Java 仅在架构更改时使用XJCFacade创建类

如何在build.xml中编辑上述Ant任务，以确保仅当名为dev.xsd的xsd被修改时，上述java脚本（XJCFacade）才能运行

我还想确保javac和jar只在java（xjcafacade）运行时运行

<target name="buildBbastJarFromXsd">
    <echo message="Generating jar from xsd for RestService"/>
    <java classname="com.sun.tools.internal.xjc.XJCFacade">
        <arg value="-d" />
        <arg value="${dev.location}"/>
        <arg "${dev.location}/path/dev.xsd" />
    </java>
    <javac srcdir="${dev.location}" destdir="${dev.location}"
        debug="on" includeantruntime="false"
    >
        <classpath refid="dev.classpath"/>
    </javac>
    <jar
        destfile="${dev.location}/WebContent/WEB-INF/rest.jar"
        basedir="${bbct.location}"
        includes="**/*.class"
    />
</target>