1 /*
   2  * Copyright (c) 2003, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package com.sun.corba.se.impl.orbutil ;
  27 
  28 import java.util.ArrayList ;
  29 
  30 /** Utility for managing mappings from densely allocated integer
  31  * keys to arbitrary objects.  This should only be used for
  32  * keys in the range 0..max such that "most" of the key space is actually
  33  * used.
  34  */
  35 public class DenseIntMapImpl
  36 {
  37     private ArrayList list = new ArrayList() ;
  38 
  39     private void checkKey( int key )
  40     {
  41         if (key < 0)
  42             throw new IllegalArgumentException( "Key must be >= 0." ) ;
  43     }
  44 
  45     /**
  46      * If {@code key >= 0}, return the value bound to key, or null if none.
  47      * Throws IllegalArgumentException if {@code key < 0}.
  48      */
  49     public Object get( int key )
  50     {
  51         checkKey( key ) ;
  52 
  53         Object result = null ;
  54         if (key < list.size())
  55             result = list.get( key ) ;
  56 
  57         return result ;
  58     }
  59 
  60     /**
  61      * If {@code key >= 0}, bind value to the key.
  62      * Throws IllegalArgumentException if {@code key < 0}.
  63      */
  64     public void set( int key, Object value )
  65     {
  66         checkKey( key ) ;
  67         extend( key ) ;
  68         list.set( key, value ) ;
  69     }
  70 
  71     private void extend( int index )
  72     {
  73         if (index >= list.size()) {
  74             list.ensureCapacity( index + 1 ) ;
  75             int max = list.size() ;
  76             while (max++ <= index)
  77                 list.add( null ) ;
  78         }
  79     }
  80 }