ReplicatedMap.java
/*
* 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 org.apache.catalina.tribes.tipis;
import java.io.Serializable;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import org.apache.catalina.tribes.Channel;
import org.apache.catalina.tribes.ChannelException;
import org.apache.catalina.tribes.ChannelException.FaultyMember;
import org.apache.catalina.tribes.Member;
import org.apache.catalina.tribes.RemoteProcessException;
import org.apache.juli.logging.Log;
import org.apache.juli.logging.LogFactory;
/**
* All-to-all replication for a hash map implementation. Each node in the cluster will carry an identical
* copy of the map.<br><br>
* This map implementation doesn't have a background thread running to replicate changes.
* If you do have changes without invoking put/remove then you need to invoke one of the following methods:
* <ul>
* <li><code>replicate(Object,boolean)</code> - replicates only the object that belongs to the key</li>
* <li><code>replicate(boolean)</code> - Scans the entire map for changes and replicates data</li>
* </ul>
* the <code>boolean</code> value in the <code>replicate</code> method used to decide
* whether to only replicate objects that implement the <code>ReplicatedMapEntry</code> interface
* or to replicate all objects. If an object doesn't implement the <code>ReplicatedMapEntry</code> interface
* each time the object gets replicated the entire object gets serialized, hence a call to <code>replicate(true)</code>
* will replicate all objects in this map that are using this node as primary.
*
* <br><br><b>REMEMBER TO CALL <code>breakdown()</code>
* when you are done with the map to avoid memory leaks.</b><br><br>
* TODO implement periodic sync/transfer thread<br>
* TODO memberDisappeared, should do nothing except change map membership
* by default it relocates the primary objects
*
* @param <K> The type of Key
* @param <V> The type of Value
*/
public class ReplicatedMap<K,V> extends AbstractReplicatedMap<K,V> {
private static final long serialVersionUID = 1L;
// Lazy init to support serialization
private transient volatile Log log;
//--------------------------------------------------------------------------
// CONSTRUCTORS / DESTRUCTORS
//--------------------------------------------------------------------------
/**
* Creates a new map
* @param owner The map owner
* @param channel The channel to use for communication
* @param timeout long - timeout for RPC messages
* @param mapContextName String - unique name for this map, to allow multiple maps per channel
* @param initialCapacity int - the size of this map, see HashMap
* @param loadFactor float - load factor, see HashMap
* @param cls Class loaders
*/
public ReplicatedMap(MapOwner owner, Channel channel, long timeout, String mapContextName, int initialCapacity,float loadFactor, ClassLoader[] cls) {
super(owner,channel, timeout, mapContextName, initialCapacity, loadFactor, Channel.SEND_OPTIONS_DEFAULT, cls, true);
}
/**
* Creates a new map
* @param owner The map owner
* @param channel The channel to use for communication
* @param timeout long - timeout for RPC messages
* @param mapContextName String - unique name for this map, to allow multiple maps per channel
* @param initialCapacity int - the size of this map, see HashMap
* @param cls Class loaders
*/
public ReplicatedMap(MapOwner owner, Channel channel, long timeout, String mapContextName, int initialCapacity, ClassLoader[] cls) {
super(owner,channel, timeout, mapContextName, initialCapacity, DEFAULT_LOAD_FACTOR,
Channel.SEND_OPTIONS_DEFAULT, cls, true);
}
/**
* Creates a new map
* @param owner The map owner
* @param channel The channel to use for communication
* @param timeout long - timeout for RPC messages
* @param mapContextName String - unique name for this map, to allow multiple maps per channel
* @param cls Class loaders
*/
public ReplicatedMap(MapOwner owner, Channel channel, long timeout, String mapContextName, ClassLoader[] cls) {
super(owner, channel, timeout, mapContextName, DEFAULT_INITIAL_CAPACITY, DEFAULT_LOAD_FACTOR,
Channel.SEND_OPTIONS_DEFAULT, cls, true);
}
/**
* Creates a new map
* @param owner The map owner
* @param channel The channel to use for communication
* @param timeout long - timeout for RPC messages
* @param mapContextName String - unique name for this map, to allow multiple maps per channel
* @param cls Class loaders
* @param terminate boolean - Flag for whether to terminate this map that failed to start.
*/
public ReplicatedMap(MapOwner owner, Channel channel, long timeout, String mapContextName, ClassLoader[] cls, boolean terminate) {
super(owner, channel, timeout, mapContextName, DEFAULT_INITIAL_CAPACITY, DEFAULT_LOAD_FACTOR,
Channel.SEND_OPTIONS_DEFAULT, cls, terminate);
}
//------------------------------------------------------------------------------
// METHODS TO OVERRIDE
//------------------------------------------------------------------------------
@Override
protected int getStateMessageType() {
return AbstractReplicatedMap.MapMessage.MSG_STATE_COPY;
}
@Override
protected int getReplicateMessageType() {
return AbstractReplicatedMap.MapMessage.MSG_COPY;
}
@Override
protected Member[] publishEntryInfo(Object key, Object value) throws ChannelException {
if (! (key instanceof Serializable && value instanceof Serializable) ) {
return new Member[0];
}
//select a backup node
Member[] backup = getMapMembers();
if (backup == null || backup.length == 0) {
return null;
}
try {
//publish the data out to all nodes
MapMessage msg = new MapMessage(getMapContextName(), MapMessage.MSG_COPY, false,
(Serializable) key, (Serializable) value, null,channel.getLocalMember(false), backup);
getChannel().send(backup, msg, getChannelSendOptions());
} catch (ChannelException e) {
FaultyMember[] faultyMembers = e.getFaultyMembers();
if (faultyMembers.length == 0) {
throw e;
}
List<Member> faulty = new ArrayList<>();
for (FaultyMember faultyMember : faultyMembers) {
if (!(faultyMember.getCause() instanceof RemoteProcessException)) {
faulty.add(faultyMember.getMember());
}
}
Member[] realFaultyMembers = faulty.toArray(new Member[0]);
if (realFaultyMembers.length != 0) {
backup = excludeFromSet(realFaultyMembers, backup);
if (backup.length == 0) {
throw e;
} else {
if (getLog().isWarnEnabled()) {
getLog().warn(sm.getString("replicatedMap.unableReplicate.completely", key,
Arrays.toString(backup), Arrays.toString(realFaultyMembers)), e);
}
}
}
}
return backup;
}
@Override
public void memberDisappeared(Member member) {
boolean removed = false;
Log log = getLog();
synchronized (mapMembers) {
removed = (mapMembers.remove(member) != null );
if (!removed) {
if (log.isDebugEnabled()) {
log.debug(sm.getString("replicatedMap.member.disappeared.unknown", member));
}
return; //the member was not part of our map.
}
}
if (log.isInfoEnabled()) {
log.info(sm.getString("replicatedMap.member.disappeared", member));
}
long start = System.currentTimeMillis();
for (Entry<K, MapEntry<K, V>> e : innerMap.entrySet()) {
MapEntry<K,V> entry = innerMap.get(e.getKey());
if (entry==null) {
continue;
}
if (entry.isPrimary()) {
try {
Member[] backup = getMapMembers();
if (backup.length > 0) {
MapMessage msg = new MapMessage(getMapContextName(), MapMessage.MSG_NOTIFY_MAPMEMBER,false,
(Serializable)entry.getKey(),null,null,channel.getLocalMember(false),backup);
getChannel().send(backup, msg, getChannelSendOptions());
}
entry.setBackupNodes(backup);
entry.setPrimary(channel.getLocalMember(false));
} catch (ChannelException x) {
log.error(sm.getString("replicatedMap.unable.relocate", entry.getKey()), x);
}
} else if (member.equals(entry.getPrimary())) {
entry.setPrimary(null);
}
if ( entry.getPrimary() == null &&
entry.isCopy() &&
entry.getBackupNodes()!=null &&
entry.getBackupNodes().length > 0 &&
entry.getBackupNodes()[0].equals(channel.getLocalMember(false)) ) {
try {
entry.setPrimary(channel.getLocalMember(false));
entry.setBackup(false);
entry.setProxy(false);
entry.setCopy(false);
Member[] backup = getMapMembers();
if (backup.length > 0) {
MapMessage msg = new MapMessage(getMapContextName(), MapMessage.MSG_NOTIFY_MAPMEMBER,false,
(Serializable)entry.getKey(),null,null,channel.getLocalMember(false),backup);
getChannel().send(backup, msg, getChannelSendOptions());
}
entry.setBackupNodes(backup);
if ( mapOwner!=null ) {
mapOwner.objectMadePrimary(entry.getKey(),entry.getValue());
}
} catch (ChannelException x) {
log.error(sm.getString("replicatedMap.unable.relocate", entry.getKey()), x);
}
}
} //while
long complete = System.currentTimeMillis() - start;
if (log.isInfoEnabled()) {
log.info(sm.getString("replicatedMap.relocate.complete",
Long.toString(complete)));
}
}
@Override
public void mapMemberAdded(Member member) {
if ( member.equals(getChannel().getLocalMember(false)) ) {
return;
}
boolean memberAdded = false;
synchronized (mapMembers) {
if (!mapMembers.containsKey(member) ) {
mapMembers.put(member, Long.valueOf(System.currentTimeMillis()));
memberAdded = true;
}
}
if ( memberAdded ) {
synchronized (stateMutex) {
Member[] backup = getMapMembers();
for (Entry<K, MapEntry<K, V>> e : innerMap.entrySet()) {
MapEntry<K,V> entry = innerMap.get(e.getKey());
if ( entry == null ) {
continue;
}
if (entry.isPrimary() && !inSet(member,entry.getBackupNodes())) {
entry.setBackupNodes(backup);
}
}
}
}
}
private Log getLog() {
if (log == null) {
synchronized (this) {
if (log == null) {
log = LogFactory.getLog(ReplicatedMap.class);
}
}
}
return log;
}
}