/*

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * particular file as subject to the "Classpath" exception as provided

 *

 * This code 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

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 */

package com.sun.corba.se.impl.activation;

import java.util.*;

import com.sun.corba.se.impl.orbutil.ORBConstants;

/** ProcessMonitorThread is started when ServerManager is instantiated. The

  * thread wakes up every minute (This can be changed by setting sleepTime) and

  * makes sure that all the processes (Servers) registered with the ServerTool

  * are healthy. If not the state in ServerTableEntry will be changed to

  * De-Activated.

  * Note: This thread can be killed from the main thread by calling

  *       interrupThread()

  */

public class ProcessMonitorThread extends java.lang.Thread {

    private HashMap serverTable;

    private int sleepTime;

    private static ProcessMonitorThread instance = null;

    private ProcessMonitorThread( HashMap ServerTable, int SleepTime ) {

        serverTable = ServerTable;

        sleepTime = SleepTime;

    }

    public void run( ) {

        while( true ) {

            try {

                // Sleep's for a specified time, before checking

                // the Servers health. This will repeat as long as

                // the ServerManager (ORBD) is up and running.

                Thread.sleep( sleepTime );

            } catch( java.lang.InterruptedException e ) {

                break;

            }

            Iterator serverList;

            synchronized ( serverTable ) {

                // Check each ServerTableEntry to make sure that they

                // are in the right state.

                serverList = serverTable.values().iterator();

            }

            try {

                checkServerHealth( serverList );

            } catch( ConcurrentModificationException e ) {

                break;

            }

        }

    }

    private void checkServerHealth( Iterator serverList ) {

        if( serverList == null ) return;

        while (serverList.hasNext( ) ) {

            ServerTableEntry entry = (ServerTableEntry) serverList.next();

            entry.checkProcessHealth( );

        }

    }

    static void start( HashMap serverTable ) {

        int sleepTime = ORBConstants.DEFAULT_SERVER_POLLING_TIME;

        String pollingTime = System.getProperties().getProperty(

            ORBConstants.SERVER_POLLING_TIME );

        if ( pollingTime != null ) {

            try {

                sleepTime = Integer.parseInt( pollingTime );

            } catch (Exception e ) {

                // Too late to complain, Just use the default

                // sleepTime

            }

        }

        instance = new ProcessMonitorThread( serverTable,

            sleepTime );

        instance.setDaemon( true );

        instance.start();

    }

    static void interruptThread( ) {

        instance.interrupt();

    }

}