net.jini.lease.LeaseRenewalEvent Maven / Gradle / Ivy
/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package net.jini.lease;
import java.io.IOException;
import java.util.EventObject;
import net.jini.core.lease.Lease;
import net.jini.core.lease.LeaseException;
import org.apache.river.api.io.AtomicSerial;
import org.apache.river.api.io.AtomicSerial.GetArg;
/**
* Event generated when a LeaseRenewalManager cannot renew
* a lease.
*
* The LeaseRenewalEvent instances are sent to the
* LeaseListener (if any) associated with a given lease
* when the lease was added to the managed set. These events are
* typically generated because one of the following conditions occur:
*
* - After successfully renewing a lease any number of times and
* experiencing no failures, the
LeaseRenewalManager
* determines, prior to the next renewal attempt, that the actual
* expiration time of the lease has passed, implying that any
* further attempt to renew the lease would be fruitless.
* - An indefinite exception occurs during each attempt to renew a
* lease, from the point that the first such exception occurs
* until the point when the
LeaseRenewalManager
* determines that lease's actual expiration time has passed.
* - A definite exception occurs during a lease renewal attempt.
*
*
* Note that bad object exceptions, bad invocation exceptions, and
* LeaseExceptions are all considered definite
* exceptions.
*
* This class encapsulates information about both the lease for which the
* failure occurred, as well as information about the condition that
* caused the renewal attempt to fail.
*
* This class is a subclass of the class EventObject,
* adding the following additional items of abstract state:
*
* - The lease on which the renewal attempt failed, and to which
* the event pertains
*
- The desired expiration time of the affected lease
*
- The
Throwable associated with the last renewal
* attempt (if any)
*
*
* In addition to the methods of the EventObject class,
* this class defines methods through which this additional state may be
* retrieved.
*
* The source associated with a LeaseRenewalEvent will be
* the LeaseRenewalManager that generated the event.
*
* @author Sun Microsystems, Inc.
* @see Lease
* @see LeaseException
* @see LeaseRenewalManager
* @see LeaseListener
* @see EventObject
*/
@AtomicSerial
public class LeaseRenewalEvent extends EventObject {
private static final long serialVersionUID = -626399341646348302L;
/**
* The failed lease.
*
* @serial
*/
private final Lease lease;
/**
* The desired expiration of the failed lease.
*
* @serial
*/
private final long expiration;
/**
* The exception that caused the failure, if any.
*
* @serial
*/
private final Throwable ex;
/**
* Constructs an instance of this class with the specified state.
*
* @param source reference to the instance of the
* LeaseRenewalManager that generated the event
* @param lease the lease to which the event pertains
* @param expiration the desired expiration time for the affected
* lease
* @param ex the Throwable associated with the last
* renewal attempt (if any)
* @see Lease
* @see LeaseRenewalManager
*/
public LeaseRenewalEvent(LeaseRenewalManager source,
Lease lease,
long expiration,
Throwable ex)
{
super(source);
this.lease = lease;
this.expiration = expiration;
this.ex = ex;
}
public LeaseRenewalEvent(GetArg arg) throws IOException, ClassNotFoundException{
this(null,
arg.get("lease", null, Lease.class),
arg.get("expiration", 0L),
arg.get("ex", null, Throwable.class)
);
}
/**
* Returns a reference to the lease to which the event pertains.
*
* @return the Lease object corresponding to the lease
* on which the renewal attempt failed
* @see Lease
*/
public Lease getLease() {
return lease;
}
/**
* Returns the desired expiration time of the lease to which event
* pertains.
*
* @return a long value that represents the desired
* expiration time of the lease on which the renewal attempt
* failed
*/
public long getExpiration() {
return expiration;
}
/**
* Returns the exception (if any) that caused the event to be sent.
* The conditions under which the event may be sent, and the related
* values returned by this method, are as follows:
*
*
* - When any lease in the managed set has passed its actual
* expiration time, and either the most recent renewal attempt
* was successful or there have been no renewal attempts, the
*
LeaseRenewalManager will cease any further
* attempts to renew the lease, and will send a
* LeaseRenewalEvent with no associated exception.
* In this case, invoking this method will return
* null.
* - For any lease from the managed set for which the most recent
* renewal attempt was unsuccessful because of the occurrence
* of a indefinite exception, the
*
LeaseRenewalManager will continue to attempt to
* renew the affected lease at the appropriate times until: the
* renewal succeeds, the lease's expiration time has passed, or
* a renewal attempt throws a definite exception. If a definite
* exception is thrown or the lease expires, the
* LeaseRenewalManager will cease any further
* attempts to renew the lease, and will send a
* LeaseRenewalEvent containing the exception
* associated with the last renewal attempt.
* - If, while attempting to renew a lease from the managed set,
* a definite exception is encountered, the
*
LeaseRenewalManager will cease any further
* attempts to renew the lease, and will send a
* LeaseRenewalEvent containing the particular
* exception that occurred.
*
*
* @return an instance of Throwable or
* null, indicating the condition that caused
* the LeaseRenewalManager to fail to renew the
* affected lease
*/
public Throwable getException() {
return ex;
}
}