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    1   /*
    2    * Licensed to the Apache Software Foundation (ASF) under one
    3    * or more contributor license agreements.  See the NOTICE file
    4    * distributed with this work for additional information
    5    * regarding copyright ownership.  The ASF licenses this file
    6    * to you under the Apache License, Version 2.0 (the
    7    * "License"); you may not use this file except in compliance
    8    * with the License.  You may obtain a copy of the License at
    9    *
    10   *   http://www.apache.org/licenses/LICENSE-2.0
    11   *
    12   * Unless required by applicable law or agreed to in writing,
    13   * software distributed under the License is distributed on an
    14   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
    15   * KIND, either express or implied.  See the License for the
    16   * specific language governing permissions and limitations
    17   * under the License.
    18   */
    19  package org.apache.myfaces.shared_orchestra.util;
    20
    21  import java.util.HashMap;
    22  import java.util.Map;
    23  import java.util.Set;
    24  import java.util.Iterator;
    25
    26
    27  /**
    28   * @author Anton Koinov (latest modification by $Author: grantsmith $)
    29   * @version $Revision: 472630 $ $Date: 2006-11-08 15:40:03 -0500 (Wed, 08 Nov 2006) $
    30   */
    31  public class HashMapUtils
    32  {
    33      //~ Constructors -------------------------------------------------------------------------------
    34
    35      protected HashMapUtils()
    36      {
    37          // block public access
    38      }
    39
    40      //~ Methods ------------------------------------------------------------------------------------
    41
    42      /**
    43       * Calculates initial capacity needed to hold <code>size</code> elements in
    44       * a HashMap or Hashtable without forcing an expensive increase in internal
    45       * capacity. Capacity is based on the default load factor of .75.
    46       * <p>
    47       * Usage: <code>Map map = new HashMap(HashMapUtils.calcCapacity(10));<code>
    48       * </p>
    49       * @param size the number of items that will be put into a HashMap
    50       * @return initial capacity needed
    51       */
    52      public static final int calcCapacity(int size)
    53      {
    54          return ((size * 4) + 3) / 3;
    55      }
    56
    57      /**
    58       * Creates a new <code>HashMap</code> that has all of the elements
    59       * of <code>map1</code> and <code>map2</code> (on key collision, the latter
    60       * override the former).
    61       *
    62       * @param map1 the fist hashmap to merge
    63       * @param map2 the second hashmap to merge
    64       * @return new hashmap
    65       */
    66      public static HashMap merge(Map map1, Map map2)
    67      {
    68          HashMap retval = new HashMap(calcCapacity(map1.size() + map2.size()));
    69
    70          retval.putAll(map1);
    71          retval.putAll(map2);
    72
    73          return retval;
    74      }
    75
    76       /**
    77       * spit out each name/value pair
    78       */
    79      public static String mapToString(Map map){
    80          Set entries = map.entrySet();
    81          Iterator iter = entries.iterator();
    82          StringBuffer buff = new StringBuffer();
    83          while (iter.hasNext())
    84          {
    85              Map.Entry entry = (Map.Entry) iter.next();
    86              buff.append("[" + entry.getKey() + "," + entry.getValue() + "]\n");
    87          }
    88          return buff.toString();
    89      }
    90
    91  }