wt.method
Class ClusterMonitor

java.lang.Object
  java.rmi.server.RemoteObject
      java.rmi.server.RemoteServer
          wt.util.RMIServer
              wt.cache.CacheManager
                  wt.method.ClusterMonitor

All Implemented Interfaces:

CacheServer, Remote, RemoteAccess, Serializable, Unreferenced

public class ClusterMonitor

extends CacheManager

implements RemoteAccess

ClusterMonitor extends CacheManager to maintain a collection of live references to other ClusterMonitor objects in the cluster. An instance of ClusterMonitor is created at method server startup using the wt.method.loadObject mechanism. At startup, each instance of ClusterMonitor adds itself to its master's cache. In this way, all instances of ClusterMonitor and thus all MethodServers, and ServerManagers become known to the Cache Master. The cache of ClusterMonitors can be queried to return a Vector of live references to all ClusterMonitors. (Dead references are removed prior to return) All MethodServerInfo and ServerManagerInfo objects in the cluster can be collected with a single method call for performance monitoring. This provides a mechanism for displaying cluster state and performance metrics. Loaded by MethodServerMain via property wt.method.loadObjects

See Also:

Serialized Form

Field Summary

static String	ALL_SERVERS_KEY
private static Cache	cache
private static int	CACHE_SIZE
private static ClusterMonitor	clusterMonitor
static String	SERVER_INFO_KEY
private static boolean	VERBOSE

Fields inherited from class wt.cache.CacheManager

MASTER

Fields inherited from class wt.util.RMIServer

csf, ssf

Fields inherited from class java.rmi.server.RemoteServer

Fields inherited from class java.rmi.server.RemoteObject

ref

Fields inherited from interface wt.method.RemoteAccess

versionID

Fields inherited from interface wt.cache.CacheServer

versionID

Constructor Summary

ClusterMonitor()

Method Summary

static HashMap	getAllInfos()
static Vector	getAllServers()
static RemoteStub	getClusterMonitorStub() Return the RemoteStub to this ClusterMonitor
int	getDefaultSize() Get desired size of this cache.
Object	getEntry(Object key) Override CacheManager's getEntry When key is of CacheServer return that server's MethodServerInfo or ServerManagerInfo object When key is ALL_SERVERS_KEY request Vector from the Master Cache
Object	getInfo()
private static boolean	isAlive(RemoteStub stub)
static void	main(String[] args)
void	ping() Remote method for verifying ccess.
void	putEntry(Object key, Object value) Override CacheManager's putEntry
static RemoteStub	Registrar(Boolean register_flag) Allow a remote client to register/unregister this ClusterMonitor from the CacheManager.
void	removeEntry(Object key) Protected method which allows subclasses of CacheManager to take some action when a entry is being removed from the local cache.
void	reset() Method called when connection to master cache is broken and recovered indicating that a notification from another project cache might have been missed.

Methods inherited from class wt.cache.CacheManager

checkAccess, get, getDefaultName, isCacheHost, overflow, put, putEntry, reference, registerSlave, remove, remove, removeEntry, unreferenced, update, updateEntry, updateEntry

Methods inherited from class wt.util.RMIServer

clone, exportObject, exportObject, exportObject, getClientSocketFactory, getPort, getServerSocketFactory, getStub, isHostInList, isLocalHost, setPort, writeReplace

Methods inherited from class java.rmi.server.RemoteServer

getClientHost, getLog, setLog

Methods inherited from class java.rmi.server.RemoteObject

equals, getRef, hashCode, toString, toStub

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

clusterMonitor

private static ClusterMonitor clusterMonitor

VERBOSE

private static final boolean VERBOSE

cache

private static Cache cache

ALL_SERVERS_KEY

public static final String ALL_SERVERS_KEY

See Also:

Constant Field Values

SERVER_INFO_KEY

public static final String SERVER_INFO_KEY

See Also:

Constant Field Values

CACHE_SIZE

private static final int CACHE_SIZE

Constructor Detail

ClusterMonitor

public ClusterMonitor()
               throws RemoteException

Method Detail

putEntry

public void putEntry(Object key,
                     Object value)

Override CacheManager's putEntry

Overrides:

putEntry in class CacheManager

Parameters:

key - the key object

value - the value object

getEntry

public Object getEntry(Object key)

Override CacheManager's getEntry When key is of CacheServer return that server's MethodServerInfo or ServerManagerInfo object When key is ALL_SERVERS_KEY request Vector from the Master Cache

Specified by:

getEntry in interface CacheServer

Overrides:

getEntry in class CacheManager

removeEntry

public void removeEntry(Object key)

Description copied from class: CacheManager

Protected method which allows subclasses of CacheManager to take some action when a entry is being removed from the local cache. This method is invoked to remove the entry in the local cache as a result of a local remove call or a call forwarded from a master cache. If this cache has a master cache, the remove call will already be forwarded to the master before this method is invoked. Slave caches will be notified to remove their entries after this method returns. This method must not cause a recursive remove call.

This method is not called when entries are being removed by the overflow or reset methods.

Supported API: true

Overrides:

removeEntry in class CacheManager

Parameters:

key - the key object (null = clear entire cache)

reset

public void reset()
           throws RemoteException

Method called when connection to master cache is broken and recovered indicating that a notification from another project cache might have been missed. The local cache is cleared and the ClusterMontor is re-registered.

Overrides:

reset in class CacheManager

Throws:

RemoteException

ping

public void ping()

Description copied from class: CacheManager

Remote method for verifying ccess.

Supported API: false

Specified by:

ping in interface CacheServer

Overrides:

ping in class CacheManager

getDefaultSize

public int getDefaultSize()

Description copied from class: CacheManager

Get desired size of this cache. This method attemps to find a size property called wt.cache.size.CacheName where cacheName is the name of this cache. Subclasses can override this method to control cache size in some other way. If no property is found, the default size is 100.

Supported API: true

Overrides:

getDefaultSize in class CacheManager

getInfo

public Object getInfo()

isAlive

private static boolean isAlive(RemoteStub stub)

getAllInfos

public static HashMap getAllInfos()

getAllServers

public static Vector getAllServers()

getClusterMonitorStub

public static RemoteStub getClusterMonitorStub()

Return the RemoteStub to this ClusterMonitor

Registrar

public static RemoteStub Registrar(Boolean register_flag)

Allow a remote client to register/unregister this ClusterMonitor from the CacheManager. Provides a mechanism to test & verify Cache configuration

main

public static void main(String[] args)