Author: fhanik
Date: Fri Mar 10 17:35:20 2006
New Revision: 384984
URL: http://svn.apache.org/viewcvs?rev=384984&view=rev
Log:
started to document the replicated map.
Modified:
tomcat/container/tc5.5.x/modules/groupcom/src/share/org/apache/catalina/tribes/tipis/LazyReplicatedMap.java
tomcat/container/tc5.5.x/modules/groupcom/test/org/apache/catalina/tribes/demos/MapDemo.java
Modified:
tomcat/container/tc5.5.x/modules/groupcom/src/share/org/apache/catalina/tribes/tipis/LazyReplicatedMap.java
URL:
http://svn.apache.org/viewcvs/tomcat/container/tc5.5.x/modules/groupcom/src/share/org/apache/catalina/tribes/tipis/LazyReplicatedMap.java?rev=384984&r1=384983&r2=384984&view=diff
==============================================================================
---
tomcat/container/tc5.5.x/modules/groupcom/src/share/org/apache/catalina/tribes/tipis/LazyReplicatedMap.java
(original)
+++
tomcat/container/tc5.5.x/modules/groupcom/src/share/org/apache/catalina/tribes/tipis/LazyReplicatedMap.java
Fri Mar 10 17:35:20 2006
@@ -25,6 +25,7 @@
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
+import java.util.Collections;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.LinkedHashSet;
@@ -41,19 +42,48 @@
import org.apache.catalina.tribes.mcast.McastMember;
/**
- * @todo implement periodic sync/transfer
+ * A smart implementation of a stateful replicated map. uses primary/secondary
backup strategy.
+ * One node is always the primary and one node is always the backup.
+ * This map is synchronized across a cluster, and only has one backup
member.<br/>
+ * A perfect usage for this map would be a session map for a session manager
in a clustered environment.<br/>
+ * The only way to modify this list is to use the <code>put, putAll,
remove</code> methods.
+ * entrySet, entrySetFull, keySet, keySetFull, returns all non modifiable
sets.<br><br>
+ * If objects (values) in the map change without invoking <code>put()</code>
or <code>remove()</code>
+ * the data can be distributed using two different methods:<br>
+ * <code>replicate(boolean)</code> and <code>replicate(Object,
boolean)</code><br>
+ * These two methods are very important two understand. The map can work with
two set of value objects:<br>
+ * 1. Serializable - the entire object gets serialized each time it is
replicated<br>
+ * 2. ReplicatedMapEntry - this interface allows for a isDirty() flag and to
replicate diffs if desired.<br>
+ * Implementing the <code>ReplicatedMapEntry</code> interface allows you to
decide what objects
+ * get replicated and how much data gets replicated each time.<br>
+ * If you implement a smart AOP mechanism to detect changes in underlying
objects, you can replicate
+ * only those changes by implementing the ReplicatedMapEntry interface, and
return true when isDiffable()
+ * is invoked.<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.
+ *
+ * @todo implement periodic sync/transfer thread
* @author Filip Hanik
* @version 1.0
*/
public class LazyReplicatedMap extends LinkedHashMap
implements RpcCallback, ChannelListener, MembershipListener {
protected static org.apache.commons.logging.Log log =
org.apache.commons.logging.LogFactory.getLog(LazyReplicatedMap.class);
- protected static long TIME_OUT = 15000;//hard coded timeout
//------------------------------------------------------------------------------
// INSTANCE VARIABLES
//------------------------------------------------------------------------------
-
+ private transient long rpcTimeout = 5000;
private transient Channel channel;
private transient RpcChannel rpcChannel;
private transient byte[] mapContextName;
@@ -64,24 +94,25 @@
//------------------------------------------------------------------------------
// CONSTRUCTORS / DESTRUCTORS
//------------------------------------------------------------------------------
- public LazyReplicatedMap(Channel channel, String mapContextName, int
initialCapacity, float loadFactor) {
+ public LazyReplicatedMap(Channel channel, long timeout, String
mapContextName, int initialCapacity, float loadFactor) {
super(initialCapacity,loadFactor);
- init(channel,mapContextName);
+ init(channel,mapContextName,timeout);
}
- public LazyReplicatedMap(Channel channel, String mapContextName, int
initialCapacity) {
+ public LazyReplicatedMap(Channel channel, long timeout, String
mapContextName, int initialCapacity) {
super(initialCapacity);
- init(channel,mapContextName);
+ init(channel,mapContextName, timeout);
}
- public LazyReplicatedMap(Channel channel, String mapContextName) {
+ public LazyReplicatedMap(Channel channel, long timeout, String
mapContextName) {
super();
- init(channel,mapContextName);
+ init(channel,mapContextName,timeout);
}
- void init(Channel channel, String mapContextName) {
+ void init(Channel channel, String mapContextName, long timeout) {
final String chset = "ISO-8859-1";
this.channel = channel;
+ this.rpcTimeout = timeout;
try {
this.mapContextName = mapContextName.getBytes(chset);
}catch (UnsupportedEncodingException x) {
@@ -92,7 +123,6 @@
this.channel.addChannelListener(this);
this.channel.addMembershipListener(this);
transferState();
-
}
public void breakDown() {
@@ -179,7 +209,7 @@
if ( backup != null ) {
MapMessage msg = new
MapMessage(mapContextName,MapMessage.MSG_STATE,false,
null,null,null,null);
- Response[] resp = rpcChannel.send(new Member[]
{backup},msg,rpcChannel.FIRST_REPLY,TIME_OUT);
+ Response[] resp = rpcChannel.send(new Member[]
{backup},msg,rpcChannel.FIRST_REPLY,rpcTimeout);
if ( resp.length > 0 ) {
msg = (MapMessage)resp[0].getMessage();
ArrayList list = (ArrayList)msg.getValue();
@@ -398,7 +428,7 @@
MapMessage msg = new MapMessage(mapContextName,
MapMessage.MSG_RETRIEVE_BACKUP, false,
(Serializable) key, null,
null, null);
Response[] resp = rpcChannel.send(new Member[]
{entry.getBackupNode()},
- msg,
this.rpcChannel.FIRST_REPLY, TIME_OUT);
+ msg,
this.rpcChannel.FIRST_REPLY, rpcTimeout);
if (resp == null || resp.length == 0) {
//no responses
log.warn("Unable to retrieve object for key:" + key);
@@ -517,7 +547,7 @@
MapEntry entry = (MapEntry)e.getValue();
if ( entry.isPrimary() ) set.add(entry.getValue());
}
- return set;
+ return Collections.unmodifiableSet(set);
}
public Set keySet() {
@@ -530,7 +560,7 @@
MapEntry entry = (MapEntry)e.getValue();
if ( entry.isPrimary() ) set.add(entry.getKey());
}
- return set;
+ return Collections.unmodifiableSet(set);
}
public int sizeFull() {
@@ -566,7 +596,7 @@
MapEntry entry = (MapEntry)e.getValue();
if ( entry.isPrimary() ) values.add(entry.getValue());
}
- return values;
+ return Collections.unmodifiableCollection(values);
}
Modified:
tomcat/container/tc5.5.x/modules/groupcom/test/org/apache/catalina/tribes/demos/MapDemo.java
URL:
http://svn.apache.org/viewcvs/tomcat/container/tc5.5.x/modules/groupcom/test/org/apache/catalina/tribes/demos/MapDemo.java?rev=384984&r1=384983&r2=384984&view=diff
==============================================================================
---
tomcat/container/tc5.5.x/modules/groupcom/test/org/apache/catalina/tribes/demos/MapDemo.java
(original)
+++
tomcat/container/tc5.5.x/modules/groupcom/test/org/apache/catalina/tribes/demos/MapDemo.java
Fri Mar 10 17:35:20 2006
@@ -54,7 +54,7 @@
protected SimpleTableDemo table;
public MapDemo(Channel channel ) {
- map = new LazyReplicatedMap(channel,"MapDemo");
+ map = new LazyReplicatedMap(channel,5000, "MapDemo");
table =
SimpleTableDemo.createAndShowGUI(map,channel.getLocalMember().getName());
channel.addChannelListener(this);
channel.addMembershipListener(this);
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