com.j_spaces.core
Interface LeaseContext

All Superinterfaces:

Lease

All Known Implementing Classes:

LeaseProxy

public interface LeaseContext
extends Lease

LeaseContext is a return-value encapsulation of a write operation.

Using either IJSpace.write(Object, net.jini.core.transaction.Transaction, long) or IJSpace.write(Object, net.jini.core.transaction.Transaction, long, long, int) with the Modifiers.UPDATE_OR_WRITE returns a LeaseContext according to UPDATE-OR-WRITE semantics. The update-or-write operation is atomic - either a write or an update is performed.

LeaseContext's getObject() returns:

• null � on a successful write
• previous value � on successful update

 //first write
 LeaseContext lease = space.write((Object)o, null, 1000);
 lease.getUID(); //returns UID of written object
 lease.getOriginalObject(); //returns null on first write
 lease.renew(Lease.FOREVER);
 
 //second write - equivalent to update
 lease = space.write((Object)o, null, 1000);
 lease.getUID(); //returns UID of object
 lease.getOriginalObject(); //returns previous value (i.e. of previous write)
 try{
   lease.renew(Lease.FOREVER); 
 }catch(UnsupportedOperationException e) {
  //not a real lease - constructed by update.
 }
 
  

Field Summary

Fields inherited from interface net.jini.core.lease.Lease

ABSOLUTE, ANY, DURATION, FOREVER

Method Summary

Object	getObject() returns the previous value associated with this update-or-write operation.
String	getUID() Returns UID of written Entry.

Methods inherited from interface net.jini.core.lease.Lease

canBatch, cancel, createLeaseMap, getExpiration, getSerialFormat, renew, setSerialFormat

Method Detail

getObject

Object getObject()

returns the previous value associated with this update-or-write operation.

• null � on a successful write
• previous value � on successful update

Returns:

the associated object.

getUID

String getUID()

Returns UID of written Entry.

Returns:

UID of written Entry.