Search for resource in different places. : AccessController « Security « Java






Search for resource in different places.

 
/*
 * Copyright  2003-2008 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.
 *
 */
import java.lang.reflect.InvocationTargetException;
import java.net.URL;
import java.security.AccessController;
import java.security.PrivilegedAction;

public class Main {

  /**
   * This method will search for <code>resource</code> in different
   * places. The search order is as follows:
   * <ol>
   * <p><li>Search for <code>resource</code> using the thread context
   * class loader under Java2.
   * <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
   */
  public static URL getResource(String resource) {
      ClassLoader classLoader = null;
      URL url = null;
      try {
          classLoader = getTCL();
          if (classLoader != null) {
              url = classLoader.getResource(resource);
              if (url != null) {
                  return url;
              }
          }
      } catch (Throwable t) {

      }
  
      // 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.
   
      return ClassLoader.getSystemResource(resource);
  }
  /**
   * Get the Thread context class loader.
   * <p/>
   *
   * @return the Thread context class loader
   * @throws IllegalAccessException
   * @throws InvocationTargetException
   */
  public static ClassLoader getTCL() throws IllegalAccessException, InvocationTargetException {
       return (ClassLoader)AccessController.doPrivileged(new PrivilegedAction() {
          public Object run() {
              return Thread.currentThread().getContextClassLoader();
          }
       });
  }
}

   
  








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