//******************************************************************************
//
// File:    IORequestList.java
// Package: edu.rit.mp
// Unit:    Class edu.rit.mp.IORequestList
//
// This Java source file is copyright (C) 2006 by Alan Kaminsky. All rights
// reserved. For further information, contact the author, Alan Kaminsky, at
// ark@cs.rit.edu.
//
// This Java source file is part of the Parallel Java Library ("PJ"). PJ is free
// software; you can redistribute it and/or modify it under the terms of the GNU
// General Public License as published by the Free Software Foundation; either
// version 3 of the License, or (at your option) any later version.
//
// PJ 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 General Public License for more details.
//
// Linking this library statically or dynamically with other modules is making a
// combined work based on this library. Thus, the terms and conditions of the
// GNU General Public License cover the whole combination.
//
// As a special exception, the copyright holders of this library give you
// permission to link this library with independent modules to produce an
// executable, regardless of the license terms of these independent modules, and
// to copy and distribute the resulting executable under terms of your choice,
// provided that you also meet, for each linked independent module, the terms
// and conditions of the license of that module. An independent module is a
// module which is not derived from or based on this library. If you modify this
// library, you may extend this exception to your version of the library, but
// you are not obligated to do so. If you do not wish to do so, delete this
// exception statement from your version.
//
// A copy of the GNU General Public License is provided in the file gpl.txt. You
// may also obtain a copy of the GNU General Public License on the World Wide
// Web at http://www.gnu.org/licenses/gpl.html.
//
//******************************************************************************

package edu.rit.mp;

import java.io.IOException;
import java.io.PrintStream;

import java.util.Iterator;
import java.util.LinkedList;

/**
 * Class IORequestList provides a list of pending I/O requests in the Message
 * Protocol (MP).
 *
 * @author  Alan Kaminsky
 * @version 26-Oct-2006
 */
class IORequestList
	{

// Hidden data members.

	LinkedList<IORequest> myList = new LinkedList<IORequest>();

// Exported constructors.

	/**
	 * Construct a new I/O request list.
	 */
	public IORequestList()
		{
		}

// Exported operations.

	/**
	 * Add the given I/O request to this list. This list maintains the I/O
	 * requests in FIFO order.
	 *
	 * @param  theIORequest  I/O request.
	 */
	public synchronized void add
		(IORequest theIORequest)
		{
		myList.add (theIORequest);
		notifyAll();
		}

	/**
	 * Remove an I/O request from this list that matches the given I/O request.
	 * The first matching I/O request, if any, is returned.
	 *
	 * @param  theIORequest  I/O request.
	 *
	 * @return  Matching I/O request removed from this list, or null if there
	 *          was no match.
	 */
	public synchronized IORequest removeMatch
		(IORequest theIORequest)
		{
		Iterator<IORequest> iter = myList.iterator();
		while (iter.hasNext())
			{
			IORequest iorequest = iter.next();
			if (iorequest.match (theIORequest))
				{
				iter.remove();
				return iorequest;
				}
			}
		return null;
		}

	/**
	 * Remove an I/O request from this list that matches the given channel,
	 * message tag, and message type. The first matching I/O request, if any, is
	 * returned.
	 *
	 * @param  channel  Channel.
	 * @param  tag      Message tag.
	 * @param  type     Message type.
	 *
	 * @return  Matching I/O request removed from this list, or null if there
	 *          was no match.
	 */
	public synchronized IORequest removeMatch
		(Channel channel,
		 Integer tag,
		 byte type)
		{
		Iterator<IORequest> iter = myList.iterator();
		while (iter.hasNext())
			{
			IORequest iorequest = iter.next();
			if (iorequest.match (channel, tag, type))
				{
				iter.remove();
				return iorequest;
				}
			}
		return null;
		}

	/**
	 * Wait for an I/O request that matches the given I/O request to be added to
	 * this list, then remove it. The first matching I/O request is returned.
	 *
	 * @param  theIORequest  I/O request.
	 *
	 * @return  Matching I/O request removed from this list.
	 *
	 * @exception  InterruptedException
	 *     Thrown if the calling thread was interrupted while blocked in this
	 *     method.
	 */
	public synchronized IORequest waitForMatch
		(IORequest theIORequest)
		throws InterruptedException
		{
		IORequest iorequest;
		while ((iorequest = removeMatch (theIORequest)) == null)
			{
//System.out.println ("IORequest.waitForMatch("+theIORequest+") waiting, myList="+this);
			wait();
			}
		return iorequest;
		}

	/**
	 * Wait for an I/O request that matches the given channel, message tag, and
	 * message type to be added to this list, then remove it. The first matching
	 * I/O request is returned.
	 *
	 * @param  theIORequest  I/O request.
	 *
	 * @return  Matching I/O request removed from this list.
	 *
	 * @exception  InterruptedException
	 *     Thrown if the calling thread was interrupted while blocked in this
	 *     method.
	 */
	public synchronized IORequest waitForMatch
		(Channel channel,
		 Integer tag,
		 byte type)
		throws InterruptedException
		{
		IORequest iorequest;
		while ((iorequest = removeMatch (channel, tag, type)) == null)
			{
//System.out.println ("IORequest.waitForMatch("+channel+","+tag+","+type+") waiting, myList="+this);
			wait();
			}
		return iorequest;
		}

	/**
	 * Report that every I/O request in this list failed with an I/O exception.
	 *
	 * @param  theIOException  I/O exception.
	 */
	public synchronized void reportFailure
		(IOException theIOException)
		{
		IORequest iorequest = null;
		while (! myList.isEmpty())
			{
			iorequest = myList.remove (0);
			iorequest.reportFailure (theIOException);
			}
		}

	/**
	 * Dump the state of this I/O request list on the given print stream. For
	 * debugging.
	 *
	 * @param  out     Print stream.
	 * @param  prefix  String to print at the beginning of each line.
	 */
	public synchronized void dump
		(PrintStream out,
		 String prefix)
		{
		out.println (prefix+getClass().getName()+"@"+Integer.toHexString(System.identityHashCode(this)));
		out.println (prefix+"\t"+myList.size()+" entries");
		for (IORequest r : myList)
			{
			out.println (prefix+"\t"+r);
			}
		}

	}
