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/*
* File: FibonacciIterator.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:
* "Portions Copyright [year] [name of copyright owner]"
*/
package com.oracle.tools.util;
import java.util.Iterator;
/**
* An {@link Iterator} over the
* Fibonacci sequence.
*
* 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 FibonacciIterator implements Iterator
{
/**
* The iteration (digit) of the Fibonacci sequence the
* {@link Iterator} is currently up to.
*/
private long m_iteration;
/**
* The last two generated Fibonacci numbers
*/
private long[] m_previousValues;
/**
* Constructs a {@link FibonacciIterator}.
*/
public FibonacciIterator()
{
m_iteration = 0;
m_previousValues = new long[2];
}
/**
* {@inheritDoc}
*/
@Override
public boolean hasNext()
{
return true;
}
/**
* {@inheritDoc}
*/
@Override
public Long next()
{
if (m_iteration == 0)
{
m_previousValues[0] = 0;
m_previousValues[1] = 0;
}
else if (m_iteration == 1)
{
m_previousValues[0] = 0;
m_previousValues[1] = 1;
}
long result = m_previousValues[0] + m_previousValues[1];
if (m_iteration > 1)
{
m_previousValues[0] = m_previousValues[1];
m_previousValues[1] = result;
}
m_iteration++;
return result;
}
/**
* {@inheritDoc}
*/
@Override
public void remove()
{
throw new UnsupportedOperationException("Can't remove from a " + this.getClass().getName());
}
}