com.sun.jini.outrigger

Class MatchSetProxy

java.lang.Object

com.sun.jini.outrigger.MatchSetProxy

All Implemented Interfaces:

MatchSet

 class MatchSetProxy
extends Object
implements MatchSet

Outrigger's implementation of MatchSet. Outrigger's implementation of the JavaSpace05.contents method returns objects of this type. Created with an initial set of entries from the match set and supports pre-fetching whenever it needs additional entries. RemoteExceptions encountered when making a remote call to fetch the next batch of entries from the space generally do not invalidate the proxy or the match set.

Note, there is no way to serialize or otherwise copy instances of this class so the default equals implementation should suffice.

Field Summary

Fields

Modifier and Type	Field and Description
private int	i Current index into reps
private EntryRep	lastRepReturned Last rep returned
private Lease	lease Lease assocated with this query
private EntryRep[]	reps Last batch fetched from server
private OutriggerServer	space The remote server this proxy works with.
private boolean	unpackFailure True if reps[i] could not be unpacked
private Uuid	uuid ID of the associated query (and lease)

Constructor Summary

Constructors

Constructor and Description
MatchSetProxy(MatchSetData inital, SpaceProxy2 parent, OutriggerServer space)

Method Summary

Methods

Modifier and Type	Method and Description
Lease	getLease() Returns a proxy to the Lease associated with this match set, or null if this match set is not leased.
Entry	getSnapshot() Returns a snapshot of the Entry removed by the last call to next.
Entry	next() Removes one Entry from the match set and returns a copy to the caller.
String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

space

private final OutriggerServer space

The remote server this proxy works with.

uuid

private final Uuid uuid

ID of the associated query (and lease)

lease

private final Lease lease

Lease assocated with this query

reps

private EntryRep[] reps

Last batch fetched from server

lastRepReturned

private EntryRep lastRepReturned

Last rep returned

i

private int i

Current index into reps

unpackFailure

private boolean unpackFailure

True if reps[i] could not be unpacked

Constructor Detail

MatchSetProxy

MatchSetProxy(MatchSetData inital,
             SpaceProxy2 parent,
             OutriggerServer space)

Method Detail

getLease

public Lease getLease()

Description copied from interface: MatchSet

Returns a proxy to the Lease associated with this match set, or null if this match set is not leased.

Specified by:

getLease in interface MatchSet

Returns:

a proxy for the match set's lease, or null if there is no lease associated with this match set

next

public Entry next()
           throws RemoteException,
                  UnusableEntryException

Description copied from interface: MatchSet

Removes one Entry from the match set and returns a copy to the caller. Returns null if the match set is empty. The returned Entry must be unmarshalled in accordance with the Jini Entry Specification.

A given invocation of this method may perform remote communications, but generally the next method is not expected to have remote method constraints that can vary from invocation to invocation. Instead the set of constraints associated with the next method will be fixed at the time the match set was created, even if this object implements an interface like RemoteMethodControl that would otherwise allow the set of constraints associated with the next method to be altered.

Specified by:

next in interface MatchSet

Returns:

an Entry from the match set, or null if the match set is empty

Throws:

RemoteException - if a communication error occurs. If a RemoteException is thrown, no Entry was removed from the match set because of this call

UnusableEntryException - if the entry removed from the match set could not be unmarshalled

getSnapshot

public Entry getSnapshot()

Description copied from interface: MatchSet

Returns a snapshot of the Entry removed by the last call to next. Snapshots are defined in section JS.2.6 of the JavaSpaces Service Specification and are an alternative representation of a given Entry produced by a particular space for use with that same space. Passing a snapshot to a space is generally more efficient than passing the original representation.

Any snapshot returned by this method will meet the same contract as the object returned by passing the result of the last next invocation to JavaSpace.snapshot.

Generally there is a cost associated with calling the JavaSpace.snapshot method. Thus creating a snapshot using that method is usually only worthwhile if the resulting snapshot is used more than once. The cost of invoking this method should be low and should be worthwhile even if the resulting snapshot is used only once.

Specified by:

getSnapshot in interface MatchSet

Returns:

a snapshot of the Entry removed from the match set by the last call to next

toString

public String toString()

Overrides:

toString in class Object