/*
 * JBoss, Home of Professional Open Source.
 * Copyright 2008, Red Hat Middleware LLC, and individual contributors
 * as indicated by the @author tags. See the copyright.txt file in the
 * distribution for a full listing of individual contributors. 
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */
package org.jboss.web.tomcat.service.deployers;

import java.security.AccessController;
import java.security.PrivilegedAction;
import java.security.PrivilegedActionException;
import java.security.PrivilegedExceptionAction;

/**
 * Privileged Blocks
 * @author Anil.Saldhana@redhat.com
 * @since Nov 7, 2008
 */
class SecurityActions
{
   interface TCLAction
   {
      class UTIL
      {
         static TCLAction getTCLAction()
         {
            return System.getSecurityManager() == null ? NON_PRIVILEGED : PRIVILEGED;
         }

         static ClassLoader getContextClassLoader()
         {
            return getTCLAction().getContextClassLoader();
         }

         static ClassLoader getContextClassLoader(Thread thread)
         {
            return getTCLAction().getContextClassLoader(thread);
         }

         static void setContextClassLoader(ClassLoader cl)
         {
            getTCLAction().setContextClassLoader(cl);
         }

         static void setContextClassLoader(Thread thread, ClassLoader cl)
         {
            getTCLAction().setContextClassLoader(thread, cl);
         }
      }

      TCLAction NON_PRIVILEGED = new TCLAction()
      {
         public ClassLoader getContextClassLoader()
         {
            return Thread.currentThread().getContextClassLoader();
         }

         public ClassLoader getContextClassLoader(Thread thread)
         {
            return thread.getContextClassLoader();
         }

         public void setContextClassLoader(ClassLoader cl)
         {
            Thread.currentThread().setContextClassLoader(cl);
         }

         public void setContextClassLoader(Thread thread, ClassLoader cl)
         {
            thread.setContextClassLoader(cl);
         }
      };

      TCLAction PRIVILEGED = new TCLAction()
      {
         private final PrivilegedAction getTCLPrivilegedAction = new PrivilegedAction()
         {
            public Object run()
            {
               return Thread.currentThread().getContextClassLoader();
            }
         };

         public ClassLoader getContextClassLoader()
         {
            return (ClassLoader)AccessController.doPrivileged(getTCLPrivilegedAction);
         }

         public ClassLoader getContextClassLoader(final Thread thread)
         {
            return (ClassLoader)AccessController.doPrivileged(new PrivilegedAction()
            {
               public Object run()
               {
                  return thread.getContextClassLoader();
               }
            });
         }

         public void setContextClassLoader(final ClassLoader cl)
         {
            AccessController.doPrivileged(
               new PrivilegedAction()
               {
                  public Object run()
                  {
                     Thread.currentThread().setContextClassLoader(cl);
                     return null;
                  }
               }
            );
         }

         public void setContextClassLoader(final Thread thread, final ClassLoader cl)
         {
            AccessController.doPrivileged(
               new PrivilegedAction()
               {
                  public Object run()
                  {
                     thread.setContextClassLoader(cl);
                     return null;
                  }
               }
            );
         }
      };

      ClassLoader getContextClassLoader();

      ClassLoader getContextClassLoader(Thread thread);

      void setContextClassLoader(ClassLoader cl);

      void setContextClassLoader(Thread thread, ClassLoader cl);
   }

   static String getSystemProperty(final String key, final String defaultValue)
   {
      return AccessController.doPrivileged(new PrivilegedAction<String>()
      {
         public String run()
         {
            return System.getProperty(key, defaultValue); 
         }
      });
   }
   
   static void setSystemProperty(final String key, final String value)
   {
      AccessController.doPrivileged(new PrivilegedAction<Object>()
      {
         public Object run()
         {
            System.setProperty(key, value);
            return null;
         }
      });
   }
   
   static Class<?> loadClass(final String fqn) throws PrivilegedActionException
   {
      return AccessController.doPrivileged(new PrivilegedExceptionAction<Class<?>>() 
      {
         public Class<?> run() throws Exception
         {
            return Thread.currentThread().getContextClassLoader().loadClass(fqn);
         }
      } );  
   }

   static ClassLoader getContextClassLoader()
   {
      return TCLAction.UTIL.getContextClassLoader();
   }

   static void setContextClassLoader(ClassLoader loader)
   {
      TCLAction.UTIL.setContextClassLoader(loader);
   }
}