Question

Is there an Ant API for reading and ant build.xml and retrieving elements from it? Specifically I want to be able to retrieve the values in a path element and be able to walk all of the elements in the path.

My purpose is to retrieve a given path and ensure that it is referenced correctly in a manifest, so that the build and the manifest match when the product goes out to production.

EDIT: Regarding the responses (and thank you for them) to use an XML API, the problem is that the build file as currently constructed is more complex than that. Namely the classpath references a different classpath and includes it and the elements referenced in the classpath are themselves defined in a properties file, so there is too much of the Ant API to reasonably recreate.

Answer 1

You can use the ProjectHelper class to configure your project with a buildfile. If the path you want to check is contained in a reference, then you can just get the reference from the project by its ID.

For example, if you have something like this in your build.xml:

<path id="classpath">
    <fileset dir="${basedir}/lib" includes="*.jar"/>
</path>

Then you can get the Path reference with the following code:

import java.io.File;

import org.apache.tools.ant.Project;
import org.apache.tools.ant.ProjectHelper;
import org.apache.tools.ant.types.Path;

public class Test {
    public static void main(String[] args) throws Exception {    
        Project project = new Project();
        File buildFile = new File("build.xml");
        project.init();
        ProjectHelper.configureProject(project, buildFile);

        Path path = (Path) project.getReference("classpath");
     }
}

Note that ProjectHelper.configureProject is deprecated in ant 1.6.2, but not in 1.7.