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ParallelJ is a Java framework for parallel computing. It provides flow modeling and execution. This project contains the core of ParallelJ which brings the execution engine, but also all the elements you need to define a ParallelJ program: annotations, libraries, etc.

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/*
 *     ParallelJ, framework for parallel computing
 *
 *     Copyright (C) 2010, 2011, 2012 Atos Worldline or third-party contributors as
 *     indicated by the @author tags or express copyright attribution
 *     statements applied by the authors.
 *
 *     This library is free software; you can redistribute it and/or
 *     modify it under the terms of the GNU Lesser General Public
 *     License as published by the Free Software Foundation; either
 *     version 2.1 of the License.
 *
 *     This library is distributed in the hope that it will be useful,
 *     but WITHOUT ANY WARRANTY; without even the implied warranty of
 *     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 *     Lesser General Public License for more details.
 *
 *     You should have received a copy of the GNU Lesser General Public
 *     License along with this library; if not, write to the Free Software
 *     Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */
package org.parallelj.util;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.NoSuchElementException;

/**
 * 
 * 
 * @author Atos Worldline
 *
 * @param 
 */
public class BufferedIterable implements Iterable {
	
	public static final int DEFAULT_SIZE = 32;

	class IteratorImpl implements Iterator {

		Iterator iterator = BufferedIterable.this.iterable.iterator();

		List buffer = new ArrayList();

		public boolean hasNext() {
			if (this.buffer.isEmpty()) {
				this.fill();
			}
			return !this.buffer.isEmpty();
		}

		public E next() {
			if (!this.hasNext()) {
				throw new NoSuchElementException();
			}
			return this.buffer.remove(0);
		}

		public void remove() {
			throw new UnsupportedOperationException();
		}

		private void fill() {
			for (int i = 0; i < BufferedIterable.this.size; i++) {
				if (this.iterator.hasNext()) {
					this.buffer.add(this.iterator.next());
				} else {
					break;
				}
			}
		}
	}

	private Iterable iterable;

	private int size;

	public BufferedIterable(Iterable iterable) {
		this(iterable, DEFAULT_SIZE);
	}

	public BufferedIterable(Iterable iterable, int size) {
		if (iterable == null) {
			throw new IllegalArgumentException("iterable must be != null");
		}
		if (size <= 0) {
			throw new IllegalArgumentException("size must be > 0");
		}
		this.iterable = iterable;
		this.size = size;
	}

	public Iterator iterator() {
		return new IteratorImpl();
	}

}