Dynamically generate JAR files based on package name with ANT

Question

My current build file has the following repetitive tasks:

<jar jarfile="${build.lib}/${prefix}-foo.jar">
    <fileset dir="${build.classes}">
     <include name="com/a/c/foo/**"/>
    </fileset> 
</jar>
<jar jarfile="${build.lib}/${prefix}-bar.jar">
    <fileset dir="${build.classes}">
     <include name="com/a/c/bar/**"/>
    </fileset>
</jar>

... etc. The issue is that the build.xml must be modified for each new package or for each new sub-project. This is a frequent occurrence where I work.

I would like to replace this with logic that will dynamically generate the JARs and their file names based off of a "root" package. So, for example, I could set the root package to be com/a/c, and all packages directly under that package would get their own JAR. Note that all packages under "foo" or "bar" would just be part of "foo.jar" or "bar.jar".

I looked up for loop logic tasks for ANT. I found one in each ant-contrib and JWare/AntXtras, but I could not get either to work as desired.

Answer 1

I don't know about looping over and finding all package names, but you could use a macro to avoid code duplication.

I haven't tried this, but it could work

<macrodef name="build_jar">
    <attribute name="name"/>
    <sequential>
        <jar jarfile="${build.lib}/${prefix}-@{name}.jar">
            <fileset dir="${build.classes}">
                <include name="com/a/c/@{name}/**"/>
            </fileset>
        </jar>
    </sequential
</macrodef>

<target name="build_foo">
    <build_jar name="foo"/>
</target>

<target name="build_bar">
    <build_jar name="bar"/>
</target>

Answer 2

How about this:

<project name="dynjar" default="jar" basedir=".">
    <property name="build.classes" value="${basedir}/classes"/>
    <property name="build.lib" value="${basedir}/lib"/>
    <property name="prefix" value="prefix"/>
    <property name="root" value="com/a/c"/>

    <target name="jar">
        <!-- ${ant.file} is the name of the current build file -->
        <subant genericantfile="${ant.file}" target="do-jar">

            <!-- Pass the needed properties to the subant call. You could also use
                 the inheritall attribute on the subant element above to pass all
                 properties. -->
            <propertyset>
                <propertyref name="build.classes"/>
                <propertyref name="build.lib"/>
                <propertyref name="prefix"/>
                <propertyref name="root"/>
            </propertyset>

            <!-- subant will call the "do-jar" target for every directory in the
                 ${build.classes}/${root} directory, making the subdirectory the
                 basedir. -->
            <dirset dir="${build.classes}/${root}" includes="*"/>
        </subant>
    </target>

    <target name="do-jar">
        <!-- Get the basename of the basedir (foo, bar, etc.) -->
        <basename file="${basedir}" property="suffix"/>

        <jar jarfile="${build.lib}/${prefix}-${suffix}.jar">
            <fileset dir="${build.classes}">
                <include name="${root}/${suffix}/**"/>
            </fileset>
        </jar>
    </target>
</project>