/*

  * 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.

  */

 package org.apache.myfaces.shared.util;

 import java.util.HashMap;

 import java.util.Map;

 import java.util.Set;

 import java.util.Iterator;

 public class HashMapUtils

 {

     //~ Constructors -------------------------------------------------------------------------------

     protected HashMapUtils()

     {

         // block public access

     }

     //~ Methods ------------------------------------------------------------------------------------

     /**

      * Calculates initial capacity needed to hold <code>size</code> elements in

      * a HashMap or Hashtable without forcing an expensive increase in internal

      * capacity. Capacity is based on the default load factor of .75.

      * <p>

      * Usage: <code>Map map = new HashMap(HashMapUtils.calcCapacity(10));<code>

      * </p>

      * @param size the number of items that will be put into a HashMap

      * @return initial capacity needed

      */

     public static final int calcCapacity(int size)

     {

         return ((size * 4) + 3) / 3;

     }

     /**

      * Creates a new <code>HashMap</code> that has all of the elements

      * of <code>map1</code> and <code>map2</code> (on key collision, the latter

      * override the former).

      *

      * @param map1 the fist hashmap to merge

      * @param map2 the second hashmap to merge

      * @return new hashmap

      */

     public static HashMap merge(Map map1, Map map2)

     {

         HashMap retval = new HashMap(calcCapacity(map1.size() + map2.size()));

         retval.putAll(map1);

         retval.putAll(map2);

         return retval;

     }

      /**

      * spit out each name/value pair

      */

     public static String mapToString(Map map)

     {

         Set entries = map.entrySet();

         Iterator iter = entries.iterator();

         StringBuffer buff = new StringBuffer();

         while (iter.hasNext())

         {

             Map.Entry entry = (Map.Entry) iter.next();

             buff.append("[" + entry.getKey() + "," + entry.getValue() + "]\n");

         }

         return buff.toString();

     }

 }