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* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
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package org.apache.cayenne;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;
import java.util.List;
import org.apache.cayenne.access.jdbc.CollectionResultIterator;
import org.apache.cayenne.event.EventManager;
import org.apache.cayenne.graph.CompoundDiff;
import org.apache.cayenne.graph.GraphDiff;
import org.apache.cayenne.graph.GraphManager;
import org.apache.cayenne.map.ObjEntity;
import org.apache.cayenne.query.Query;
import org.apache.cayenne.reflect.ClassDescriptor;
import org.apache.cayenne.util.EventUtil;
import org.apache.cayenne.validation.ValidationException;
import org.apache.cayenne.validation.ValidationResult;
/**
* A default generic implementation of ObjectContext suitable for accessing
* Cayenne from either an ORM or a client tiers. Communicates with Cayenne via a
* {@link org.apache.cayenne.DataChannel}.
*
* @since 1.2
*/
public class CayenneContext extends BaseContext {
CayenneContextGraphManager graphManager;
// object that merges "backdoor" changes that come from the channel.
CayenneContextMergeHandler mergeHandler;
/**
* Creates a new CayenneContext with no channel and disabled graph events.
*/
public CayenneContext() {
this(null);
}
/**
* Creates a new CayenneContext, initializing it with a channel instance.
* CayenneContext created using this constructor WILL NOT broadcast graph
* change events.
*/
public CayenneContext(DataChannel channel) {
this(channel, false, false);
}
/**
* Creates a new CayenneContext, initializing it with a channel.
*/
public CayenneContext(DataChannel channel, boolean changeEventsEnabled, boolean lifecyleEventsEnabled) {
graphManager = new CayenneContextGraphManager(this, changeEventsEnabled, lifecyleEventsEnabled);
if (channel != null) {
attachToChannel(channel);
}
}
/**
* @since 3.1
*/
@Override
protected void attachToChannel(DataChannel channel) {
super.attachToChannel(channel);
if (mergeHandler != null) {
mergeHandler.active = false;
mergeHandler = null;
}
EventManager eventManager = channel.getEventManager();
if (eventManager != null) {
mergeHandler = new CayenneContextMergeHandler(this);
// listen to our channel events...
// note that we must reset listener on channel switch, as there is
// no
// guarantee that a new channel uses the same EventManager.
EventUtil.listenForChannelEvents(channel, mergeHandler);
}
}
/**
* Returns true if this context posts individual object modification events.
* Subject used for these events is
* <code>ObjectContext.GRAPH_CHANGED_SUBJECT</code>.
*/
public boolean isChangeEventsEnabled() {
return graphManager.changeEventsEnabled;
}
/**
* Returns true if this context posts lifecycle events. Subjects used for
* these events are
* <code>ObjectContext.GRAPH_COMMIT_STARTED_SUBJECT, ObjectContext.GRAPH_COMMITTED_SUBJECT,
* ObjectContext.GRAPH_COMMIT_ABORTED_SUBJECT, ObjectContext.GRAPH_ROLLEDBACK_SUBJECT.</code>
* .
*/
public boolean isLifecycleEventsEnabled() {
return graphManager.lifecycleEventsEnabled;
}
@Override
public GraphManager getGraphManager() {
return graphManager;
}
CayenneContextGraphManager internalGraphManager() {
return graphManager;
}
/**
* Commits changes to uncommitted objects. First checks if there are changes
* in this context and if any changes are detected, sends a commit message
* to remote Cayenne service via an internal instance of CayenneConnector.
*/
@Override
public void commitChanges() {
doCommitChanges(true);
}
GraphDiff doCommitChanges(boolean cascade) {
int syncType = cascade ? DataChannel.FLUSH_CASCADE_SYNC : DataChannel.FLUSH_NOCASCADE_SYNC;
GraphDiff commitDiff = null;
synchronized (graphManager) {
if (graphManager.hasChanges()) {
if (isValidatingObjectsOnCommit()) {
ValidationResult result = new ValidationResult();
Iterator<?> it = graphManager.dirtyNodes().iterator();
while (it.hasNext()) {
Persistent p = (Persistent) it.next();
if (p instanceof Validating) {
switch (p.getPersistenceState()) {
case PersistenceState.NEW:
((Validating) p).validateForInsert(result);
break;
case PersistenceState.MODIFIED:
((Validating) p).validateForUpdate(result);
break;
case PersistenceState.DELETED:
((Validating) p).validateForDelete(result);
break;
}
}
}
if (result.hasFailures()) {
throw new ValidationException(result);
}
}
graphManager.graphCommitStarted();
GraphDiff changes = graphManager.getDiffsSinceLastFlush();
try {
commitDiff = channel.onSync(this, changes, syncType);
} catch (Throwable th) {
graphManager.graphCommitAborted();
if (th instanceof CayenneRuntimeException) {
throw (CayenneRuntimeException) th;
} else {
throw new CayenneRuntimeException("Commit error", th);
}
}
graphManager.graphCommitted(commitDiff);
// this event is caught by peer nested ObjectContexts to
// synchronize the
// state
fireDataChannelCommitted(this, changes);
}
}
return commitDiff;
}
@Override
public void commitChangesToParent() {
doCommitChanges(false);
}
@Override
public void rollbackChanges() {
synchronized (graphManager) {
if (graphManager.hasChanges()) {
GraphDiff diff = graphManager.getDiffs();
graphManager.graphReverted();
channel.onSync(this, diff, DataChannel.ROLLBACK_CASCADE_SYNC);
fireDataChannelRolledback(this, diff);
}
}
}
@Override
public void rollbackChangesLocally() {
synchronized (graphManager) {
if (graphManager.hasChanges()) {
GraphDiff diff = graphManager.getDiffs();
graphManager.graphReverted();
fireDataChannelRolledback(this, diff);
}
}
}
/**
* Creates and registers a new Persistent object instance.
*/
@Override
public <T> T newObject(Class<T> persistentClass) {
if (persistentClass == null) {
throw new NullPointerException("Persistent class can't be null.");
}
ObjEntity entity = getEntityResolver().getObjEntity(persistentClass);
if (entity == null) {
throw new CayenneRuntimeException("No entity mapped for class: " + persistentClass);
}
ClassDescriptor descriptor = getEntityResolver().getClassDescriptor(entity.getName());
T object = (T) descriptor.createObject();
descriptor.injectValueHolders(object);
registerNewObject((Persistent) object, entity.getName(), descriptor);
return object;
}
/**
* @since 3.0
*/
@Override
public void registerNewObject(Object object) {
if (object == null) {
throw new NullPointerException("An attempt to register null object.");
}
ObjEntity entity = getEntityResolver().getObjEntity(object.getClass());
ClassDescriptor descriptor = getEntityResolver().getClassDescriptor(entity.getName());
registerNewObject((Persistent) object, entity.getName(), descriptor);
}
/**
* Runs a query, returning result as list.
*/
@Override
public List performQuery(Query query) {
List result = onQuery(this, query).firstList();
return result != null ? result : new ArrayList<Object>(1);
}
@Override
public QueryResponse performGenericQuery(Query query) {
return onQuery(this, query);
}
public QueryResponse onQuery(ObjectContext context, Query query) {
return new CayenneContextQueryAction(this, context, query).execute();
}
@Override
public Collection<?> uncommittedObjects() {
synchronized (graphManager) {
return graphManager.dirtyNodes();
}
}
@Override
public Collection<?> deletedObjects() {
synchronized (graphManager) {
return graphManager.dirtyNodes(PersistenceState.DELETED);
}
}
@Override
public Collection<?> modifiedObjects() {
synchronized (graphManager) {
return graphManager.dirtyNodes(PersistenceState.MODIFIED);
}
}
@Override
public Collection<?> newObjects() {
synchronized (graphManager) {
return graphManager.dirtyNodes(PersistenceState.NEW);
}
}
// ****** non-public methods ******
void registerNewObject(Persistent object, String entityName, ClassDescriptor descriptor) {
/**
* We should create new id only if it is not set for this object. It
* could have been created, for instance, in child context
*/
ObjectId id = object.getObjectId();
if (id == null) {
id = new ObjectId(entityName);
object.setObjectId(id);
}
injectInitialValue(object);
}
Persistent createFault(ObjectId id) {
ClassDescriptor descriptor = getEntityResolver().getClassDescriptor(id.getEntityName());
Persistent object;
synchronized (graphManager) {
object = (Persistent) descriptor.createObject();
object.setPersistenceState(PersistenceState.HOLLOW);
object.setObjectContext(this);
object.setObjectId(id);
graphManager.registerNode(id, object);
}
return object;
}
@Override
protected GraphDiff onContextFlush(ObjectContext originatingContext, GraphDiff changes, boolean cascade) {
boolean childContext = this != originatingContext && changes != null;
if (childContext) {
// PropertyChangeProcessingStrategy oldStrategy =
// getPropertyChangeProcessingStrategy();
// setPropertyChangeProcessingStrategy(PropertyChangeProcessingStrategy.RECORD);
try {
changes.apply(new CayenneContextChildDiffLoader(this));
} finally {
// setPropertyChangeProcessingStrategy(oldStrategy);
}
fireDataChannelChanged(originatingContext, changes);
}
return (cascade) ? doCommitChanges(true) : new CompoundDiff();
}
/**
* Returns <code>true</code> if there are any modified, deleted or new
* objects registered with this CayenneContext, <code>false</code>
* otherwise.
*/
public boolean hasChanges() {
return graphManager.hasChanges();
}
/**
* This method simply returns an iterator over a list of selected objects.
* There's no performance benefit of using it vs. regular "select".
*
* @since 3.2
*/
public <T> ResultIterator<T> iterator(org.apache.cayenne.query.Select<T> query) {
List<T> objects = select(query);
return new CollectionResultIterator<T>(objects);
}
}