- /*
- * $Header$
- * $Revision$
- * $Date$
- *
- * ====================================================================
- *
- * The Apache Software License, Version 1.1
- *
- * Copyright (c) 1999-2002 The Apache Software Foundation. All rights
- * reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- *
- * 1. Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *
- * 2. Redistributions in binary form must reproduce the above copyright
- * notice, this list of conditions and the following disclaimer in
- * the documentation and/or other materials provided with the
- * distribution.
- *
- * 3. The end-user documentation included with the redistribution, if
- * any, must include the following acknowlegement:
- * "This product includes software developed by the
- * Apache Software Foundation (http://www.apache.org/)."
- * Alternately, this acknowlegement may appear in the software itself,
- * if and wherever such third-party acknowlegements normally appear.
- *
- * 4. The names "The Jakarta Project", "Commons", and "Apache Software
- * Foundation" must not be used to endorse or promote products derived
- * from this software without prior written permission. For written
- * permission, please contact apache@apache.org.
- *
- * 5. Products derived from this software may not be called "Apache"
- * nor may "Apache" appear in their names without prior written
- * permission of the Apache Group.
- *
- * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
- * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
- * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
- * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
- * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
- * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
- * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
- * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
- * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
- * ====================================================================
- *
- * This software consists of voluntary contributions made by many
- * individuals on behalf of the Apache Software Foundation. For more
- * information on the Apache Software Foundation, please see
- * <http://www.apache.org/>.
- *
- */
-
- package org.apache.commons.discovery.jdk;
-
- import java.io.IOException;
- import java.net.URL;
- import java.util.Enumeration;
-
-
- /**
- * @author Richard A. Sitze
- */
- class JDK11Hooks extends JDKHooks {
- private static final ClassLoader systemClassLoader
- = new PsuedoSystemClassLoader();
-
-
- /**
- * The thread context class loader is available for JDK 1.2
- * or later, if certain security conditions are met.
- *
- * @return The thread context class loader, if available.
- * Otherwise return null.
- */
- public ClassLoader getThreadContextClassLoader() {
- return null;
- }
-
- /**
- * The system class loader is available for JDK 1.2
- * or later, if certain security conditions are met.
- *
- * @return The system class loader, if available.
- * Otherwise return null.
- */
- public ClassLoader getSystemClassLoader() {
- return systemClassLoader;
- }
-
- /**
- * Implement ClassLoader.getResources for JDK 1.1
- *
- * On JDK1.1 there is no getResources() method. We emulate this by
- * using introspection and doing the lookup ourself, using the list
- * of URLs, via getURLs().
- */
- public Enumeration getResources(ClassLoader loader,
- String resourceName)
- throws IOException
- {
- /**
- * The simple answer is/was:
- * return loader.getResources(resourceName);
- *
- * However, some classloaders overload the behavior of getResource
- * (loadClass, etc) such that the order of returned results changes
- * from normally expected behavior.
- *
- * Example: locate classes/resources from child ClassLoaders first,
- * parents last (in some J2EE environs).
- *
- * The resource returned by getResource() should be the same as the
- * first resource returned by getResources(). Unfortunately, this
- * is not, and cannot be: getResources() is 'final' in the current
- * JDK's (1.2, 1.3, 1.4).
- *
- * To address this, the implementation of this method will
- * return an Enumeration such that the first element is the
- * results of getResource, and all trailing elements are
- * from getResources. On each iteration, we check so see
- * if the resource (from getResources) matches the first resource,
- * and eliminate the redundent element.
- */
-
- final URL first = (URL)loader.getResource(resourceName);
- final Enumeration rest = loader.getResources(resourceName);
-
- return new Enumeration() {
- private boolean firstDone = (first == null);
- private URL next = getNext();
-
- public Object nextElement() {
- URL o = next;
- next = getNext();
- return o;
- }
-
- public boolean hasMoreElements() {
- return next != null;
- }
-
- private URL getNext() {
- URL n;
-
- if (!firstDone) {
- /**
- * First time through, use results of getReference()
- * if they were non-null.
- */
- firstDone = true;
- n = first;
- } else {
- /**
- * Subsequent times through,
- * use results of getReferences()
- * but take out anything that matches 'first'.
- *
- * Iterate through list until we find one that
- * doesn't match 'first'.
- */
- n = null;
- while (rest.hasMoreElements() && n == null) {
- n = (URL)rest.nextElement();
- if (first != null &&
- n != null &&
- n.equals(first))
- {
- n = null;
- }
- }
- }
-
- return n;
- }
- };
- }
- }