For multi-project builds, a common technique allows for importing build file pieces that reference what each project builds, called "artifacts:"

File: artifact.xml

	<project name="project-artifact"> <artifact id="art.project.jar" target="jar" name="project.jar" artifact="exports/myproject.jar" policyRef="policy"> <src> <include name="src/java/**" /> <exclude name="src/java/**/package.html" /> </src> <depends name="build"> <library refid="lib.log4j.1.2.7" /> <library id="lib.project-jar.xalan" org="apache"> <lib-entry group="xerces" name="xmlParserApis" version="2.6.2" /> <lib-entry group="xalan" name="xalan" version="2.5.0" /> </library> </depends> <depends name="test"> <library refid="lib.log4j.1.2.7" /> <library refid="lib.junit.3.8.1" /> <library refid="lib.project-jar.xalan" /> <lib-entry org="apache" group="xerces" name="xercesImpl" version="2.6.2" /> </depends> </artifact> </project>

File: build.xml

	<project name="project"> <import file="artifact.xml" /> : <target name="jar" depends="compile"> <jar destfile="${artifact.project.jar}" basedir="work/classes" /> </target> <target name="compile"> <mkdir dir="work/classes" /> <javac destdir="work/classes"> <srcpath> <fileset refid="fileset.artifact.project.jar" /> </srcpath> <classpath refid="path.art.project.jar.build" /> </javac> </target> </project>

Artifacts help the project describe what it generates, but it also tells other projects how it gets generated, and where to find that generated file.

This topic is fully covered in the Subprojects discussion.