//******************************************************************************
//
// File:    JobBackendMessage.java
// Package: edu.rit.pj.cluster
// Unit:    Class edu.rit.pj.cluster.JobBackendMessage
//
// This Java source file is copyright (C) 2007 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.pj.cluster;

import edu.rit.util.ByteSequence;

import java.io.IOException;
import java.io.Externalizable;
import java.io.ObjectInput;
import java.io.ObjectOutput;

import java.net.InetSocketAddress;

import java.util.Map;
import java.util.Properties;

/**
 * Class JobBackendMessage provides a message sent to a Job Backend process
 * (interface {@linkplain JobBackendRef}) in the PJ cluster middleware.
 *
 * @author  Alan Kaminsky
 * @version 02-Jul-2007
 */
public abstract class JobBackendMessage
	extends Message
	implements Externalizable
	{

// Hidden data members.

	private static final long serialVersionUID = 3747140854797048519L;

// Exported constructors.

	/**
	 * Construct a new job backend message.
	 */
	public JobBackendMessage()
		{
		}

	/**
	 * Construct a new job backend message with the given message tag.
	 *
	 * @param  theTag  Message tag to use when sending this message.
	 */
	public JobBackendMessage
		(int theTag)
		{
		super (theTag);
		}

// Exported operations.

	/**
	 * Construct a new "cancel job" message.
	 *
	 * @param  theJobFrontend  Job Frontend that is calling this method.
	 * @param  errmsg          Error message string.
	 *
	 * @return  "Cancel job" message.
	 */
	public static JobBackendMessage cancelJob
		(JobFrontendRef theJobFrontend,
		 String errmsg)
		{
		return new CancelJobMessage (theJobFrontend, errmsg);
		}

	/**
	 * Construct a new "commence job" message.
	 *
	 * @param  theJobFrontend
	 *     Job Frontend that is calling this method.
	 * @param  middlewareAddress
	 *     Array of hosts/ports for middleware messages. The first <I>K</I>
	 *     elements are for the job backend processes in rank order, the
	 *     <I>K</I>+1st element is for the job frontend process. If the
	 * @param  worldAddress
	 *     Array of hosts/ports for the world communicator. The <I>K</I>
	 *     elements are for the job backend processes in rank order.
	 * @param  frontendAddress
	 *     Array of hosts/ports for the frontend communicator. The first
	 *     <I>K</I> elements are for the job backend processes in rank order,
	 *     the <I>K</I>+1st element is for the job frontend process. If the
	 *     frontend communicator does not exist, <TT>frontendAddress</TT> is
	 *     null.
	 * @param  properties
	 *     Java system properties.
	 * @param  mainClassName
	 *     Fully qualified class name of the Java main program class to execute.
	 * @param  args
	 *     Array of 0 or more Java command line arguments.
	 *
	 * @return  "Commence job" message.
	 */
	public static JobBackendMessage commenceJob
		(JobFrontendRef theJobFrontend,
		 InetSocketAddress[] middlewareAddress,
		 InetSocketAddress[] worldAddress,
		 InetSocketAddress[] frontendAddress,
		 Properties properties,
		 String mainClassName,
		 String[] args)
		{
		return new CommenceJobMessage
			(theJobFrontend, middlewareAddress, worldAddress, frontendAddress,
			 properties, mainClassName, args);
		}

	/**
	 * Construct a new "job finished" message.
	 *
	 * @param  theJobFrontend  Job frontend that is calling this method.
	 *
	 * @return  "Job finished" message.
	 */
	public static JobBackendMessage jobFinished
		(JobFrontendRef theJobFrontend)
		{
		return new JobFinishedMessage (theJobFrontend);
		}

	/**
	 * Construct a new "renew lease" message.
	 *
	 * @param  theJobFrontend  Job Frontend that is calling this method.
	 *
	 * @return  "Renew lease" message.
	 */
	public static JobBackendMessage renewLease
		(JobFrontendRef theJobFrontend)
		{
		return new RenewLeaseMessage (theJobFrontend);
		}

	/**
	 * Construct a new "report resource" message.
	 *
	 * @param  theJobFrontend  Job Frontend that is calling this method.
	 * @param  resourceName    Resource name.
	 * @param  content         Resource content, or null if resource not found.
	 *
	 * @return  "Report resource" message.
	 */
	public static JobBackendMessage reportResource
		(JobFrontendRef theJobFrontend,
		 String resourceName,
		 byte[] content)
		{
		return new ReportResourceMessage
			(theJobFrontend, resourceName, content);
		}

	/**
	 * Construct a new "report resource" message.
	 *
	 * @param  theJobFrontend  Job Frontend that is calling this method.
	 * @param  resourceName    Resource name.
	 * @param  content         Resource content, or null if resource not found.
	 *
	 * @return  "Report resource" message.
	 */
	public static JobBackendMessage reportResource
		(JobFrontendRef theJobFrontend,
		 String resourceName,
		 ByteSequence content)
		{
		return new ReportResourceMessage
			(theJobFrontend, resourceName, content);
		}

	/**
	 * Construct a new "output file open result" message.
	 *
	 * @param  theJobFrontend  Job Frontend that is calling this method.
	 * @param  bfd             Backend file descriptor.
	 * @param  ffd             Frontend file descriptor if success.
	 * @param  exc             Null if success, exception if failure.
	 *
	 * @return  "Output file open result" message.
	 */
	public static JobBackendMessage outputFileOpenResult
		(JobFrontendRef theJobFrontend,
		 int bfd,
		 int ffd,
		 IOException exc)
		{
		return new OutputFileOpenResultMessage (theJobFrontend, bfd, ffd, exc);
		}

	/**
	 * Construct a new "output file write result" message.
	 *
	 * @param  theJobFrontend  Job Frontend that is calling this method.
	 * @param  ffd             Frontend file descriptor.
	 * @param  exc             Null if success, exception if failure.
	 *
	 * @return  "Output file write result" message.
	 */
	public static JobBackendMessage outputFileWriteResult
		(JobFrontendRef theJobFrontend,
		 int ffd,
		 IOException exc)
		{
		return new OutputFileWriteResultMessage (theJobFrontend, ffd, exc);
		}

	/**
	 * Construct a new "output file flush result" message.
	 *
	 * @param  theJobFrontend  Job Frontend that is calling this method.
	 * @param  ffd             Frontend file descriptor.
	 * @param  exc             Null if success, exception if failure.
	 *
	 * @return  "Output file flush result" message.
	 */
	public static JobBackendMessage outputFileFlushResult
		(JobFrontendRef theJobFrontend,
		 int ffd,
		 IOException exc)
		{
		return new OutputFileFlushResultMessage (theJobFrontend, ffd, exc);
		}

	/**
	 * Construct a new "output file close result" message.
	 *
	 * @param  theJobFrontend  Job Frontend that is calling this method.
	 * @param  ffd             Frontend file descriptor.
	 * @param  exc             Null if success, exception if failure.
	 *
	 * @return  "Output file close result" message.
	 */
	public static JobBackendMessage outputFileCloseResult
		(JobFrontendRef theJobFrontend,
		 int ffd,
		 IOException exc)
		{
		return new OutputFileCloseResultMessage (theJobFrontend, ffd, exc);
		}

	/**
	 * Construct a new "input file open result" message.
	 *
	 * @param  theJobFrontend  Job Frontend that is calling this method.
	 * @param  bfd             Backend file descriptor.
	 * @param  ffd             Frontend file descriptor if success.
	 * @param  exc             Null if success, exception if failure.
	 *
	 * @return  "Input file open result" message.
	 */
	public static JobBackendMessage inputFileOpenResult
		(JobFrontendRef theJobFrontend,
		 int bfd,
		 int ffd,
		 IOException exc)
		{
		return new InputFileOpenResultMessage (theJobFrontend, bfd, ffd, exc);
		}

	/**
	 * Construct a new "input file read result" message.
	 *
	 * @param  theJobFrontend  Job Frontend that is calling this method.
	 * @param  ffd             Frontend file descriptor.
	 * @param  len             Number of bytes read, or -1 if EOF.
	 * @param  exc             Null if success, exception if failure.
	 *
	 * @return  "Input file read result" message.
	 */
	public static JobBackendMessage inputFileReadResult
		(JobFrontendRef theJobFrontend,
		 int ffd,
		 int len,
		 IOException exc)
		{
		return new InputFileReadResultMessage (theJobFrontend, ffd, len, exc);
		}

	/**
	 * Construct a new "input file skip result" message.
	 *
	 * @param  theJobFrontend  Job Frontend that is calling this method.
	 * @param  ffd             Frontend file descriptor.
	 * @param  len             Number of bytes skipped.
	 * @param  exc             Null if success, exception if failure.
	 *
	 * @return  "Input file skip result" message.
	 */
	public static JobBackendMessage inputFileSkipResult
		(JobFrontendRef theJobFrontend,
		 int ffd,
		 long len,
		 IOException exc)
		{
		return new InputFileSkipResultMessage (theJobFrontend, ffd, len, exc);
		}

	/**
	 * Construct a new "input file close result" message.
	 *
	 * @param  theJobFrontend  Job Frontend that is calling this method.
	 * @param  ffd             Frontend file descriptor.
	 * @param  exc             Null if success, exception if failure.
	 *
	 * @return  "Input file close result" message.
	 */
	public static JobBackendMessage inputFileCloseResult
		(JobFrontendRef theJobFrontend,
		 int ffd,
		 IOException exc)
		{
		return new InputFileCloseResultMessage (theJobFrontend, ffd, exc);
		}

	/**
	 * Invoke the method corresponding to this job backend message on the
	 * given Job Backend object. The method arguments come from the fields of
	 * this job backend message object.
	 *
	 * @param  theJobBackend   Job Backend on which to invoke the method.
	 * @param  theJobFrontend  Job Frontend that is calling the method.
	 *
	 * @exception  IOException
	 *     Thrown if an I/O error occurred.
	 */
	public void invoke
		(JobBackendRef theJobBackend,
		 JobFrontendRef theJobFrontend)
		throws IOException
		{
		throw new UnsupportedOperationException();
		}

	/**
	 * Write this job backend message to the given object output stream.
	 *
	 * @param  out  Object output stream.
	 *
	 * @exception  IOException
	 *     Thrown if an I/O error occurred.
	 */
	public void writeExternal
		(ObjectOutput out)
		throws IOException
		{
		}

	/**
	 * Read this job backend message from the given object input stream.
	 *
	 * @param  in  Object input stream.
	 *
	 * @exception  IOException
	 *     Thrown if an I/O error occurred.
	 * @exception  ClassNotFoundException
	 *     Thrown if a class needed to read this job backend message could not
	 *     be found.
	 */
	public void readExternal
		(ObjectInput in)
		throws IOException, ClassNotFoundException
		{
		}

// Hidden subclasses.

	/**
	 * Class CancelJobMessage provides the Job Backend "cancel job" message in
	 * the PJ cluster middleware.
	 *
	 * @author  Alan Kaminsky
	 * @version 25-Oct-2006
	 */
	private static class CancelJobMessage
		extends JobBackendMessage
		{
		private static final long serialVersionUID = -1706674774429384654L;

		private String errmsg;

		public CancelJobMessage()
			{
			}

		public CancelJobMessage
			(JobFrontendRef theJobFrontend,
			 String errmsg)
			{
			super (Message.FROM_JOB_FRONTEND);
			this.errmsg = errmsg;
			}

		public void invoke
			(JobBackendRef theJobBackend,
			 JobFrontendRef theJobFrontend)
			throws IOException
			{
			theJobBackend.cancelJob (theJobFrontend, errmsg);
			}

		public void writeExternal
			(ObjectOutput out)
			throws IOException
			{
			out.writeUTF (errmsg);
			}

		public void readExternal
			(ObjectInput in)
			throws IOException
			{
			errmsg = in.readUTF();
			}
		}

	/**
	 * Class CommenceJobMessage provides the Job Backend "commence job" message
	 * in the PJ cluster middleware.
	 *
	 * @author  Alan Kaminsky
	 * @version 25-Oct-2006
	 */
	private static class CommenceJobMessage
		extends JobBackendMessage
		{
		private static final long serialVersionUID = -8262872991140404870L;

		private InetSocketAddress[] middlewareAddress;
		private InetSocketAddress[] worldAddress;
		private InetSocketAddress[] frontendAddress;
		private Properties properties;
		private String mainClassName;
		private String[] args;

		public CommenceJobMessage()
			{
			}

		public CommenceJobMessage
			(JobFrontendRef theJobFrontend,
			 InetSocketAddress[] middlewareAddress,
			 InetSocketAddress[] worldAddress,
			 InetSocketAddress[] frontendAddress,
			 Properties properties,
			 String mainClassName,
			 String[] args)
			{
			super (Message.FROM_JOB_FRONTEND);
			this.middlewareAddress = middlewareAddress;
			this.worldAddress = worldAddress;
			this.frontendAddress = frontendAddress;
			this.properties = properties;
			this.mainClassName = mainClassName;
			this.args = args;
			}

		public void invoke
			(JobBackendRef theJobBackend,
			 JobFrontendRef theJobFrontend)
			throws IOException
			{
			theJobBackend.commenceJob
				(theJobFrontend, middlewareAddress, worldAddress,
				 frontendAddress, properties, mainClassName, args);
			}

		public void writeExternal
			(ObjectOutput out)
			throws IOException
			{
			out.writeInt (properties.size());
			for (Map.Entry<Object,Object> entry : properties.entrySet())
				{
				out.writeUTF ((String) entry.getKey());
				out.writeUTF ((String) entry.getValue());
				}
			out.writeUTF (mainClassName);
			out.writeInt (args.length);
			for (String arg : args)
				{
				out.writeUTF (arg);
				}
			int n1 = middlewareAddress.length;
			int n2 = worldAddress.length;
			int n3 = frontendAddress == null ? 0 : frontendAddress.length;
			out.writeInt (n1);
			out.writeInt (n2);
			out.writeInt (n3);
			for (int i = 0; i < n1; ++ i)
				{
				out.writeObject (middlewareAddress[i]);
				}
			for (int i = 0; i < n2; ++ i)
				{
				out.writeObject (worldAddress[i]);
				}
			for (int i = 0; i < n3; ++ i)
				{
				out.writeObject (frontendAddress[i]);
				}
			}

		public void readExternal
			(ObjectInput in)
			throws IOException, ClassNotFoundException
			{
			int n = in.readInt();
			properties = new Properties();
			for (int i = 0; i < n; ++ i)
				{
				properties.setProperty (in.readUTF(), in.readUTF());
				}
			mainClassName = in.readUTF();
			n = in.readInt();
			args = new String [n];
			for (int i = 0; i < n; ++ i)
				{
				args[i] = in.readUTF();
				}
			int n1 = in.readInt();
			int n2 = in.readInt();
			int n3 = in.readInt();
			middlewareAddress = new InetSocketAddress [n1];
			for (int i = 0; i < n1; ++ i)
				{
				middlewareAddress[i] = (InetSocketAddress) in.readObject();
				}
			worldAddress = new InetSocketAddress [n2];
			for (int i = 0; i < n2; ++ i)
				{
				worldAddress[i] = (InetSocketAddress) in.readObject();
				}
			if (n3 > 0)
				{
				frontendAddress = new InetSocketAddress [n3];
				for (int i = 0; i < n3; ++ i)
					{
					frontendAddress[i] = (InetSocketAddress) in.readObject();
					}
				}
			}
		}

	/**
	 * Class JobFinishedMessage provides the Job Backend "job finished" message
	 * in the PJ cluster middleware.
	 *
	 * @author  Alan Kaminsky
	 * @version 26-Oct-2006
	 */
	private static class JobFinishedMessage
		extends JobBackendMessage
		{
		private static final long serialVersionUID = 1363549433797859519L;

		public JobFinishedMessage()
			{
			}

		public JobFinishedMessage
			(JobFrontendRef theJobFrontend)
			{
			super (Message.FROM_JOB_FRONTEND);
			}

		public void invoke
			(JobBackendRef theJobBackend,
			 JobFrontendRef theJobFrontend)
			throws IOException
			{
			theJobBackend.jobFinished (theJobFrontend);
			}
		}

	/**
	 * Class RenewLeaseMessage provides the Job Backend "renew lease" message
	 * in the PJ cluster middleware.
	 *
	 * @author  Alan Kaminsky
	 * @version 25-Oct-2006
	 */
	private static class RenewLeaseMessage
		extends JobBackendMessage
		{
		private static final long serialVersionUID = -5146916532326180730L;

		public RenewLeaseMessage()
			{
			}

		public RenewLeaseMessage
			(JobFrontendRef theJobFrontend)
			{
			super (Message.FROM_JOB_FRONTEND);
			}

		public void invoke
			(JobBackendRef theJobBackend,
			 JobFrontendRef theJobFrontend)
			throws IOException
			{
			theJobBackend.renewLease (theJobFrontend);
			}
		}

	/**
	 * Class ReportResourceMessage provides the Job Backend "report resource"
	 * message in the PJ cluster middleware.
	 *
	 * @author  Alan Kaminsky
	 * @version 26-Oct-2006
	 */
	private static class ReportResourceMessage
		extends JobBackendMessage
		{
		private static final long serialVersionUID = 8709827200639757997L;

		private String resourceName;
		private ByteSequence contentSeq;
		private byte[] content;

		public ReportResourceMessage()
			{
			}

		public ReportResourceMessage
			(JobFrontendRef theJobFrontend,
			 String resourceName,
			 byte[] content)
			{
			super (Message.FROM_JOB_FRONTEND);
			this.resourceName = resourceName;
			this.content = content;
			}

		public ReportResourceMessage
			(JobFrontendRef theJobFrontend,
			 String resourceName,
			 ByteSequence content)
			{
			super (Message.FROM_JOB_FRONTEND);
			this.resourceName = resourceName;
			this.contentSeq = content;
			}

		public void invoke
			(JobBackendRef theJobBackend,
			 JobFrontendRef theJobFrontend)
			throws IOException
			{
			if (content != null)
				{
				theJobBackend.reportResource
					(theJobFrontend, resourceName, content);
				}
			else
				{
				theJobBackend.reportResource
					(theJobFrontend, resourceName, contentSeq);
				}
			}

		public void writeExternal
			(ObjectOutput out)
			throws IOException
			{
			out.writeUTF (resourceName);
			if (content != null)
				{
				out.writeInt (content.length);
				out.write (content);
				}
			else if (contentSeq != null)
				{
				out.writeInt (contentSeq.length());
				contentSeq.write (out);
				}
			else
				{
				out.writeInt (-1);
				}
			}

		public void readExternal
			(ObjectInput in)
			throws IOException
			{
			resourceName = in.readUTF();
			int n = in.readInt();
			if (n < 0)
				{
				content = null;
				}
			else
				{
				content = new byte [n];
				in.readFully (content);
				}
			}
		}

	/**
	 * Class OutputFileOpenResultMessage provides the Job Backend "output file
	 * open result" message in the PJ cluster middleware.
	 *
	 * @author  Alan Kaminsky
	 * @version 05-Nov-2006
	 */
	private static class OutputFileOpenResultMessage
		extends JobBackendMessage
		{
		private static final long serialVersionUID = 1460222094425830409L;

		private int bfd;
		private int ffd;
		private IOException exc;

		public OutputFileOpenResultMessage()
			{
			}

		public OutputFileOpenResultMessage
			(JobFrontendRef theJobFrontend,
			 int bfd,
			 int ffd,
			 IOException exc)
			{
			super (Message.FROM_JOB_FRONTEND);
			this.bfd = bfd;
			this.ffd = ffd;
			this.exc = exc;
			}

		public void invoke
			(JobBackendRef theJobBackend,
			 JobFrontendRef theJobFrontend)
			throws IOException
			{
			theJobBackend.outputFileOpenResult (theJobFrontend, bfd, ffd, exc);
			}

		public void writeExternal
			(ObjectOutput out)
			throws IOException
			{
			out.writeInt (bfd);
			out.writeInt (ffd);
			out.writeObject (exc);
			}

		public void readExternal
			(ObjectInput in)
			throws IOException, ClassNotFoundException
			{
			bfd = in.readInt();
			ffd = in.readInt();
			exc = (IOException) in.readObject();
			}
		}

	/**
	 * Class OutputFileWriteResultMessage provides the Job Backend "output file
	 * write result" message in the PJ cluster middleware.
	 *
	 * @author  Alan Kaminsky
	 * @version 05-Nov-2006
	 */
	private static class OutputFileWriteResultMessage
		extends JobBackendMessage
		{
		private static final long serialVersionUID = -4734876024127370851L;

		private int ffd;
		private IOException exc;

		public OutputFileWriteResultMessage()
			{
			}

		public OutputFileWriteResultMessage
			(JobFrontendRef theJobFrontend,
			 int ffd,
			 IOException exc)
			{
			super (Message.FROM_JOB_FRONTEND);
			this.ffd = ffd;
			this.exc = exc;
			}

		public void invoke
			(JobBackendRef theJobBackend,
			 JobFrontendRef theJobFrontend)
			throws IOException
			{
			theJobBackend.outputFileWriteResult (theJobFrontend, ffd, exc);
			}

		public void writeExternal
			(ObjectOutput out)
			throws IOException
			{
			out.writeInt (ffd);
			out.writeObject (exc);
			}

		public void readExternal
			(ObjectInput in)
			throws IOException, ClassNotFoundException
			{
			ffd = in.readInt();
			exc = (IOException) in.readObject();
			}
		}

	/**
	 * Class OutputFileFlushResultMessage provides the Job Backend "output file
	 * flush result" message in the PJ cluster middleware.
	 *
	 * @author  Alan Kaminsky
	 * @version 05-Nov-2006
	 */
	private static class OutputFileFlushResultMessage
		extends JobBackendMessage
		{
		private static final long serialVersionUID = 8921581871627030306L;

		private int ffd;
		private IOException exc;

		public OutputFileFlushResultMessage()
			{
			}

		public OutputFileFlushResultMessage
			(JobFrontendRef theJobFrontend,
			 int ffd,
			 IOException exc)
			{
			super (Message.FROM_JOB_FRONTEND);
			this.ffd = ffd;
			this.exc = exc;
			}

		public void invoke
			(JobBackendRef theJobBackend,
			 JobFrontendRef theJobFrontend)
			throws IOException
			{
			theJobBackend.outputFileFlushResult (theJobFrontend, ffd, exc);
			}

		public void writeExternal
			(ObjectOutput out)
			throws IOException
			{
			out.writeInt (ffd);
			out.writeObject (exc);
			}

		public void readExternal
			(ObjectInput in)
			throws IOException, ClassNotFoundException
			{
			ffd = in.readInt();
			exc = (IOException) in.readObject();
			}
		}

	/**
	 * Class OutputFileCloseResultMessage provides the Job Backend "output file
	 * close result" message in the PJ cluster middleware.
	 *
	 * @author  Alan Kaminsky
	 * @version 05-Nov-2006
	 */
	private static class OutputFileCloseResultMessage
		extends JobBackendMessage
		{
		private static final long serialVersionUID = 5976163600237430235L;

		private int ffd;
		private IOException exc;

		public OutputFileCloseResultMessage()
			{
			}

		public OutputFileCloseResultMessage
			(JobFrontendRef theJobFrontend,
			 int ffd,
			 IOException exc)
			{
			super (Message.FROM_JOB_FRONTEND);
			this.ffd = ffd;
			this.exc = exc;
			}

		public void invoke
			(JobBackendRef theJobBackend,
			 JobFrontendRef theJobFrontend)
			throws IOException
			{
			theJobBackend.outputFileCloseResult (theJobFrontend, ffd, exc);
			}

		public void writeExternal
			(ObjectOutput out)
			throws IOException
			{
			out.writeInt (ffd);
			out.writeObject (exc);
			}

		public void readExternal
			(ObjectInput in)
			throws IOException, ClassNotFoundException
			{
			ffd = in.readInt();
			exc = (IOException) in.readObject();
			}
		}

	/**
	 * Class InputFileOpenResultMessage provides the Job Backend "input file
	 * open result" message in the PJ cluster middleware.
	 *
	 * @author  Alan Kaminsky
	 * @version 05-Nov-2006
	 */
	private static class InputFileOpenResultMessage
		extends JobBackendMessage
		{
		private static final long serialVersionUID = -1082499193559062581L;

		private int bfd;
		private int ffd;
		private IOException exc;

		public InputFileOpenResultMessage()
			{
			}

		public InputFileOpenResultMessage
			(JobFrontendRef theJobFrontend,
			 int bfd,
			 int ffd,
			 IOException exc)
			{
			super (Message.FROM_JOB_FRONTEND);
			this.bfd = bfd;
			this.ffd = ffd;
			this.exc = exc;
			}

		public void invoke
			(JobBackendRef theJobBackend,
			 JobFrontendRef theJobFrontend)
			throws IOException
			{
			theJobBackend.inputFileOpenResult (theJobFrontend, bfd, ffd, exc);
			}

		public void writeExternal
			(ObjectOutput out)
			throws IOException
			{
			out.writeInt (bfd);
			out.writeInt (ffd);
			out.writeObject (exc);
			}

		public void readExternal
			(ObjectInput in)
			throws IOException, ClassNotFoundException
			{
			bfd = in.readInt();
			ffd = in.readInt();
			exc = (IOException) in.readObject();
			}
		}

	/**
	 * Class InputFileReadResultMessage provides the Job Backend "input file
	 * read result" message in the PJ cluster middleware.
	 *
	 * @author  Alan Kaminsky
	 * @version 20-Nov-2006
	 */
	private static class InputFileReadResultMessage
		extends JobBackendMessage
		{
		private static final long serialVersionUID = 4542261695089387333L;

		private int ffd;
		private int len;
		private IOException exc;

		public InputFileReadResultMessage()
			{
			}

		public InputFileReadResultMessage
			(JobFrontendRef theJobFrontend,
			 int ffd,
			 int len,
			 IOException exc)
			{
			super (Message.FROM_JOB_FRONTEND);
			this.ffd = ffd;
			this.len = len;
			this.exc = exc;
			}

		public void invoke
			(JobBackendRef theJobBackend,
			 JobFrontendRef theJobFrontend)
			throws IOException
			{
			theJobBackend.inputFileReadResult
				(theJobFrontend, ffd, null, len, exc);
			}

		public void writeExternal
			(ObjectOutput out)
			throws IOException
			{
			out.writeInt (ffd);
			out.writeInt (len);
			out.writeObject (exc);
			}

		public void readExternal
			(ObjectInput in)
			throws IOException, ClassNotFoundException
			{
			ffd = in.readInt();
			len = in.readInt();
			exc = (IOException) in.readObject();
			}
		}

	/**
	 * Class InputFileSkipResultMessage provides the Job Backend "input file
	 * skip result" message in the PJ cluster middleware.
	 *
	 * @author  Alan Kaminsky
	 * @version 05-Nov-2006
	 */
	private static class InputFileSkipResultMessage
		extends JobBackendMessage
		{
		private static final long serialVersionUID = 5050948958179612039L;

		private int ffd;
		private long len;
		private IOException exc;

		public InputFileSkipResultMessage()
			{
			}

		public InputFileSkipResultMessage
			(JobFrontendRef theJobFrontend,
			 int ffd,
			 long len,
			 IOException exc)
			{
			super (Message.FROM_JOB_FRONTEND);
			this.ffd = ffd;
			this.len = len;
			this.exc = exc;
			}

		public void invoke
			(JobBackendRef theJobBackend,
			 JobFrontendRef theJobFrontend)
			throws IOException
			{
			theJobBackend.inputFileSkipResult (theJobFrontend, ffd, len, exc);
			}

		public void writeExternal
			(ObjectOutput out)
			throws IOException
			{
			out.writeInt (ffd);
			out.writeLong (len);
			out.writeObject (exc);
			}

		public void readExternal
			(ObjectInput in)
			throws IOException, ClassNotFoundException
			{
			ffd = in.readInt();
			len = in.readLong();
			exc = (IOException) in.readObject();
			}
		}

	/**
	 * Class InputFileCloseResultMessage provides the Job Backend "input file
	 * close result" message in the PJ cluster middleware.
	 *
	 * @author  Alan Kaminsky
	 * @version 05-Nov-2006
	 */
	private static class InputFileCloseResultMessage
		extends JobBackendMessage
		{
		private static final long serialVersionUID = -5645040374361899565L;

		private int ffd;
		private IOException exc;

		public InputFileCloseResultMessage()
			{
			}

		public InputFileCloseResultMessage
			(JobFrontendRef theJobFrontend,
			 int ffd,
			 IOException exc)
			{
			super (Message.FROM_JOB_FRONTEND);
			this.ffd = ffd;
			this.exc = exc;
			}

		public void invoke
			(JobBackendRef theJobBackend,
			 JobFrontendRef theJobFrontend)
			throws IOException
			{
			theJobBackend.inputFileCloseResult (theJobFrontend, ffd, exc);
			}

		public void writeExternal
			(ObjectOutput out)
			throws IOException
			{
			out.writeInt (ffd);
			out.writeObject (exc);
			}

		public void readExternal
			(ObjectInput in)
			throws IOException, ClassNotFoundException
			{
			ffd = in.readInt();
			exc = (IOException) in.readObject();
			}
		}

	}