apache ant ivy conditionally build a module - ivy

Question

I have a usecase where in I had to create a new module in out project. Our main project has multiple modules and each module is a java project. We are using ivy for dependency resolution. Now the probkem is that in the new module , I had to use java 1.7 API (WatchService) which is not there in java 1.6. Now in build.xml I can check for the java version and accordingly build this new module depending on the java -version. The problem comes in ivy.xml of or main web project where I have to mention the jar file of the new module as a dependency to include in the generated war file. If the java version is 1.7 , then in that case problem wont be there as the jar will be build and the its dependency will be resolved. the problem arises when the java version is 1.6. The jar file wont be created and when its time to generate the war file, ivy wont be able to resolve the dependency as the jar file is not there. Maybe the approach that I am trying to apply here is not fine. Please advice me on how to work around this particular use case.
rampal

Answer 1

In ivy you can use configurations to maintain different sets of depenedencies:
<ivy-module version="2.0">
<info organisation="com.myspotontheweb" module="demo"/>
<configurations>
<conf name="compile_jdk7" description="Java JDK7 compile dependencies"/>
<conf name="compile_jdk6" description="Java JDK6 compile dependencies"/>
</configurations>
<dependencies>
<!-- JDK7 dependencies -->
<dependency org="org.myorg" name="module1" rev="latest.integration" conf="compile_jdk7->default"/>
<dependency org="org.myorg" name="module2" rev="latest.integration" conf="compile_jdk7->default"/>
<dependency org="org.myorg" name="module3" rev="latest.integration" conf="compile_jdk7->default"/>
<!-- JDK6 dependencies -->
<dependency org="org.myorg" name="module1" rev="latest.integration" conf="compile_jdk6->default"/>
<dependency org="org.myorg" name="module3" rev="latest.integration" conf="compile_jdk6->default"/>
</dependencies>
</ivy-module>
and in the build file use a condition task to choose which configuration is used at run-time to populate the classpath, using the cachepath task:
<project name="demo" default="compile" xmlns:ivy="antlib:org.apache.ivy.ant">
<condition property="compile.config" value="compile_jdk7">
<equals arg1="${ant.java.version}" arg2="1.7"/>
</condition>
<condition property="compile.config" value="compile_jdk6">
<equals arg1="${ant.java.version}" arg2="1.6"/>
</condition>
<target name="resolve" description="Use ivy to resolve classpaths">
<ivy:cachepath pathid="compile.path" conf="${compile.config}"/>
</target>
<target name="compile" depends="resolve" description="Compile code">
<javac ...... classpathref="compile.path"/>
</target>
</project>