com.sleepycat.je.rep.StateChangeEvent Maven / Gradle / Ivy
/*-
* Copyright (C) 2002, 2018, Oracle and/or its affiliates. All rights reserved.
*
* This file was distributed by Oracle as part of a version of Oracle Berkeley
* DB Java Edition made available at:
*
* http://www.oracle.com/technetwork/database/database-technologies/berkeleydb/downloads/index.html
*
* Please see the LICENSE file included in the top-level directory of the
* appropriate version of Oracle Berkeley DB Java Edition for a copy of the
* license and additional information.
*/
package com.sleepycat.je.rep;
import java.io.Serializable;
import com.sleepycat.je.rep.ReplicatedEnvironment.State;
import com.sleepycat.je.rep.impl.node.NameIdPair;
/**
* Communicates the {@link ReplicatedEnvironment.State state} change at a node
* to the StateChangeListener. There is a distinct instance of this event
* representing each state change at a node.
*
* Each event instance may have zero or more state change related exceptions
* associated with it. The exceptions are of type {@link StateChangeException}.
* {@link StateChangeException} has a method called {@link
* StateChangeException#getEvent()} that can be used to associate an event with
* an exception.
* @see StateChangeListener
*/
public class StateChangeEvent implements Serializable {
private static final long serialVersionUID = 1L;
final private ReplicatedEnvironment.State state;
final private NameIdPair masterNameId;
/* Records the time associated with the event. */
final private long eventTime = System.currentTimeMillis();
/**
* @hidden
* For internal use only.
* Creates a StateChangeEvent identifying the new state and the new master
* if there is a master in the new state.
*
* @param state the new state
* @param masterNameId the new master or NULL if there isn't
* one.
*/
public StateChangeEvent(State state, NameIdPair masterNameId) {
assert((masterNameId.getId() == NameIdPair.NULL_NODE_ID) ||
((state == State.MASTER) || (state == State.REPLICA))):
"state=" + state + " masterId=" + masterNameId.getId();
this.state = state;
this.masterNameId = masterNameId;
}
/**
* Returns the state that the node has transitioned to.
*
* @return the new State resulting from this event
*/
public ReplicatedEnvironment.State getState() {
return state;
}
/**
* Returns the time (in nano second units) the event occurred, as reported
* by {@link System#nanoTime}
*
* @return the time the event occurred, in nanoseconds
*/
public long getEventTime() {
return eventTime;
}
/**
* Returns the node name identifying the master at the time of the event.
*
* @return the master node name
*
* @throws IllegalStateException if the node is in the
* DETACHED or UNKNOWN state.
*/
public String getMasterNodeName()
throws IllegalStateException {
if ((state == State.MASTER) || (state == State.REPLICA)) {
return masterNameId.getName();
}
throw new IllegalStateException("No current master in state: " +
state);
}
}