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/* DGCImpl.java --

   Copyright (c) 1996, 1997, 1998, 1999, 2002, 2005

   Free Software Foundation, Inc.

This file is part of GNU Classpath.

GNU Classpath 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 2, or (at your option)

any later version.

GNU Classpath 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.

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

along with GNU Classpath; see the file COPYING.  If not, write to the

Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA

02110-1301 USA.

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. */

package gnu.java.rmi.dgc;

import gnu.java.rmi.server.UnicastServerRef;

import java.rmi.RemoteException;

import java.rmi.dgc.DGC;

import java.rmi.dgc.Lease;

import java.rmi.dgc.VMID;

import java.rmi.server.ObjID;

import java.rmi.server.RMISocketFactory;

import java.util.Hashtable;

/**

  * I let DGCImpl to extend UnicastServerRef, but not

  * UnicastRemoteObject, because UnicastRemoteObject must

  * exportObject automatically.

  */

public class DGCImpl

    extends UnicastServerRef implements DGC {

    private static final long LEASE_VALUE = 600000L;

    // leaseCache caches a LeaseRecord associated with a vmid

    private Hashtable leaseCache = new Hashtable();

public DGCImpl() throws RemoteException {

        super(new ObjID(ObjID.DGC_ID), 0, RMISocketFactory.getSocketFactory());

}

public Lease dirty(ObjID[] ids, long sequenceNum, Lease lease) throws RemoteException {

        VMID vmid = lease.getVMID();

        if (vmid == null)

            vmid = new VMID();

        long leaseValue = LEASE_VALUE;

        //long leaseValue = lease.getValue();

    lease = new Lease(vmid, leaseValue);

        synchronized(leaseCache){

            LeaseRecord lr = (LeaseRecord)leaseCache.get(vmid);

            if (lr != null)

                lr.reset(leaseValue);

            else{

                lr = new LeaseRecord(vmid, leaseValue);

                leaseCache.put(vmid, lr);

            }

        }

        return (lease);

}

public void clean(ObjID[] ids, long sequenceNum, VMID vmid, boolean strong) throws RemoteException {

  // Not implemented

}

  /**

   * LeaseRecord associates a vmid to expireTime.

   */

  private static class LeaseRecord{

    private VMID vmid;

    private long expireTime;

    LeaseRecord(VMID vmid, long leaseValue){

      this.vmid = vmid;

      reset(leaseValue);

    }

    // reset expireTime

    void reset(long leaseValue){

      long l = System.currentTimeMillis();

      expireTime = l + leaseValue;

    }

    boolean isExpired(){

      long l = System.currentTimeMillis();

      if ( l > expireTime)

        return true;

      return false;

    }

  } //End of LeaseRecord

} //End of DGCImpl