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.
   */
  /*
   * $Id$
   */
  
  package org.apache.xpath.functions;
  
  import java.io.File;
  import java.io.FileInputStream;
  import java.io.FileNotFoundException;
  import java.io.InputStream;
  import java.security.AccessController;
  import java.security.PrivilegedAction;
  import java.security.PrivilegedActionException;
  import java.security.PrivilegedExceptionAction;
  
  /**
   * This class is duplicated for each Xalan-Java subpackage so keep it in sync.
   * It is package private and therefore is not exposed as part of the Xalan-Java
   * API.
   *
   * Security related methods that only work on J2SE 1.2 and newer.
   */
  final class SecuritySupport {
  
      static ClassLoader getContextClassLoader() {
          return (ClassLoader)
                  AccessController.doPrivileged(new PrivilegedAction() {
              public Object run() {
                  ClassLoader cl = null;
                  try {
                      cl = Thread.currentThread().getContextClassLoader();
                  } catch (SecurityException ex) { }
                  return cl;
              }
          });
      }
  
      static ClassLoader getSystemClassLoader() {
          return (ClassLoader)
              AccessController.doPrivileged(new PrivilegedAction() {
                  public Object run() {
                      ClassLoader cl = null;
                      try {
                          cl = ClassLoader.getSystemClassLoader();
                      } catch (SecurityException ex) {}
                      return cl;
                  }
              });
      }
  
      static ClassLoader getParentClassLoader(final ClassLoader cl) {
          return (ClassLoader)
              AccessController.doPrivileged(new PrivilegedAction() {
                  public Object run() {
                      ClassLoader parent = null;
                      try {
                          parent = cl.getParent();
                      } catch (SecurityException ex) {}
  
                      // eliminate loops in case of the boot
                      // ClassLoader returning itself as a parent
                      return (parent == cl) ? null : parent;
                  }
              });
      }
  
      static String getSystemProperty(final String propName) {
          return (String)
              AccessController.doPrivileged(new PrivilegedAction() {
                  public Object run() {
                      return System.getProperty(propName);
                  }
              });
      }
  
      static FileInputStream getFileInputStream(final File file)
          throws FileNotFoundException
      {
          try {
              return (FileInputStream)
                  AccessController.doPrivileged(new PrivilegedExceptionAction() {
                      public Object run() throws FileNotFoundException {
                          return new FileInputStream(file);
                      }
                  });
          } catch (PrivilegedActionException e) {
              throw (FileNotFoundException)e.getException();
          }
      }
  
      static InputStream getResourceAsStream(final ClassLoader cl,
                                             final String name)
      {
          return (InputStream)
              AccessController.doPrivileged(new PrivilegedAction() {
                  public Object run() {
                      InputStream ris;
                      if (cl == null) {
                          ris = ClassLoader.getSystemResourceAsStream(name);
                      } else {
                          ris = cl.getResourceAsStream(name);
                      }
                      return ris;
                  }
              });
      }
      
      static boolean getFileExists(final File f) {
      return ((Boolean)
              AccessController.doPrivileged(new PrivilegedAction() {
                  public Object run() {
                      return f.exists() ? Boolean.TRUE : Boolean.FALSE;
                  }
              })).booleanValue();
      }
      
      static long getLastModified(final File f) {
      return ((Long)
              AccessController.doPrivileged(new PrivilegedAction() {
                  public Object run() {
                      return new Long(f.lastModified());
                  }
              })).longValue();
      }
      
      private SecuritySupport () {}
  }
  