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/*
* File: RandomIterator.java
*
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
*
* The contents of this file are subject to the terms and conditions of
* the Common Development and Distribution License 1.0 (the "License").
*
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the License by consulting the LICENSE.txt file
* distributed with this file, or by consulting https://oss.oracle.com/licenses/CDDL
*
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing the software, include this License Header Notice in each
* file and include the License file LICENSE.txt.
*
* MODIFICATIONS:
* If applicable, add the following below the License Header, with the fields
* enclosed by brackets [] replaced by your own identifying information:
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*/
package com.oracle.tools.util;
import java.util.Iterator;
import java.util.Random;
/**
* An {@link Iterator} over a positive sequence of random {@link Long} numbers.
*
* Copyright (c) 2013. All Rights Reserved. Oracle Corporation.
* Oracle is a registered trademark of Oracle Corporation and/or its affiliates.
*
* @author Brian Oliver
*/
public class RandomIterator implements Iterator
{
/**
* The range for the next random number to generate.
*/
private Iterator m_ranges;
/**
* The {@link Random} number generator.
*/
private Random m_random;
/**
* Constructs a {@link RandomIterator} that uses the
* ranges provided by the range {@link Iterator} for
* each random number generated.
*
* Ranges are from 0 to the numbers provided by the
* specified {@link Iterator} (exclusive).
*
* @param ranges an {@link Iterator} providing ranges.
*/
public RandomIterator(Iterator ranges)
{
m_ranges = ranges;
m_random = new Random(System.nanoTime());
}
/**
* Constructs a {@link RandomIterator} for numbers between
* 0 and the specified range (exclusive).
*
* @param range the upper bound of the range
*/
public RandomIterator(long range)
{
this(new ConstantIterator(range));
}
/**
* {@inheritDoc}
*/
@Override
public boolean hasNext()
{
return m_ranges.hasNext();
}
/**
* {@inheritDoc}
*/
@Override
public Long next()
{
long range = m_ranges.next();
long random = Math.abs(m_random.nextLong());
return range == 0 ? 0 : random % range;
}
/**
* {@inheritDoc}
*/
@Override
public void remove()
{
throw new UnsupportedOperationException("Can't remove from a " + this.getClass().getName());
}
}