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+/*
+ * Copyright (c) 2003 - 2007 Israfil Consulting Services Corporation
+ * Copyright (c) 2003 - 2007 Christian Edward Gruber
+ * All Rights Reserved
+ *
+ * This software is licensed under the Berkeley Standard Distribution license,
+ * (BSD license), as defined below:
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ * list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ * this list of conditions and the following disclaimer in the documentation
+ * and/or other materials provided with the distribution.
+ * 3. Neither the name of Israfil Consulting Services nor the names of its contributors
+ * may be used to endorse or promote products derived from this software without
+ * specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
+ * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,
+ * OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * $Id: ArraySet.java 76 2006-08-03 15:37:05Z cgruber $
+ */
+package net.israfil.foundation.collections;
+
+import java.util.AbstractSet;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Iterator;
+
+/**
+ * An ArrayList backed Set implementation, whose primary purpose is
+ * to provide a Set that maintains the order of elements based on
+ * indexes and/or the order in which items are added. Most
+ * particularly it's to guarrantee deterministic results of an
+ * iterator, where the iterator provides each element in the order
+ * of the underlying list.
+ *
+ * Unlike a LinkedHashSet, this implementation leaves a duplicate
+ * element in its original position. It's performance characteristics
+ * on input are similar, since a comparison still has to happen
+ * for de-dupliation, but obtaining the item by index is constant time.
+ *
+ * TODO: Consider making this a SortedSet, using the list order as the guarrantee. Not sure if it's a legit use of the API.
+ * @See java.util.LinkedHashSet
+ * @author <a href="mailto:cgruber@israfil.net">Christian Edward Gruber </a>
+ */
+public class ArraySet<E> extends AbstractSet<E> {
+
+ private transient ArrayList<E> internalList;
+
+ public ArraySet() {
+ internalList = new ArrayList<E>();
+ }
+
+ public ArraySet(int initialCapacity) {
+ internalList = new ArrayList<E>(initialCapacity);
+ }
+
+ public ArraySet(Collection<E> col) {
+ internalList = new ArrayList<E>(col);
+ Iterator<E> i = col.iterator();
+ while (i.hasNext()) {
+ internalList.add(i.next());
+ }
+ }
+
+ @Override
+ public Iterator<E> iterator() {
+ return internalList.iterator();
+ }
+
+ @Override
+ public int size() {
+ return internalList.size();
+ }
+
+ @Override
+ public boolean add(E o) {
+ if (internalList.contains(o)) return false;
+ else {
+ internalList.add(o);
+ return true;
+ }
+ }
+
+ @Override
+ public boolean remove(Object o) {
+ return internalList.remove(o);
+ }
+
+ public E get(Integer index) {
+ return internalList.get(index);
+ }
+}