/* * JBoss, Home of Professional Open Source. * Copyright 2009, Red Hat Middleware LLC, and individual contributors * as indicated by the @author tags. See the copyright.txt file in the * distribution for a full listing of individual contributors. * * This is free software; you can redistribute it and/or modify it * under the terms of the GNU Lesser General Public License as * published by the Free Software Foundation; either version 2.1 of * the License, or (at your option) any later version. * * This software 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 * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this software; if not, write to the Free * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA * 02110-1301 USA, or see the FSF site: http://www.fsf.org. */ package org.jboss.ha.timestamp; import org.jboss.ha.framework.interfaces.ClusterNode; /** * An object that observes changes in a {@link TimestampDiscrepancyService}. * * @author Brian Stansberry * * @version $Revision: $ */ public interface TimestampDiscrepancyObserver { /** * Notification from {@link TimestampDiscrepancyService} when it has * changed the {@link TimestampDiscrepancy} associated with a particular * node. * * @param node the node * @param discrepancy the new discrepancy */ void timestampDiscrepancyChanged(ClusterNode node, TimestampDiscrepancy discrepancy); /** * Callback allowing the observer to veto the removal by the * {@link TimestampDiscrepancyService} of discrepancy data for a * node that is no longer active in the cluster. Allows the observer to * request that data for historically relevant nodes be retained. * * @param dead the node * @param lastChecked the time (in ms since the epoch) the caller was * last able to obtain timestamp information from the * caller * * @return <code>true</code> if the data can be removed, <code>false</code> * if it must be retained. */ boolean canRemoveDeadEntry(ClusterNode dead, long lastChecked); }