org.vrspace.server
Class Transaction

java.lang.Object
  java.util.Observable
      org.vrspace.server.VRObject
          org.vrspace.server.DBObject
              org.vrspace.server.PassiveDBObject
                  org.vrspace.server.Transaction

All Implemented Interfaces:

java.lang.Cloneable, java.util.Observer

public class Transaction

extends PassiveDBObject

implements java.util.Observer

Transacton: collects request from a client. Caches all objects. Able of rollback, rollforward, isolation... PassiveDBObject: can be stored to database, cannot send nor receive network events.

Field Summary

static int	LAST_COMMITED
static int	LOCK_CLASS
static int	LOCK_OBJECT

Fields inherited from class org.vrspace.server.DBObject

db

Fields inherited from class org.vrspace.server.VRObject

db_id, primitiveMap, primitives

Constructor Summary

Transaction()

Method Summary

void	commit() Commit
void	rollback() Rollback a transaction.
void	rollforward() Rollforward - reply each request.
void	start(Client c) Start a transaction with LAST_COMMITED lock level (no locking)
void	start(Client c, int level) Start a transaciton.
void	update(java.util.Observable obs, java.lang.Object req) Process a request from client.

Methods inherited from class org.vrspace.server.PassiveDBObject

sendEvent

Methods inherited from class org.vrspace.server.DBObject

delete, get, put, put

Methods inherited from class org.vrspace.server.VRObject

arrayToString, canRead, canWrite, clone, equals, fieldToText, fromString, fromText, getClassName, getField, getFields, getId, getID, getMemebers, hasField, hasMethod, isNew, newInstance, sendResponse, setField, setField, setField, setFields, setFields, setValue, stringToArray, toString, toText, toText, toText

Methods inherited from class java.util.Observable

addObserver, clearChanged, countObservers, deleteObserver, deleteObservers, hasChanged, notifyObservers, notifyObservers, setChanged

Methods inherited from class java.lang.Object

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

Field Detail

LAST_COMMITED

public static final int LAST_COMMITED

See Also:

Constant Field Values

LOCK_CLASS

public static final int LOCK_CLASS

See Also:

Constant Field Values

LOCK_OBJECT

public static final int LOCK_OBJECT

See Also:

Constant Field Values

Constructor Detail

Transaction

public Transaction()

Method Detail

start

public void start(Client c)

Start a transaction with LAST_COMMITED lock level (no locking)

start

public void start(Client c,
                  int level)

Start a transaciton. Starts listening to all changes that client made.

Parameters:

level - LOCK_CLASS, LOCK_RECORD, LAST_COMMITED

update

public void update(java.util.Observable obs,
                   java.lang.Object req)

Process a request from client. Request is allready processed by Dispatcher and validated. Called by Client.
With LOCK_OBJECT or LOCK_CLASS isolation level, it means that object was not locked before.

Specified by:

update in interface java.util.Observer

commit

public void commit()

Commit

rollback

public void rollback()

Rollback a transaction. Calls VRObject.sendEvent() to set each field value, so rollback may be distributed.

rollforward

public void rollforward()

Rollforward - reply each request. Calls VRObject.sendEvent().
This does not lock or unlock objects or classes