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The Apache WSS4J project provides a Java implementation of the primary security standards
for Web Services, namely the OASIS Web Services Security (WS-Security) specifications
from the OASIS Web Services Security TC.
/**
* 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.ws.security.util;
import java.lang.reflect.InvocationTargetException;
import java.net.URL;
import java.security.AccessController;
import java.security.PrivilegedAction;
/**
* Load resources (or images) from various sources.
*
*
* @author Davanum Srinivas ([email protected]).
*/
public final class Loader {
private static org.apache.commons.logging.Log log =
org.apache.commons.logging.LogFactory.getLog(Loader.class);
private Loader() {
// Complete
}
/**
* This method will search for resource in different
* places. The search order is as follows:
*
* - Search for
resource using the thread context
* class loader under Java2.
* - Try one last time with
*
ClassLoader.getSystemResource(resource), that is is
* using the system class loader in JDK 1.2 and virtual machine's
* built-in class loader in JDK 1.1.
*
*
*
* @param resource
* @return TODO
*/
public static URL getResource(String resource) {
URL url = null;
try {
ClassLoader classLoader = getTCL();
if (classLoader != null) {
log.debug("Trying to find [" + resource + "] using " + classLoader + " class loader.");
url = classLoader.getResource(resource);
if (url == null && resource.startsWith("/")) {
//certain classloaders need it without the leading /
url = classLoader.getResource(resource.substring(1));
}
if (url != null) {
return url;
}
}
} catch (Throwable t) {
log.warn("Caught Exception while in Loader.getResource. This may be innocuous.", t);
}
ClassLoader cluClassloader = Loader.class.getClassLoader();
if (cluClassloader == null) {
cluClassloader = ClassLoader.getSystemClassLoader();
}
url = cluClassloader.getResource(resource);
if (url == null && resource.startsWith("/")) {
//certain classloaders need it without the leading /
url = cluClassloader.getResource(resource.substring(1));
}
if (url != null) {
return url;
}
// Last ditch attempt: get the resource from the class path. It
// may be the case that clazz was loaded by the Extension 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);
}
/**
* This method will search for resource in different
* places. The search order is as follows:
*
* - Search for
resource using the supplied class loader.
* If that fails, search for resource using the thread context
* class loader.
* - Try one last time with
*
ClassLoader.getSystemResource(resource), that is is
* using the system class loader in JDK 1.2 and virtual machine's
* built-in class loader in JDK 1.1.
*
*
*
* @param resource
* @return TODO
*/
public static URL getResource(ClassLoader loader, String resource) {
URL url = null;
try {
if (loader != null) {
log.debug("Trying to find [" + resource + "] using " + loader + " class loader.");
url = loader.getResource(resource);
if (url == null && resource.startsWith("/")) {
//certain classloaders need it without the leading /
url = loader.getResource(resource.substring(1));
}
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.
*
*
* @return the Thread context class loader
* @throws IllegalAccessException
* @throws InvocationTargetException
*/
public static ClassLoader getTCL() throws IllegalAccessException, InvocationTargetException {
return AccessController.doPrivileged(new PrivilegedAction() {
public ClassLoader run() {
return Thread.currentThread().getContextClassLoader();
}
});
}
/**
* Get the class loader of the class argument
*
*
* @return the class loader of the argument
*/
public static ClassLoader getClassLoader(final Class clazz) {
return AccessController.doPrivileged(new PrivilegedAction() {
public ClassLoader run() {
return clazz.getClassLoader();
}
});
}
/**
* Try the specified classloader and then fall back to the loadClass
*
*
* @param loader
* @param clazz
* @return Class
* @throws ClassNotFoundException
*/
public static 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) {
log.warn(e.getMessage(), e);
}
return loadClass(clazz, true);
}
/**
* Try the specified classloader and then fall back to the loadClass
*
*
* @param loader
* @param clazz
* @param type
* @return Class
* @throws ClassNotFoundException
*/
public static Class loadClass(ClassLoader loader,
String clazz,
Class type) throws ClassNotFoundException {
try {
if (loader != null) {
Class c = loader.loadClass(clazz);
if (c != null) {
return c.asSubclass(type);
}
}
} catch (Throwable e) {
log.warn(e.getMessage(), e);
}
return loadClass(clazz, true, type);
}
/**
* If running under JDK 1.2 load the specified class using the
* Thread contextClassLoader if that
* fails try Class.forname.
*
*
* @param clazz
* @return TODO
* @throws ClassNotFoundException
*/
public static Class loadClass(String clazz) throws ClassNotFoundException {
return loadClass(clazz, true);
}
/**
* If running under JDK 1.2 load the specified class using the
* Thread contextClassLoader if that
* fails try Class.forname.
*
*
* @param clazz
* @param type Type to cast it to
* @return TODO
* @throws ClassNotFoundException
*/
public static Class loadClass(String clazz, Class type)
throws ClassNotFoundException {
return loadClass(clazz, true, type);
}
public static Class loadClass(String clazz,
boolean warn,
Class type) throws ClassNotFoundException {
return loadClass(clazz, warn).asSubclass(type);
}
public static Class loadClass(String clazz, boolean warn) throws ClassNotFoundException {
try {
ClassLoader tcl = getTCL();
if (tcl != null) {
Class c = tcl.loadClass(clazz);
if (c != null) {
return c;
}
}
} catch (Throwable e) {
if (warn) {
log.warn(e.getMessage(), e);
} else {
log.debug(e.getMessage(), e);
}
}
return loadClass2(clazz, null);
}
private static Class loadClass2(String className, Class callingClass)
throws ClassNotFoundException {
try {
return Class.forName(className);
} catch (ClassNotFoundException ex) {
try {
if (Loader.class.getClassLoader() != null) {
return Loader.class.getClassLoader().loadClass(className);
}
} catch (ClassNotFoundException exc) {
if (callingClass != null && callingClass.getClassLoader() != null) {
return callingClass.getClassLoader().loadClass(className);
}
}
throw ex;
}
}
}