com.sun.jdo.api.persistence.support

Class SynchronizationManager

java.lang.Object

com.sun.jdo.api.persistence.support.SynchronizationManager

All Implemented Interfaces:

Synchronization

public class SynchronizationManager
extends Object
implements Synchronization

This class allows for multiple instances to be called at transaction completion, which JDO does not currently provide. JDO only provides for a single instance to be registered. This service exploits the JDO capability by registering an instance of SynchronizationManager with JDO and then calling each instance registered with itself.

Version:

1.0

Author:

Craig Russell

Field Summary

Fields

Modifier and Type	Field and Description
protected static int	defaultCapacity The default capacity of the List of Synchronizations.
protected List	synchronizations The list of instances to synchronize.

Constructor Summary

Constructors

Modifier	Constructor and Description
	SynchronizationManager() Creates new SynchronizationManager instance with a default capacity of the List of Synchronization instances.
	SynchronizationManager(int initialCapacity) Creates new SynchronizationManager instance specifying the initial capacity of the list of Synchronization instances.
protected	SynchronizationManager(PersistenceManager pm) Creates new SynchronizationManager instance and registers it with the persistence manager.

Method Summary

Methods

Modifier and Type	Method and Description
void	afterCompletion(int status) This method will be called during transaction completion.
void	beforeCompletion() This method will be called during transaction completion.
protected static SynchronizationManager	getSynchronizationManager(PersistenceManager pm) Get the synchronization manager already registered with this persistence manager.
protected void	registerSynchronization(Synchronization instance) Register an instance with this synchronization manager.
static void	registerSynchronization(Synchronization instance, PersistenceManager pm) Register a new Synchronization with the current transaction.
static void	setDefaultCapacity(int capacity) Specify the default capacity of the list of Synchronizations.

Methods inherited from class java.lang.Object

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

Field Detail

defaultCapacity

protected static int defaultCapacity

The default capacity of the List of Synchronizations.

synchronizations

protected final List synchronizations

The list of instances to synchronize. Duplicate registrations will result in the instance being called multiple times. Since we cannot depend on the caller implementing hashCode and equals, we cannot use a Set implementaion.

Constructor Detail

SynchronizationManager

public SynchronizationManager(int initialCapacity)

Creates new SynchronizationManager instance specifying the initial capacity of the list of Synchronization instances.

Parameters:

initialCapacity - the initial capacity of the List of Synchronization instances

SynchronizationManager

public SynchronizationManager()

Creates new SynchronizationManager instance with a default capacity of the List of Synchronization instances.

SynchronizationManager

protected SynchronizationManager(PersistenceManager pm)

Creates new SynchronizationManager instance and registers it with the persistence manager.

Parameters:

pm - the persistence manager managing this transaction

Method Detail

registerSynchronization

public static void registerSynchronization(Synchronization instance,
                           PersistenceManager pm)

Register a new Synchronization with the current transaction.

Parameters:

instance - the instance to be registered

pm - the persistence manager which manages this transaction

setDefaultCapacity

public static void setDefaultCapacity(int capacity)

Specify the default capacity of the list of Synchronizations.

Parameters:

capacity - the default capacity of the List of Synchronizations

getSynchronizationManager

protected static SynchronizationManager getSynchronizationManager(PersistenceManager pm)

Get the synchronization manager already registered with this persistence manager. If the synchronization instance is not of the proper class, then replace it with a new instance of the synchronization manager, and register the previous synchronization with the newly created synchronization manager.

Parameters:

pm - the persistence manager

Returns:

the synchronization manager

beforeCompletion

public void beforeCompletion()

This method will be called during transaction completion. Resource access is allowed. This method in turn calls each registered instance beforeCompletion method.

Specified by:

beforeCompletion in interface Synchronization

afterCompletion

public void afterCompletion(int status)

This method will be called during transaction completion. No resource access is allowed. This method in turn calls each registered instance afterCompletion method. After this method completes, instances must register again in the new transaction, but the synchronization manager remains bound to the persistence manager transaction instance.

Specified by:

afterCompletion in interface Synchronization

Parameters:

status - the completion status of the transaction

registerSynchronization

protected void registerSynchronization(Synchronization instance)

Register an instance with this synchronization manager. Note that this is not thread-safe. If multiple threads call this method at the same time, the synchronizations List might become corrupt. The correct way to fix this is to ask the PersistenceManager for the Multithreaded flag and perform a synchronized add if the flag is true. We currently do not have the Multithreaded flag implemented.

Parameters:

instance - the instance to be registered