com.vaadin.addon.jpacontainer.BatchableEntityProvider Maven / Gradle / Ivy
/*
* JPAContainer
* Copyright (C) 2010 Oy IT Mill Ltd
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see
* If the entites handled by this provider contain complex associations, special
* care should be taken to enforce data integrity. The following example
* scenarios might give unexpected results if not dealt with properly:
*
* Example 1
*
* - Add Entity1
* - Add Entity2
* - Update Entity1 to reference Entity2
* - Run batch
*
* Depending on the entity manager implementation and cascading settings, this
* might cause an exception due to a nonexistent reference to Entity2 at step 1,
* or a duplicate of Entity2 at step 2.
*
* Example 2
*
* - Add Entity1
* - Add Entity2
* - Update Entity1 to reference Entity2
* - Remove Entity2
* - Run batch
*
* First of all, Entity2 should not be added at all as it is added and removed
* inside the same transaction. However, there is still a reference to Entity2
* from Entity1. If cascading is turned on, this might result in both Entity1
* and Entity2 being added nonetheless.
*
* @see JPAContainer#setWriteThrough(boolean)
* @see JPAContainer#isWriteThrough()
* @author Petter Holmström (IT Mill)
* @since 1.0
*/
public interface BatchableEntityProvider extends MutableEntityProvider {
/**
* Callback interface used by the
* {@link BatchableEntityProvider#batchUpdate(com.vaadin.addon.jpacontainer.BatchableEntityProvider.BatchUpdateCallback) }
* method.
*
* @author Petter Holmström (IT Mill)
* @since 1.0
*/
public static interface BatchUpdateCallback extends Serializable {
/**
* Runs the updates using a special batch enabled mutable entity
* provider.
*
* @param batchEnabledEntityProvider
* a {@link MutableEntityProvider} that knows how to handle
* multiple updates and executes them within a single
* transaction.
*/
public void batchUpdate(
MutableEntityProvider batchEnabledEntityProvider);
}
/**
* Executes a batch update using the specified callback parameter. The batch
* update should be run inside a single transaction. The implementation may
* either handle the transaction itself, or rely on external transaction handling
* provided by a container such as Spring or EJB. If the batch update
* fails, the entire transaction should be rolled back and an exception
* thrown. Otherwise, it should be committed.
*
* Clients should instantiate {@link BatchUpdateCallback}, implement the
* {@link BatchUpdateCallback#batchUpdate(MutableEntityProvider) } method and
* execute the updates as if they were using an ordinary
* {@link MutableEntityProvider}. The following example saves a list of
* transient entities:
*
* provider.batchUpdate(new BatchUpdateCallback() {
* public void batchUpdate(MutableEntityProvider batchEnabledEntityProvider) {
* for (Entity e : myListOfEntitiesToAdd) {
* batchEnabledEntityProvider.addEntity(e);
* }
* }
* });
*
*
* @param callback
* the callback that will be used to run the batch update.
* @throws UnsupportedOperationException
* if this entity provider does not support batch updates.
*/
public void batchUpdate(BatchUpdateCallback callback)
throws UnsupportedOperationException;
}