Generate manifest class-path from <classpath> in Ant

Question

In the build file below, the jar target refers to the jar.class.path property for the manifest class-path. The compile target refers to project.class.path

There is redundancy here, because jar.class.path and project.class.path are very similar. They must be both updated when libraries are added, which can be a pain if the list of libraries gets very long. Is there a better way? Any solution must be cross-platform and always use relative paths.

Edit:
It should generate the JAR classpath from a fileset and not the other way around, so I can use wildcards to e.g. include all JAR files in a directory.

<?xml version="1.0"?> <project name="Higgins" default="jar" basedir=".">      <property name="jar.class.path" value="lib/forms-1.2.0.jar lib/BrowserLauncher.jar"/>      <path id="project.class.path">       <pathelement location="build"/>       <fileset dir="lib">         <include name="forms-1.2.0.jar"/>         <include name="BrowserLauncher.jar"/>       </fileset>     </path>      <target name="prepare">         <mkdir dir="build"/>     </target>      <target name="compile" depends="prepare" description="Compile core sources">         <javac srcdir="src"                includes="**"                destdir="build"                debug="true"                source="1.5">           <classpath refid="project.class.path"/>         </javac>     </target>      <target name="jar" depends="compile" description="Generates executable jar file">         <jar jarfile="higgins.jar">             <manifest>                 <attribute name="Main-Class" value="nl.helixsoft.higgins.Main"/>                 <attribute name="Class-Path" value="${jar.class.path}"/>             </manifest>             <fileset dir="build" includes="**/*.class"/>                         <fileset dir="src" includes="**/*.properties"/>                  </jar>     </target>  </project> 

Answer 1

<path id="build.classpath">   <fileset dir="${basedir}">      <include name="lib/*.jar"/>   </fileset> </path>  <pathconvert property="manifest.classpath" pathsep=" ">   <path refid="build.classpath"/>   <mapper>     <chainedmapper>        <flattenmapper/>        <globmapper from="*.jar" to="lib/*.jar"/>     </chainedmapper>   </mapper> </pathconvert>  <target depends="compile" name="buildjar">   <jar jarfile="${basedir}/${test.jar}">      <fileset dir="${build}" />      <manifest>        <attribute name="Main-Class" value="com.mycompany.TestMain"/>        <attribute name="Class-Path" value="${manifest.classpath}"/>      </manifest>  </jar> </target> 

For further information check out this article.

Answer 2

Assuming Ant 1.7 or above, you can use the manifestclasspath task.

<path id="dep.runtime">     <fileset dir="./lib">         <include name="**/*.jar" />     </fileset> </path> <property name="dep_cp" value="${toString:dep.runtime}" />  <target name="default">     <manifestclasspath property="manifest_cp" jarfile="myjar.jar">         <classpath refid="dep.runtime" />     </manifestclasspath>     <echo message="Build Classpath: ${dep_cp}" />     <echo message="Manifest Classpath: ${manifest_cp}" /> </target>