Package com.j_spaces.core

Interface LeaseContext<T>

All Superinterfaces:
Lease
All Known Implementing Classes:
LeaseInitializer.UIDLease, LeaseInitializer.UpdateContextLease, LeaseProxy, SpaceEntryLease
public interface LeaseContext<T> extends Lease
LeaseContext is a return-value encapsulation of a write operation.

Using either IPojoSpace.write(Object, net.jini.core.transaction.Transaction, long) or IPojoSpace.write(Object, net.jini.core.transaction.Transaction, long, long, int) with the UpdateModifiers.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.
 }
Version:
5.0
Author:
Lior Ben Yizhak

  • Method Details

    • getUID

      String getUID()
      Returns UID of written Entry.
      Returns:
      UID of written Entry.

    • getVersion

      int getVersion()
      Returns the version of written \ updated entry.
      Returns:
      version of written \ updated entry.
      Since:
      9.0.0

    • getObject

      T getObject()
      returns the previous value associated with this update-or-write operation.
      • null, on a successful write
    • previous value, on successful update (Only if WriteModifiers.RETURN_PREV_ON_UPDATE is used, otherwise null)
      • Returns:
      the associated object.