ChainedMap.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.util.HashMap;
import java.util.Map;

/**
 * Represents a PHP chained map
 */
public class ChainedMap<K, V> implements VarMap<K, V> {

   private final VarMap<K, V> _next;
   private final Map<K, V> _map;

   public ChainedMap(VarMap<K, V> next, Map<K, V> map) {
      _next = next;
      _map = map;
   }

   public ChainedMap(VarMap<K, V> next) {
      _next = next;
      _map = new HashMap<K, V>();
   }

   /**
    * Sets the value
    */
   @Override
   public void put(K key, V value) {
      _map.put(key, value);
   }

   /**
    * Remove the value
    */
   @Override
   public V remove(K key) {
      return _map.remove(key);
   }

   /**
    * Gets a value.
    */
   @Override
   public V get(K key) {
      V value = _map.get(key);

      if (value != null) {
         return value;
      } else if (_next != null) {
         return _next.get(key);
      } else {
         return null;
      }
   }
}