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Rule base analysis for InteGraal. This is imported from Graal
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/*
 * Copyright (C) Inria Sophia Antipolis - Méditerranée / LIRMM
 * (Université de Montpellier & CNRS) (2014 - 2017)
 *
 * Contributors :
 *
 * Clément SIPIETER 
 * Mélanie KÖNIG
 * Swan ROCHER
 * Jean-François BAGET
 * Michel LECLÈRE
 * Marie-Laure MUGNIER 
 *
 *
 * This file is part of Graal .
 *
 * This software is governed by the CeCILL  license under French law and
 * abiding by the rules of distribution of free software.  You can  use,
 * modify and/ or redistribute the software under the terms of the CeCILL
 * license as circulated by CEA, CNRS and INRIA at the following URL
 * "http://www.cecill.info".
 *
 * As a counterpart to the access to the source code and  rights to copy,
 * modify and redistribute granted by the license, users are provided only
 * with a limited warranty  and the software's author,  the holder of the
 * economic rights,  and the successive licensors  have only  limited
 * liability.
 *
 * In this respect, the user's attention is drawn to the risks associated
 * with loading,  using,  modifying and/or developing or reproducing the
 * software by the user in light of its specific status of free software,
 * that may mean  that it is complicated to manipulate,  and  that  also
 * therefore means  that it is reserved for developers  and  experienced
 * professionals having in-depth computer knowledge. Users are therefore
 * encouraged to load and test the software's suitability as regards their
 * requirements in conditions enabling the security of their systems and/or
 * data to be ensured and,  more generally, to use and operate it in the
 * same conditions as regards security.
 *
 * The fact that you are presently reading this means that you have had
 * knowledge of the CeCILL license and that you accept its terms.
 */
 /**
 * 
 */
package fr.lirmm.graphik.util.stream;

import java.io.IOException;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.Queue;

/**
 * @author Clément Sipieter (INRIA) [email protected]
 *
 */
public class LinkedBlockingStream extends AbstractCloseableIterator implements Writer {

    final int MAX_QUEUE;
    final int MIN_QUEUE;
    
    private final Object lock;
    private final Queue queue = new LinkedList();
    private boolean isOpen = true;

    // /////////////////////////////////////////////////////////////////////////
    //	CONSTRUCTORS
    // /////////////////////////////////////////////////////////////////////////

    public LinkedBlockingStream() {
        this.MAX_QUEUE = 1024;
        this.MIN_QUEUE = 32;
        this.lock = new Object();
    }
    
    // /////////////////////////////////////////////////////////////////////////
    //	METHODS
    // /////////////////////////////////////////////////////////////////////////

    @Override
    public  void write(T object) {
    	synchronized(lock) {
            while(this.isOpen && this.queue.size() >= MAX_QUEUE ) {
                try {
                    lock.wait();
                } catch (InterruptedException e) {
                }
            }
            this.queue.add(object);
            lock.notifyAll();
    	}
    }

    @Override
    public boolean hasNext() {
    	synchronized(lock) {
            while(this.isOpen && this.queue.size() == 0) {
                try {
                    lock.wait();
                } catch (InterruptedException e) {
                }
            }
                   
            return !this.queue.isEmpty();
    	}
    }
    
    @Override
    public T next() {
    	synchronized(lock) {
            this.hasNext();
            T object = this.queue.poll();
            
            if(this.queue.size() <= MIN_QUEUE)
                lock.notifyAll();
            
            return object;
    	}
    }

    @Override
    public void close(){
    	synchronized(lock) {
    		this.isOpen = false;
    		lock.notifyAll();
    	}
    }

    @Override
	public void write(Iterator it) throws IOException {
		while (it.hasNext())
			this.write(it.next());
    }



}