
    <pathelement path="${src.dir}"/>
    <pathelement path="${servlet.jar}"/>
  </classpath>
</target>
<target name="xyz">
  <classpath>
    <fileset dir="./WEB-INF/lib/">
      <include name="**/*.jar"/>
    </fileset>
    <pathelement path="${src.dir}"/>
    <pathelement path="${servlet.jar}"/>
  </classpath>
</target>

Now which do you think is better when you need to add some .jar file into the compilation classpath...
[ December 11, 2003: Message edited by: Lasse Koskela ]