Author: werner
Date: Sat Dec 10 00:31:29 2005
New Revision: 355717
URL: http://svn.apache.org/viewcvs?rev=355717&view=rev
Log:
Chckin the Loader.
Added:
webservices/commons/trunk/policy/src/org/apache/ws/policy/util/Loader.java
Added:
webservices/commons/trunk/policy/src/org/apache/ws/policy/util/Loader.java
URL:
http://svn.apache.org/viewcvs/webservices/commons/trunk/policy/src/org/apache/ws/policy/util/Loader.java?rev=355717&view=auto
==============================================================================
--- webservices/commons/trunk/policy/src/org/apache/ws/policy/util/Loader.java
(added)
+++ webservices/commons/trunk/policy/src/org/apache/ws/policy/util/Loader.java
Sat Dec 10 00:31:29 2005
@@ -0,0 +1,164 @@
+/*
+ * Copyright 2003-2004 The Apache Software Foundation.
+ *
+ * Licensed 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.ws.policy.util;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+
+import java.lang.reflect.InvocationTargetException;
+import java.net.URL;
+
+/**
+ * Load resources (or images) from various sources.
+ * <p/>
+ *
+ * @author Davanum Srinivas ([EMAIL PROTECTED]).
+ */
+public class Loader {
+ private static Log log = LogFactory.getLog(Loader.class.getName());
+
+ /**
+ * This method will search for <code>resource</code> in different
+ * places. The rearch order is as follows:
+ * <ol>
+ * <p><li>Search for <code>resource</code> using the thread context
+ * class loader under Java2. If that fails, search for
+ * <code>resource</code> using the class loader that loaded this
+ * class (<code>Loader</code>).
+ * <p><li>Try one last time with
+ * <code>ClassLoader.getSystemResource(resource)</code>, that is is
+ * using the system class loader in JDK 1.2 and virtual machine's
+ * built-in class loader in JDK 1.1.
+ * </ol>
+ * <p/>
+ *
+ * @param resource
+ * @return TODO
+ */
+ static public URL getResource(String resource) {
+ ClassLoader classLoader = null;
+ URL url = null;
+ try {
+ // We could not find resource. Ler us now try with the
+ // classloader that loaded this class.
+ classLoader = getTCL();
+ if (classLoader != null) {
+ log.debug("Trying to find [" + resource + "] using " +
classLoader + " class loader.");
+ url = classLoader.getResource(resource);
+ if (url != null) {
+ return url;
+ }
+ }
+ } catch (Throwable t) {
+ log.warn("Caught Exception while in Loader.getResource. This may
be innocuous.", t);
+ }
+
+ // Last ditch attempt: get the resource from the class path. It
+ // may be the case that clazz was loaded by the Extentsion class
+ // loader which the parent of the system class loader. Hence the
+ // code below.
+ log.debug("Trying to find [" + resource + "] using
ClassLoader.getSystemResource().");
+ return ClassLoader.getSystemResource(resource);
+ }
+
+
+ /**
+ * Try to get the resource with the specified class loader
+ * <p/>
+ *
+ * @param cl
+ * @param clazz
+ * @return Class
+ * @throws ClassNotFoundException
+ */
+ static public URL getResource(ClassLoader loader, String resource) throws
ClassNotFoundException {
+ URL url = null;
+ try {
+ if (loader != null) {
+ log.debug("Trying to find [" + resource + "] using " + loader
+ " class loader.");
+ url = loader.getResource(resource);
+ if (url != null) {
+ return url;
+ }
+ }
+ } catch (Throwable t) {
+ log.warn("Caught Exception while in Loader.getResource. This may
be innocuous.", t);
+ }
+ return getResource(resource);
+ }
+
+ /**
+ * Get the Thread context class loader.
+ * <p/>
+ *
+ * @return
+ * @throws IllegalAccessException
+ * @throws InvocationTargetException
+ */
+ static public ClassLoader getTCL() throws IllegalAccessException,
InvocationTargetException {
+ return Thread.currentThread().getContextClassLoader();
+ }
+
+ /**
+ * Try the specified classloader and then fall back to the loadClass
+ * <p/>
+ *
+ * @param cl
+ * @param clazz
+ * @return Class
+ * @throws ClassNotFoundException
+ */
+ static public Class loadClass(ClassLoader loader, String clazz) throws
ClassNotFoundException {
+ try {
+ if(loader != null) {
+ Class c = loader.loadClass(clazz);
+ if (c != null)
+ return c;
+ }
+ } catch (Throwable e) {
+ }
+ return loadClass(clazz);
+ }
+
+ /**
+ * If running under JDK 1.2 load the specified class using the
+ * <code>Thread</code> <code>contextClassLoader</code> if that
+ * fails try Class.forname.
+ * <p/>
+ *
+ * @param clazz
+ * @return TODO
+ * @throws ClassNotFoundException
+ */
+ static public Class loadClass(String clazz) throws ClassNotFoundException {
+ try {
+ ClassLoader tcl = getTCL();
+
+ if(tcl != null) {
+ Class c = tcl.loadClass(clazz);
+ if (c != null)
+ return c;
+ }
+ } catch (Throwable e) {
+ }
+ // we reached here because tcl was null or because of a
+ // security exception, or because clazz could not be loaded...
+ // In any case we now try one more time
+ return Class.forName(clazz);
+ }
+}
