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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
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*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
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* KIND, either express or implied. See the License for the
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package org.apache.cayenne.graph;
import java.util.Collection;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import org.apache.cayenne.CayenneRuntimeException;
import org.apache.cayenne.ObjectContext;
import org.apache.cayenne.ObjectId;
import org.apache.cayenne.Persistent;
import org.apache.cayenne.QueryResponse;
import org.apache.cayenne.map.ObjEntity;
import org.apache.cayenne.query.ObjectIdQuery;
import org.apache.cayenne.query.Query;
import org.apache.cayenne.reflect.ArcProperty;
import org.apache.cayenne.reflect.AttributeProperty;
import org.apache.cayenne.reflect.ClassDescriptor;
import org.apache.cayenne.reflect.PropertyDescriptor;
import org.apache.cayenne.reflect.PropertyVisitor;
import org.apache.cayenne.reflect.ToManyProperty;
import org.apache.cayenne.reflect.ToOneProperty;
/**
* A GraphChangeHandler that loads child ObjectContext diffs into a parent ObjectContext.
* Graph node ids are expected to be ObjectIds. This class is made public since 3.0 to be
* used in ObjectContext synchronizing
*
* @since 1.2
*/
public class ChildDiffLoader implements GraphChangeHandler {
// TODO: andrus 04/05/2009 - replace with PropertyChangeProcessingStrategy enum used
// in ROP?
static final ThreadLocal<Boolean> childDiffProcessing = new ThreadLocal<Boolean>() {
@Override
protected synchronized Boolean initialValue() {
return Boolean.FALSE;
}
};
protected ObjectContext context;
/**
* Returns whether child diff processing is in progress.
*
* @since 3.0
*/
public static boolean isProcessingChildDiff() {
return childDiffProcessing.get();
}
/**
* Sets whether child diff processing is in progress.
*
* @since 3.0
*/
public static void setExternalChange(Boolean flag) {
childDiffProcessing.set(flag);
}
public ChildDiffLoader(ObjectContext context) {
this.context = context;
}
public void nodeIdChanged(Object nodeId, Object newId) {
throw new CayenneRuntimeException("Not supported");
}
public void nodeCreated(Object nodeId) {
setExternalChange(Boolean.TRUE);
try {
ObjectId id = (ObjectId) nodeId;
if (id.getEntityName() == null) {
throw new NullPointerException("Null entity name in id " + id);
}
ObjEntity entity = context.getEntityResolver().getObjEntity(
id.getEntityName());
if (entity == null) {
throw new IllegalArgumentException("Entity not mapped with Cayenne: "
+ id);
}
Persistent dataObject = null;
try {
dataObject = (Persistent) entity.getJavaClass().newInstance();
}
catch (Exception ex) {
throw new CayenneRuntimeException("Error instantiating object.", ex);
}
dataObject.setObjectId(id);
context.registerNewObject(dataObject);
}
finally {
setExternalChange(Boolean.FALSE);
}
}
public void nodeRemoved(Object nodeId) {
setExternalChange(Boolean.TRUE);
Persistent object = findObject(nodeId);
if (object != null) {
try {
context.deleteObjects(object);
}
finally {
setExternalChange(Boolean.FALSE);
}
} else {
setExternalChange(Boolean.FALSE);
}
}
public void nodePropertyChanged(
Object nodeId,
String property,
Object oldValue,
Object newValue) {
// this change is for simple property, so no need to convert targets to server
// objects...
Persistent object = findObject(nodeId);
ClassDescriptor descriptor = context.getEntityResolver().getClassDescriptor(
((ObjectId) nodeId).getEntityName());
setExternalChange(Boolean.TRUE);
try {
descriptor.getProperty(property).writeProperty(object, oldValue, newValue);
}
catch (Exception e) {
throw new CayenneRuntimeException("Error setting property: " + property, e);
}
finally {
setExternalChange(Boolean.FALSE);
}
}
public void arcCreated(Object nodeId, Object targetNodeId, Object arcId) {
final Persistent source = findObject(nodeId);
final Persistent target = findObject(targetNodeId);
// if a target was later deleted, the diff for arcCreated is still preserved and
// can result in NULL target here.
if (target == null) {
return;
}
ClassDescriptor descriptor = context.getEntityResolver().getClassDescriptor(
((ObjectId) nodeId).getEntityName());
ArcProperty property = (ArcProperty) descriptor.getProperty(arcId.toString());
setExternalChange(Boolean.TRUE);
try {
property.visit(new PropertyVisitor() {
public boolean visitAttribute(AttributeProperty property) {
return false;
}
public boolean visitToMany(ToManyProperty property) {
// connect reverse arc if the relationship is marked as "runtime"
ArcProperty reverseArc = property.getComplimentaryReverseArc();
boolean autoConnectReverse = reverseArc != null
&& reverseArc.getRelationship().isRuntime();
property.addTarget(source, target, autoConnectReverse);
return false;
}
public boolean visitToOne(ToOneProperty property) {
property.setTarget(source, target, false);
return false;
}
});
}
finally {
setExternalChange(Boolean.FALSE);
}
}
public void arcDeleted(Object nodeId, final Object targetNodeId, Object arcId) {
final Persistent source = findObject(nodeId);
// needed as sometime temporary objects are evoked from the context before
// changing their relationships
if (source == null) {
return;
}
ClassDescriptor descriptor = context.getEntityResolver().getClassDescriptor(
((ObjectId) nodeId).getEntityName());
PropertyDescriptor property = descriptor.getProperty(arcId.toString());
setExternalChange(Boolean.TRUE);
try {
property.visit(new PropertyVisitor() {
public boolean visitAttribute(AttributeProperty property) {
return false;
}
public boolean visitToMany(ToManyProperty property) {
// connect reverse arc if the relationship is marked as "runtime"
ArcProperty reverseArc = property.getComplimentaryReverseArc();
boolean autoConnectReverse = reverseArc != null
&& reverseArc.getRelationship().isRuntime();
Persistent target = findObject(targetNodeId);
if (target == null) {
// this is usually the case when a NEW object was deleted and then
// its
// relationships were manipulated; so try to locate the object in
// the
// collection ...
// the performance of this is rather dubious of course...
target = findObjectInCollection(targetNodeId, property
.readProperty(source));
}
if (target == null) {
// ignore?
}
else {
property.removeTarget(source, target, autoConnectReverse);
}
return false;
}
public boolean visitToOne(ToOneProperty property) {
property.setTarget(source, null, false);
return false;
}
});
}
finally {
setExternalChange(Boolean.FALSE);
}
}
protected Persistent findObject(Object nodeId) {
// first do a lookup in ObjectStore; if even a hollow object is found, return it;
// if not - fetch.
Persistent object = (Persistent) context.getGraphManager().getNode(nodeId);
if (object != null) {
return object;
}
ObjectId id = (ObjectId) nodeId;
// this can happen if a NEW object is deleted and after that its relationships are
// modified
if (id.isTemporary()) {
return null;
}
// skip context cache lookup, go directly to its channel
Query query = new ObjectIdQuery((ObjectId) nodeId);
QueryResponse response = context.getChannel().onQuery(context, query);
List objects = response.firstList();
if (objects.size() == 0) {
throw new CayenneRuntimeException("No object for ID exists: " + nodeId);
}
else if (objects.size() > 1) {
throw new CayenneRuntimeException(
"Expected zero or one object, instead query matched: "
+ objects.size());
}
return (Persistent) objects.get(0);
}
protected Persistent findObjectInCollection(Object nodeId, Object toManyHolder) {
Collection c = (toManyHolder instanceof Map)
? ((Map) toManyHolder).values()
: (Collection) toManyHolder;
Iterator it = c.iterator();
while (it.hasNext()) {
Persistent o = (Persistent) it.next();
if (nodeId.equals(o.getObjectId())) {
return o;
}
}
return null;
}
}