/* ********************************************************************** **
** Copyright notice **
** **
** (c) 2005-2009 RSSOwl Development Team **
** http://www.rssowl.org/ **
** **
** All rights reserved **
** **
** This program and the accompanying materials are made available under **
** the terms of the Eclipse Public License v1.0 which accompanies this **
** distribution, and is available at: **
** http://www.rssowl.org/legal/epl-v10.html **
** **
** A copy is found in the file epl-v10.html and important notices to the **
** license from the team is found in the textfile LICENSE.txt distributed **
** in this package. **
** **
** This copyright notice MUST APPEAR in all copies of the file! **
** **
** Contributors: **
** RSSOwl Development Team - initial API and implementation **
** **
** ********************************************************************** */
package org.rssowl.core.internal.persist.dao;
import org.eclipse.core.runtime.Assert;
import org.eclipse.core.runtime.SafeRunner;
import org.rssowl.core.internal.persist.service.DBHelper;
import org.rssowl.core.persist.IEntity;
import org.rssowl.core.persist.dao.IEntityDAO;
import org.rssowl.core.persist.event.EntityListener;
import org.rssowl.core.persist.event.ModelEvent;
import org.rssowl.core.persist.event.runnable.EventType;
import org.rssowl.core.persist.service.PersistenceException;
import org.rssowl.core.util.LoggingSafeRunnable;
import com.db4o.ext.Db4oException;
import com.db4o.query.Query;
import java.util.List;
import java.util.Set;
import java.util.concurrent.CopyOnWriteArrayList;
/**
* A db4o abstract implementation of EntityDAO.
*
* @param <T> Type of concrete implementation of IEntity.
* @param <L> Type of EntityListener.
* @param <E> Type of ModelEvent.
*/
public abstract class AbstractEntityDAO<T extends IEntity, L extends EntityListener<E, T>, E extends ModelEvent> extends AbstractPersistableDAO<T> implements IEntityDAO<T, L, E> {
/** The List of Listeners for this DAO */
protected final List<L> fEntityListeners = new CopyOnWriteArrayList<L>();
/**
* Creates an instance of this class.
*
* @param entityClass
* @param saveFully
*/
public AbstractEntityDAO(Class<? extends T> entityClass, boolean saveFully) {
super(entityClass, saveFully);
}
/**
* @param entity the entity the is saved.
* @return the model event for the entity.
*/
protected abstract E createSaveEventTemplate(T entity);
/**
* @param entity the entity that is deleted.
* @return the model event for the entity.
*/
protected abstract E createDeleteEventTemplate(T entity);
/*
* @see org.rssowl.core.persist.dao.IEntityDAO#exists(long)
*/
public boolean exists(long id) {
try {
return !(loadList(id).isEmpty());
} catch (Db4oException e) {
throw new PersistenceException(e);
}
}
/*
* @see org.rssowl.core.model.internal.db4o.dao.PersistableDAO#load(long)
*/
public T load(long id) {
try {
List<T> list = loadList(id);
if (list.isEmpty())
return null;
if (list.size() > 1) {
String message = "There should only be a single entity for a given id, but there are: " + list.size() + ", id: " + id + ", entities:\n"; //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
for (T entity : list)
message += entity.toString() + "\n"; //$NON-NLS-1$
throw new IllegalStateException(message);
}
T entity = list.get(0);
// TODO Activate completely by default for now. Must decide how to deal with this.
fDb.activate(entity, Integer.MAX_VALUE);
return entity;
} catch (Db4oException e) {
throw new PersistenceException(e);
}
}
private List<T> loadList(long id) throws Db4oException {
Query query = fDb.query();
query.constrain(fEntityClass);
query.descend("fId").constrain(Long.valueOf(id)); //$NON-NLS-1$
return getList(query);
}
/*
* @see
* org.rssowl.core.internal.persist.dao.AbstractPersistableDAO#preSave(org
* .rssowl.core.persist.IPersistable)
*/
@Override
protected void preSave(T entity) {
E event = createSaveEventTemplate(entity);
if (event != null)
DBHelper.putEventTemplate(event);
}
/*
* @see
* org.rssowl.core.internal.persist.dao.AbstractPersistableDAO#preDelete(org
* .rssowl.core.persist.IPersistable)
*/
@Override
protected void preDelete(T entity) {
E event = createDeleteEventTemplate(entity);
if (event != null)
DBHelper.putEventTemplate(event);
}
/*
* @see org.rssowl.core.persist.dao.IEntityDAO#fireEvents(java.util.Set,
* org.rssowl.core.persist.event.runnable.EventType)
*/
public final void fireEvents(final Set<E> events, final EventType eventType) {
Assert.isNotNull(eventType, "eventType"); //$NON-NLS-1$
for (final L listener : fEntityListeners) {
SafeRunner.run(new LoggingSafeRunnable() {
public void run() throws Exception {
switch (eventType) {
case PERSIST:
listener.entitiesAdded(events);
break;
case UPDATE:
listener.entitiesUpdated(events);
break;
case REMOVE:
listener.entitiesDeleted(events);
break;
default:
throw new IllegalArgumentException("eventType unknown: " + eventType); //$NON-NLS-1$
}
}
});
}
}
/*
* @see
* org.rssowl.core.persist.dao.IEntityDAO#addEntityListener(org.rssowl.core
* .persist.event.EntityListener)
*/
public void addEntityListener(L listener) {
fEntityListeners.add(listener);
}
/*
* @see
* org.rssowl.core.persist.dao.IEntityDAO#removeEntityListener(org.rssowl.
* core.persist.event.EntityListener)
*/
public void removeEntityListener(L listener) {
fEntityListeners.remove(listener);
}
}