/* 
    P/P   *  Method: com.dmdirc.util.WeakMapList__static_init
          */
     1  /*
     2   * Copyright (c) 2006-2009 Chris Smith, Shane Mc Cormack, Gregory Holmes
     3   *
     4   * Permission is hereby granted, free of charge, to any person obtaining a copy
     5   * of this software and associated documentation files (the "Software"), to deal
     6   * in the Software without restriction, including without limitation the rights
     7   * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
     8   * copies of the Software, and to permit persons to whom the Software is
     9   * furnished to do so, subject to the following conditions:
    10   *
    11   * The above copyright notice and this permission notice shall be included in
    12   * all copies or substantial portions of the Software.
    13   *
    14   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    15   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    16   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    17   * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    18   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
    19   * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
    20   * SOFTWARE.
    21   */
    22  
    23  package com.dmdirc.util;
    24  
    25  import java.util.List;
    26  
    27  /**
    28   * Wraps a Map<S, List<T>> with various convenience methods for
    29   * accessing the data. Implements a Map-like interface for easier transition.
    30   * This implementation uses WeakLists (i.e., lists of weak references) - all
    31   * references to values are wrapped in WeakReferences.
    32   * 
    33   * @param <S> the type of keys maintained by this map
    34   * @param <T> the type of mapped values
    35   * @author chris
    36   */
         /* 
    P/P   *  Method: void com.dmdirc.util.WeakMapList()
          * 
          *  Postconditions:
          *    this.map == &amp;new HashMap(MapList#1)
          *    new HashMap(MapList#1) num objects == 1
          */
    37  public class WeakMapList<S,T> extends MapList<S,T> {
    38      
    39      /**
    40       * Retrieves the list of values associated with the specified key, creating
    41       * the key if neccessary.
    42       * 
    43       * @param key The key to retrieve
    44       * @return A list of the specified key's values
    45       */
    46      @Override
    47      public List<T> safeGet(final S key) {
                 /* 
    P/P           *  Method: List safeGet(Object)
                  * 
                  *  Preconditions:
                  *    this.map != null
                  * 
                  *  Postconditions:
                  *    init'ed(return_value)
                  * 
                  *  Test Vectors:
                  *    java.util.Map:containsKey(...)@48: {1}, {0}
                  */
    48          if (!map.containsKey(key)) {
    49              map.put(key, new WeakList<T>());
    50          }
    51          
    52          return map.get(key);
    53      }
    54  }