src/main/java/com/sleepycat/je/rep/monitor/MonitorService.java

/*-
 * 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.monitor;

import static com.sleepycat.je.utilint.TestHookExecute.doHookIfSet;

import java.io.IOException;
import java.util.logging.Formatter;
import java.util.logging.Level;
import java.util.logging.Logger;

import com.sleepycat.je.rep.ReplicationGroup;
import com.sleepycat.je.rep.impl.TextProtocol.RequestMessage;
import com.sleepycat.je.rep.impl.TextProtocol.ResponseMessage;
import com.sleepycat.je.rep.monitor.Protocol.GroupChange;
import com.sleepycat.je.rep.monitor.Protocol.JoinGroup;
import com.sleepycat.je.rep.monitor.Protocol.LeaveGroup;
import com.sleepycat.je.rep.net.DataChannel;
import com.sleepycat.je.rep.utilint.ReplicationFormatter;
import com.sleepycat.je.rep.utilint.ServiceDispatcher;
import com.sleepycat.je.rep.utilint.ServiceDispatcher.ExecutingService;
import com.sleepycat.je.rep.utilint.ServiceDispatcher.ExecutingRunnable;
import com.sleepycat.je.utilint.LoggerUtils;
import com.sleepycat.je.utilint.TestHook;

/**
 * @hidden
 * For internal use only.
 */
public class MonitorService extends ExecutingService {

    /*
     * Test hooks that are run before processing various events.  If the hooks
     * throw IllegalStateException, then the event will not be processed.
     */
    public static volatile TestHook<GroupChangeEvent> processGroupChangeHook;
    public static volatile TestHook<JoinGroupEvent> processJoinGroupHook;
    public static volatile TestHook<LeaveGroupEvent> processLeaveGroupHook;

    private final Monitor monitor;
    private final Protocol protocol;
    private final Logger logger;
    private final Formatter formatter;

    /* Identifies the Group Service. */
    public static final String SERVICE_NAME = "Monitor";

    public MonitorService(Monitor monitor,
                          ServiceDispatcher dispatcher) {
        super(SERVICE_NAME, dispatcher);
        this.monitor = monitor;
        protocol = new Protocol(monitor.getGroupName(),
                                monitor.getMonitorNameIdPair(),
                                null,
                                dispatcher.getChannelFactory());
        logger = LoggerUtils.getLoggerFormatterNeeded(getClass());
        formatter = new ReplicationFormatter(monitor.getMonitorNameIdPair());
    }

    /* Dynamically invoked process methods */

    /**
     * Notify the monitor about the group change (add/remove a node) event.
     */
    public ResponseMessage process(GroupChange groupChange) {
        GroupChangeEvent event =
            new GroupChangeEvent(new ReplicationGroup(groupChange.getGroup()),
                                 groupChange.getNodeName(),
                                 groupChange.getOpType());
        try {
            assert doHookIfSet(processGroupChangeHook, event);
        } catch (IllegalStateException e) {
            return null;
        }
        monitor.notifyGroupChange(event);
        return null;
    }

    /**
     * Notify the monitor about a node has joined the group.
     */
    public ResponseMessage process(JoinGroup joinGroup) {
        JoinGroupEvent event = new JoinGroupEvent(joinGroup.getNodeName(),
                                                  joinGroup.getMasterName(),
                                                  joinGroup.getJoinTime());
        try {
            assert doHookIfSet(processJoinGroupHook, event);
        } catch (IllegalStateException e) {
            return null;
        }
        monitor.notifyJoin(event);
        return null;
    }

    /**
     * Notify the monitor about a node has left the group.
     */
    public ResponseMessage process(LeaveGroup leaveGroup) {
        LeaveGroupEvent event =
            new LeaveGroupEvent(leaveGroup.getNodeName(),
                                leaveGroup.getMasterName(),
                                leaveGroup.getLeaveReason(),
                                leaveGroup.getJoinTime(),
                                leaveGroup.getLeaveTime());
        try {
            assert doHookIfSet(processLeaveGroupHook, event);
        } catch (IllegalStateException e) {
            return null;
        }
        monitor.notifyLeave(event);
        return null;
    }

    @Override
    public Runnable getRunnable(DataChannel dataChannel) {
        return new MonitorServiceRunnable(dataChannel, protocol);
    }

    class MonitorServiceRunnable extends ExecutingRunnable {
        MonitorServiceRunnable(DataChannel dataChannel,
                               Protocol protocol) {
            super(dataChannel, protocol, false);
        }

        @Override
        protected ResponseMessage getResponse(RequestMessage request)
            throws IOException {

            return protocol.process(MonitorService.this, request);
        }

        @Override
        protected void logMessage(String message) {
            LoggerUtils.logMsg(logger, formatter, Level.WARNING, message);
        }
    }
}