From 7c279747beb43c7e88633a6228a155a30e6834f7 Mon Sep 17 00:00:00 2001
From: Benjamin Culkin <scorpress@gmail.com>
Date: Mon, 27 May 2024 11:38:33 -0400
Subject: Initial import

---
 .../collections/RandomOrderIterator.java           | 94 ++++++++++++++++++++++
 1 file changed, 94 insertions(+)
 create mode 100644 israfil-foundation-collections/src/main/java/net/israfil/foundation/collections/RandomOrderIterator.java

(limited to 'israfil-foundation-collections/src/main/java/net/israfil/foundation/collections/RandomOrderIterator.java')

diff --git a/israfil-foundation-collections/src/main/java/net/israfil/foundation/collections/RandomOrderIterator.java b/israfil-foundation-collections/src/main/java/net/israfil/foundation/collections/RandomOrderIterator.java
new file mode 100644
index 0000000..8b97e4a
--- /dev/null
+++ b/israfil-foundation-collections/src/main/java/net/israfil/foundation/collections/RandomOrderIterator.java
@@ -0,0 +1,94 @@
+/*
+ * Copyright (c) 2007 Israfil Consulting Services Corporation
+ * Copyright (c) 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.security.SecureRandom;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Iterator;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Random;
+
+/**
+ * An iterator that is constructed from a collection and returns the 
+ * contents of the collection in random order.  Note that this is 
+ * an iterator over a copy of the collection, not the collection 
+ * itself, so remove() is not supported, and underlying changes
+ * to the original collection will not be reflected in this iterator.
+ * 
+ * @author <a href="mailto:cgruber@israfil.net">Christian Edward Gruber </a>
+ */
+public class RandomOrderIterator<E> implements Iterator<E>  {
+
+	private transient List<E> _collection;
+	
+	private transient Random _random = new SecureRandom();
+	
+	private transient List<Integer> _indexes;
+	
+	
+	public RandomOrderIterator(Collection<E> collection) {
+		_collection = new ArrayList<E>(collection);
+		_indexes = new LinkedList<Integer>();
+		for (int i = 0; i < _collection.size();i++) {
+			_indexes.add(i); // populate index source.
+		}
+	}
+
+	public RandomOrderIterator(Collection<E> collection, Random random) {
+		this(collection);
+		this._random = random;
+	}
+
+	public boolean hasNext() {
+		return _indexes.size() > 0;
+	}
+
+	public E next() {
+		Integer index = _indexes.remove(_random.nextInt(_indexes.size()));
+		return _collection.get(index);
+	}
+
+	/**
+	 * Because of the means required to track the current node,
+	 * removing anything from the underlying collection is not supported.
+	 */
+	public void remove() {
+		throw new UnsupportedOperationException();
+	}
+	
+	
+		
+}
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