rice.p2p.past
Class ContentHashPastContent

java.lang.Object
  rice.p2p.past.ContentHashPastContent

All Implemented Interfaces:

java.io.Serializable, PastContent

Direct Known Subclasses:

Delivery, DistPastTestContent, MyPastContent

public abstract class ContentHashPastContent

extends java.lang.Object

implements PastContent

Version:

$Id: ContentHashPastContent.java 2688 2005-08-03 01:45:34Z jstewart $

Author:

Peter Druschel, Alan Mislove

See Also:

Serialized Form

Field Summary

protected Id

myId

Constructor Summary

ContentHashPastContent(Id myId)

Method Summary

PastContent	checkInsert(Id id, PastContent existingContent) Checks if a insert operation should be allowed.
PastContentHandle	getHandle(Past local) Produces a handle for this content object.
Id	getId() Returns the Id under which this object is stored in Past.
boolean	isMutable() States if this content object is mutable.

Methods inherited from class java.lang.Object

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

Field Detail

myId

protected Id myId

Constructor Detail

ContentHashPastContent

public ContentHashPastContent(Id myId)

Method Detail

checkInsert

public PastContent checkInsert(Id id,
                               PastContent existingContent)
                        throws PastException

Checks if a insert operation should be allowed. Invoked when a Past node receives an insert request and it is a replica root for the id; invoked on the object to be inserted. This method determines the effect of an insert operation on an object that already exists: it computes the new value of the stored object, as a function of the new and the existing object.

Specified by:

checkInsert in interface PastContent

Parameters:

id - the key identifying the object

existingObj - the existing object stored on this node (null if no object associated with id is stored on this node)

Returns:

null, if the operation is not allowed; else, the new object to be stored on the local node.

Throws:

PastException

getHandle

public PastContentHandle getHandle(Past local)

Produces a handle for this content object. The handle is retrieved and returned to the client as a result of the Past.lookupHandles() method.

Specified by:

getHandle in interface PastContent

Parameters:

local - The local past service

Returns:

the handle

getId

public Id getId()

Returns the Id under which this object is stored in Past.

Specified by:

getId in interface PastContent

Returns:

the id

isMutable

public boolean isMutable()

States if this content object is mutable. Mutable objects are not subject to dynamic caching in Past.

Specified by:

isMutable in interface PastContent

Returns:

true if this object is mutable, else false