DenseIntMapImpl.java revision 673:6b017d166ac2 
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
26package com.sun.corba.se.impl.orbutil ;
27
28import 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 */
35public 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}
81