Ant example source code file (AntClassLoaderDelegationTest.java)

This example Ant source code file (AntClassLoaderDelegationTest.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Ant tags/keywords

antclassloader, antclassloader, antclassloaderdelegationtest, classloader, io, list, net, network, parentloader, path, path, project, string, test_resource, test_resource, url, url, util

The AntClassLoaderDelegationTest.java source code

/*
 *  Licensed to the Apache Software Foundation (ASF) under one or more
 *  contributor license agreements.  See the NOTICE file distributed with
 *  this work for additional information regarding copyright ownership.
 *  The ASF licenses this file to You under the Apache License, Version 2.0
 *  (the "License"); you may not use this file except in compliance with
 *  the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 */

package org.apache.tools.ant;

import java.io.File;
import java.io.IOException;
import java.net.URL;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.Enumeration;
import java.util.List;
import junit.framework.TestCase;
import org.apache.tools.ant.Project;
import org.apache.tools.ant.types.Path;
import org.apache.tools.ant.util.FileUtils;

/**
 * Test case for ant class loader
 *
 */
public class AntClassLoaderDelegationTest extends TestCase {

    /** Instance of a utility class to use for file operations. */
    private static final FileUtils FILE_UTILS = FileUtils.getFileUtils();

    private Project p;

    public AntClassLoaderDelegationTest(String name) {
        super(name);
    }

    public void setUp() {
        p = new Project();
        p.init();
    }

    /** Sample resource present in build/testcases/ */
    private static final String TEST_RESOURCE
        = "apache/tools/ant/IncludeTest.class";
    
    public void testFindResources() throws Exception {
        // This path should contain the class files for these testcases:
        String buildTestcases = System.getProperty("build.tests");
        assertNotNull("defined ${build.tests}", buildTestcases);
        assertTrue("have a dir " + buildTestcases,
                   new File(buildTestcases).isDirectory());
        Path path = new Path(p, buildTestcases + "/org");
        // A special parent loader which is not the system class loader:
        ClassLoader parent = new ParentLoader();
        // An AntClassLoader which is supposed to delegate to
        // the parent and then to the disk path:
        ClassLoader acl = new AntClassLoader(parent, p, path, true);
        // The intended result URLs:
        URL urlFromPath = new URL(
            FILE_UTILS.toURI(buildTestcases) + "org/" + TEST_RESOURCE);
        URL urlFromParent = new URL("http://ant.apache.org/" + TEST_RESOURCE);
        assertEquals("correct resources (regular delegation order)",
            Arrays.asList(new URL[] {urlFromParent, urlFromPath}),
            enum2List(acl.getResources(TEST_RESOURCE)));
        acl = new AntClassLoader(parent, p, path, false);
        assertEquals("correct resources (reverse delegation order)",
            Arrays.asList(new URL[] {urlFromPath, urlFromParent}),
            enum2List(acl.getResources(TEST_RESOURCE)));
    }

    public void testFindIsolateResources() throws Exception {
        String buildTestcases = System.getProperty("build.tests");
        assertNotNull("defined ${build.tests}", buildTestcases);
        assertTrue("have a dir " + buildTestcases,
                   new File(buildTestcases).isDirectory());
        Path path = new Path(p, buildTestcases + "/org");
        // A special parent loader which is not the system class loader:
        ClassLoader parent = new ParentLoader();

        URL urlFromPath = new URL(
            FILE_UTILS.toURI(buildTestcases) + "org/" + TEST_RESOURCE);
        AntClassLoader acl = new AntClassLoader(parent, p, path, false);
        acl.setIsolated(true);
        assertEquals("correct resources (reverse delegation order)",
            Arrays.asList(new URL[] {urlFromPath}),
            enum2List(acl.getResources(TEST_RESOURCE)));
    }
    
    private static List enum2List(Enumeration e) {
        // JDK 1.4: return Collections.list(e);
        List l = new ArrayList();
        while (e.hasMoreElements()) {
            l.add(e.nextElement());
        }
        return l;
    }
    
    /** Special loader that just knows how to find TEST_RESOURCE. */
    private static final class ParentLoader extends ClassLoader {
        
        public ParentLoader() {}
        
        protected Enumeration findResources(String name) throws IOException {
            if (name.equals(TEST_RESOURCE)) {
                return Collections.enumeration(
                    Collections.singleton(
                        new URL("http://ant.apache.org/" + name)));
            } else {
                return Collections.enumeration(Collections.EMPTY_SET);
            }
        }
        
    }
    
}