<change id="ElementUtilities.findSubtypes">

             <api name="general"/>

             <summary>Added ElementUtilities.findSubtypes</summary>

             <version major="0" minor="59"/>

             <date day="21" month="4" year="2010"/>

             <author login="jlahoda"/>

             <compatibility addition="yes" binary="compatible" deletion="no" deprecation="no" modification="no" semantic="compatible" source="compatible"/>

             <description>

                 Added <code>ElementUtilities.findSubtypes</code> method, which

                 returns a all subtypes of given types.

             </description>

             <class package="org.netbeans.api.java.source" name="ElementUtilities"/>

             <issue number="184168"/>

        </change>

import java.io.IOException;

import java.net.URL;

import java.util.Collection;

import java.util.Map;

import java.util.Set;

import org.netbeans.modules.java.source.tasklist.TasklistSettings.DependencyTracking;

import org.netbeans.modules.java.source.util.FindUsagesUtils;

import org.openide.filesystems.FileObject;

import org.openide.util.Exceptions;

    /**

     * Finds all subtypes of given types in all known source roots that depend on the current source root.

     *

     * @param handles types for which the subtypes should be found

     * @return all found subtypes for the given types, classified by source root and original type. <code>null</code> may be returned if current the task is canceled.

     * @since 0.59

     */

    public Map<URL, Map<ElementHandle<TypeElement>, Set<ElementHandle<TypeElement>>>> findSubTypes(Collection<? extends ElementHandle<TypeElement>> handles) {

        FileObject owner = info.getClasspathInfo().getClassPath(ClasspathInfo.PathKind.SOURCE).findOwnerRoot(info.getFileObject());

        if (owner == null) {

            return Collections.emptyMap();//TODO: log?

        }

        Map<URL, Map<ElementHandle<TypeElement>, Set<ElementHandle<TypeElement>>>> result = new HashMap<URL, Map<ElementHandle<TypeElement>, Set<ElementHandle<TypeElement>>>>();

        try {

            if (FindUsagesUtils.findUsages(owner.getURL(), new LinkedList<ElementHandle<TypeElement>>(handles), result, false, true, false, DependencyTracking.ENABLED) == null) {

                return null;

            }

        } catch (IOException ex) {

            //should not normally happen:

            Exceptions.printStackTrace(ex);

        }

        return result;

    }