1 /*
   2  * Copyright (c) 2013, 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.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  */
  23 package org.graalvm.compiler.core.common.util;
  24 
  25 import java.util.ArrayList;
  26 import java.util.Collection;
  27 import java.util.HashSet;
  28 import java.util.Set;
  29 
  30 /**
  31  * Mimic a set implementation with an ArrayList. Beneficial for small sets (compared to
  32  * {@link HashSet}).
  33  */
  34 public class ArraySet<E> extends ArrayList<E> implements Set<E> {
  35     private static final long serialVersionUID = 4476957522387436654L;
  36 
  37     public ArraySet() {
  38         super();
  39     }
  40 
  41     public ArraySet(int i) {
  42         super(i);
  43     }
  44 
  45     public ArraySet(Collection<? extends E> c) {
  46         super(c);
  47     }
  48 
  49     @Override
  50     public boolean add(E e) {
  51         // avoid duplicated entries
  52         if (contains(e)) {
  53             return false;
  54         }
  55         return super.add(e);
  56     }
  57 }