001/*
002 * Copyright (c) 2013, Oracle and/or its affiliates. All rights reserved.
003 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
004 *
005 * This code is free software; you can redistribute it and/or modify it
006 * under the terms of the GNU General Public License version 2 only, as
007 * published by the Free Software Foundation.
008 *
009 * This code is distributed in the hope that it will be useful, but WITHOUT
010 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
011 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
012 * version 2 for more details (a copy is included in the LICENSE file that
013 * accompanied this code).
014 *
015 * You should have received a copy of the GNU General Public License version
016 * 2 along with this work; if not, write to the Free Software Foundation,
017 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
018 *
019 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
020 * or visit www.oracle.com if you need additional information or have any
021 * questions.
022 */
023package com.oracle.graal.compiler.common.util;
024
025import java.util.*;
026
027/**
028 * Mimic a set implementation with an ArrayList. Beneficial for small sets (compared to
029 * {@link HashSet}).
030 */
031public class ArraySet<E> extends ArrayList<E> implements Set<E> {
032    private static final long serialVersionUID = 4476957522387436654L;
033
034    public ArraySet() {
035        super();
036    }
037
038    public ArraySet(int i) {
039        super(i);
040    }
041
042    public ArraySet(Collection<? extends E> c) {
043        super(c);
044    }
045
046    @Override
047    public boolean add(E e) {
048        // avoid duplicated entries
049        if (contains(e)) {
050            return false;
051        }
052        return super.add(e);
053    }
054}