//******************************************************************************
//
// File:    BackendInfo.java
// Package: edu.rit.pj.cluster
// Unit:    Class edu.rit.pj.cluster.BackendInfo
//
// This Java source file is copyright (C) 2008 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.
//
// 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 java.util.LinkedList;
import java.util.List;

/**
 * Class BackendInfo provides a record of information about one backend node in
 * the PJ cluster middleware.
 *
 * @author  Alan Kaminsky
 * @version 21-May-2008
 */
public class BackendInfo
	{

// Exported enumerations.

	/**
	 * The state of a backend node.
	 */
	public static enum State
		{
		/**
		 * The backend is available for jobs.
		 */
		IDLE ("Idle"),

		/**
		 * The backend is reserved for a job that has not yet started running.
		 */
		RESERVED ("Reserved"),

		/**
		 * The backend is running a job.
		 */
		RUNNING ("Running"),

		/**
		 * The backend has failed.
		 */
		FAILED ("Failed");

		private final String stringForm;

		/**
		 * Construct a new State value.
		 *
		 * @param  stringForm  String form.
		 */
		State
			(String stringForm)
			{
			this.stringForm = stringForm;
			}

		/**
		 * Returns a string version of this State value.
		 *
		 * @return  String version.
		 */
		public String toString()
			{
			return stringForm;
			}
		}

// Exported data members.

	/**
	 * The backend's name.
	 */
	public String name;

	/**
	 * The total number of CPUs in the backend.
	 */
	public int totalCpus;

	/**
	 * The backend's state.
	 */
	public State state;

	/**
	 * The time when the backend entered its current state (milliseconds since
	 * midnight 01-Jan-1970 GMT).
	 */
	public long stateTime;

	/**
	 * The host name for SSH remote logins to the backend.
	 */
	public String host;

	/**
	 * The full pathname for executing the Java Virtual Machine (JVM) on the
	 * backend.
	 */
	public String jvm;

	/**
	 * The Java class path for the Parallel Java Library on the backend.
	 */
	public String classpath;

	/**
	 * Array of command line flags for the JVM (zero or more).
	 */
	public String[] jvmflags;

	/**
	 * The job that has reserved or is running on the backend.
	 */
	public JobInfo job;

// Exported constructors.

	/**
	 * Construct a new backend information record.
	 *
	 * @param  name           The backend's name.
	 * @param  totalCpus      The total number of CPUs in the backend.
	 * @param  state          The backend's state.
	 * @param  stateTime      The time when the backend entered its current
	 *                        state.
	 * @param  host           The host name for SSH remote logins to the
	 *                        backend.
	 * @param  jvm            The full pathname for executing the Java Virtual
	 *                        Machine (JVM) on the backend.
	 * @param  classpath      The Java class path for the Parallel Java Library
	 *                        on the backend.
	 * @param  jvmflags       Array of command line flags for the JVM (zero or
	 *                        more).
	 */
	public BackendInfo
		(String name,
		 int totalCpus,
		 State state,
		 long stateTime,
		 String host,
		 String jvm,
		 String classpath,
		 String[] jvmflags)
		{
		this.name = name;
		this.totalCpus = totalCpus;
		this.state = state;
		this.stateTime = stateTime;
		this.host = host;
		this.jvm = jvm;
		this.classpath = classpath;
		this.jvmflags = jvmflags;
		}

	}