Provides the abstraction of a java.util.Hashtable that is replicated at several locations. Any change to the hashtable (clear, put, remove etc) will transparently be propagated to all replicas in the group. All read-only methods will always access the local replica.
Both keys and values added to the hashtable must be serializable, the reason being that they will be sent across the network to all replicas of the group. Having said this, it is now for example possible to add RMI remote objects to the hashtable as they are derived from java.rmi.server.RemoteObject
which in turn is serializable. This allows to lookup shared distributed objects by their name and invoke methods on them, regardless of one's onw location. A DistributedHashtable
thus allows to implement a distributed naming service in just a couple of lines.
An instance of this class will contact an existing member of the group to fetch its initial state (using the state exchange funclet StateExchangeFunclet
.
@author Bela Ban
@author Alfonso Olias-Sanz
@version $Id: DistributedHashtable.java,v 1.26 2006/09/01 14:40:26 belaban Exp $