net.sf.ehcache.distribution
Class MulticastRMICacheManagerPeerProvider

java.lang.Object
  net.sf.ehcache.distribution.RMICacheManagerPeerProvider
      net.sf.ehcache.distribution.MulticastRMICacheManagerPeerProvider

All Implemented Interfaces:

CacheManagerPeerProvider

public final class MulticastRMICacheManagerPeerProvider
extends RMICacheManagerPeerProvider
implements CacheManagerPeerProvider

A peer provider which discovers peers using Multicast.

Hosts can be in three different levels of conformance with the Multicast specification (RFC1112), according to the requirements they meet.

1. Level 0 is the "no support for IP Multicasting" level. Lots of hosts and routers in the Internet are in this state, as multicast support is not mandatory in IPv4 (it is, however, in IPv6). Not too much explanation is needed here: hosts in this level can neither send nor receive multicast packets. They must ignore the ones sent by other multicast capable hosts.
2. Level 1 is the "support for sending but not receiving multicast IP datagrams" level. Thus, note that it is not necessary to join a multicast group to be able to send datagrams to it. Very few additions are needed in the IP module to make a "Level 0" host "Level 1-compliant".
3. Level 2 is the "full support for IP multicasting" level. Level 2 hosts must be able to both send and receive multicast traffic. They must know the way to join and leave multicast groups and to propagate this information to multicast routers. Thus, they must include an Internet Group Management Protocol (IGMP) implementation in their TCP/IP stack.

The list of CachePeers is maintained via heartbeats. rmiUrls are looked up using RMI and converted to CachePeers on registration. On lookup any stale references are removed.

Version:

$Id: MulticastRMICacheManagerPeerProvider.java 52 2006-04-24 14:50:03Z gregluck $

Author:

Greg Luck

Nested Class Summary

protected static class

MulticastRMICacheManagerPeerProvider.CachePeerEntry Entry containing a looked up CachePeer and date

Field Summary

static int

STALE_PEER_TIME_MS The number of ms until the peer is considered to be offline.

Fields inherited from class net.sf.ehcache.distribution.RMICacheManagerPeerProvider

peerUrls

Constructor Summary

MulticastRMICacheManagerPeerProvider(CacheManager cacheManager, java.net.InetAddress groupMulticastAddress, java.lang.Integer groupMulticastPort)
Creates and starts a multicast peer provider

Method Summary

void	dispose() Shutdown the heartbeat
void	init() Notifies providers to initialise themselves.
java.util.List	listRemoteCachePeers(Cache cache)
void	registerPeer(java.lang.String rmiUrl) Register a new peer.
protected boolean	stale(java.util.Date date) Whether the entry should be considered stale.

Methods inherited from class net.sf.ehcache.distribution.RMICacheManagerPeerProvider

extractCacheName, getCacheManager, lookupRemoteCachePeer, unregisterPeer

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface net.sf.ehcache.distribution.CacheManagerPeerProvider

unregisterPeer

Field Detail

STALE_PEER_TIME_MS

public static final int STALE_PEER_TIME_MS

The number of ms until the peer is considered to be offline. Once offline it will not be sent notifications.

See Also:

Constant Field Values

Constructor Detail

MulticastRMICacheManagerPeerProvider

public MulticastRMICacheManagerPeerProvider(CacheManager cacheManager,
                                            java.net.InetAddress groupMulticastAddress,
                                            java.lang.Integer groupMulticastPort)

Creates and starts a multicast peer provider

Parameters:

groupMulticastAddress - 224.0.0.1 to 239.255.255.255 e.g. 230.0.0.1

groupMulticastPort - 1025 to 65536 e.g. 4446

Method Detail

init

public final void init()
                throws CacheException

Notifies providers to initialise themselves.

Specified by:

init in interface CacheManagerPeerProvider

Specified by:

init in class RMICacheManagerPeerProvider

Throws:

CacheException

registerPeer

public final void registerPeer(java.lang.String rmiUrl)

Register a new peer.

Specified by:

registerPeer in interface CacheManagerPeerProvider

Specified by:

registerPeer in class RMICacheManagerPeerProvider

Parameters:

rmiUrl -

listRemoteCachePeers

public final java.util.List listRemoteCachePeers(Cache cache)
                                          throws CacheException

Specified by:

listRemoteCachePeers in interface CacheManagerPeerProvider

Specified by:

listRemoteCachePeers in class RMICacheManagerPeerProvider

Returns:

a list of CachePeer peers, excluding the local peer.

Throws:

CacheException

dispose

public final void dispose()

Shutdown the heartbeat

Specified by:

dispose in interface CacheManagerPeerProvider

Overrides:

dispose in class RMICacheManagerPeerProvider

stale

protected final boolean stale(java.util.Date date)

Whether the entry should be considered stale. This will depend on the type of RMICacheManagerPeerProvider. This method should be overridden for implementations that go stale based on date

Specified by:

stale in class RMICacheManagerPeerProvider

Parameters:

date - the date the entry was created

Returns:

true if stale