UnserializeCacheEntry.java

/*
 * Copyright (c) 1998-2010 Caucho Technology -- all rights reserved
 *
 * This file is part of Resin(R) Open Source
 *
 * Each copy or derived work must preserve the copyright notice and this
 * notice unmodified.
 *
 * Resin Open Source is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * Resin Open Source 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, or any warranty
 * of NON-INFRINGEMENT.  See the GNU General Public License for more
 * details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Resin Open Source; if not, write to the
 *
 *   Free Software Foundation, Inc.
 *   59 Temple Place, Suite 330
 *   Boston, MA 02111-1307  USA
 *
 * @author Scott Ferguson
 */
package com.caucho.quercus.env;

import java.lang.ref.*;
import com.caucho.util.*;

/**
 * Cache entry root
 */
public class UnserializeCacheEntry {

   private FreeList<SoftReference<CopyRoot>> _freeList;
   private SoftReference<Value> _valueRef;

   public UnserializeCacheEntry(Value value) {
      _valueRef = new SoftReference<Value>(value);
   }

   public UnserializeCacheEntry(Env env, Value value) {
      CopyRoot root = new CopyRoot(this);

      value = value.copyTree(env, root);

      _valueRef = new SoftReference<Value>(value);
   }

   public Value getValue(Env env) {
      SoftReference<CopyRoot> copyRef = null;

      if (_freeList != null) {
         copyRef = _freeList.allocate();
      }

      if (copyRef != null) {
         CopyRoot copy = copyRef.get();

         if (copy != null) {
            copy.allocate(env);

            return copy.getRoot();
         }
      }

      Value value = null;

      if (_valueRef != null) {
         value = _valueRef.get();
      }

      if (value != null) {
         CopyRoot root = new CopyRoot(this);

         root.allocate(env);

         Value copy = value.copyTree(env, root);

         root.setRoot(copy);

         return copy;
      } else {
         return null;
      }
   }

   public void clear() {
      _valueRef = null;
      _freeList = null;
   }

   void free(CopyRoot root) {
      if (_freeList == null) {
         _freeList = new FreeList<SoftReference<CopyRoot>>(2);
      }

      _freeList.free(new SoftReference<CopyRoot>(root));
   }
}