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/*
 * Copyright 2011 Lincoln Baxter, III
 *
 * 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.
 */
package org.ocpsoft.rewrite.util;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.LinkedHashMap;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;

/**
 * {@link Map} implementation supporting delegation to other {@link Map} instances configured with
 * {@link CompositeMap#addDelegate(Map)}.
 * 
 * @author Lincoln Baxter, III
 * 
 * @param 
 * @param 
 */
public class CompositeMap implements Map
{
   @SuppressWarnings("unchecked")
   private Map[] delegates = new Map[] {};

   @SuppressWarnings("unchecked")
   public CompositeMap addDelegate(Map delegate)
   {
      /*
       * Highly optimized for performance reasons. Think before you change this and profile after!
       */
      List> temp = new ArrayList>(Arrays.asList(delegates));
      temp.add(delegate);

      delegates = temp.toArray(new Map[] {});
      return this;
   }

   @Override
   public void clear()
   {
      for (Map delegate : delegates) {
         delegate.clear();
      }
   }

   @Override
   public boolean containsKey(Object key)
   {
      for (Map delegate : delegates) {
         if (delegate.containsKey(key))
            return true;
      }
      return false;
   }

   @Override
   public boolean containsValue(Object value)
   {
      for (Map delegate : delegates) {
         if (delegate.containsValue(value))
            return true;
      }
      return false;
   }

   @Override
   public Set> entrySet()
   {
      Set> entries = new LinkedHashSet>();
      for (Map delegate : delegates) {
         entries.addAll(delegate.entrySet());
      }
      return entries;
   }

   @Override
   public VALUETYPE get(Object key)
   {
      VALUETYPE result = null;
      for (Map delegate : delegates) {
         VALUETYPE v = delegate.get(key);
         if (v != null)
         {
            result = v;
            break;
         }
      }
      return result;
   }

   @Override
   public Object clone()
   {
      LinkedHashMap result = new LinkedHashMap();
      result.putAll(this);
      for (Map delegate : delegates) {
         result.putAll(delegate);
      }
      return result;
   }

   @Override
   public boolean isEmpty()
   {
      boolean empty = true;
      for (Map delegate : delegates) {
         if (!delegate.isEmpty())
         {
            empty = false;
            break;
         }
      }
      return empty;
   }

   @Override
   public Set keySet()
   {
      Set result = new LinkedHashSet();
      for (Map delegate : delegates) {
         result.addAll(delegate.keySet());
      }
      return result;
   }

   @Override
   public VALUETYPE put(KEYTYPE key, VALUETYPE value)
   {
      throw new UnsupportedOperationException("Cannot add values to composite map view.");
   }

   @Override
   public void putAll(Map map)
   {
      throw new UnsupportedOperationException("Cannot add values to composite map view.");
   }

   @Override
   public VALUETYPE remove(Object key)
   {
      throw new UnsupportedOperationException("Cannot remove values from composite map view.");
   }

   @Override
   public int size()
   {
      int size = 0;
      for (Map delegate : delegates) {
         size += delegate.size();
      }
      return size;
   }

   @Override
   public Collection values()
   {
      Set values = new LinkedHashSet();
      for (Map delegate : delegates) {
         values.addAll(delegate.values());
      }
      return values;
   }

}