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* 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
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package org.apache.cayenne.access;
import java.util.List;
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.graph.GraphChangeHandler;
import org.apache.cayenne.map.ObjEntity;
import org.apache.cayenne.query.ObjectIdQuery;
import org.apache.cayenne.query.Query;
import org.apache.cayenne.reflect.AttributeProperty;
import org.apache.cayenne.reflect.ClassDescriptor;
import org.apache.cayenne.reflect.Property;
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 DataContext.
* Graph node ids are expected to be ObjectIds.
*
* @since 1.2
* @author Andrus Adamchik
*/
class ChildDiffLoader implements GraphChangeHandler {
ObjectContext context;
ChildDiffLoader(ObjectContext context) {
this.context = context;
}
public void nodeIdChanged(Object nodeId, Object newId) {
throw new CayenneRuntimeException("Not supported");
}
public void nodeCreated(Object nodeId) {
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);
}
public void nodeRemoved(Object nodeId) {
context.deleteObject(findObject(nodeId));
}
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());
try {
descriptor.getProperty(property).writeProperty(object, null, newValue);
}
catch (Exception e) {
throw new CayenneRuntimeException("Error setting property: " + property, e);
}
}
public void arcCreated(Object nodeId, Object targetNodeId, Object arcId) {
final Persistent source = findObject(nodeId);
final Persistent target = findObject(targetNodeId);
ClassDescriptor descriptor = context.getEntityResolver().getClassDescriptor(
((ObjectId) nodeId).getEntityName());
Property property = descriptor.getProperty(arcId.toString());
property.visit(new PropertyVisitor() {
public boolean visitAttribute(AttributeProperty property) {
return false;
}
public boolean visitToMany(ToManyProperty property) {
property.addTarget(source, target, false);
return false;
}
public boolean visitToOne(ToOneProperty property) {
property.setTarget(source, target, false);
return false;
}
});
}
public void arcDeleted(Object nodeId, final Object targetNodeId, Object arcId) {
final Persistent source = findObject(nodeId);
ClassDescriptor descriptor = context.getEntityResolver().getClassDescriptor(
((ObjectId) nodeId).getEntityName());
Property property = descriptor.getProperty(arcId.toString());
property.visit(new PropertyVisitor() {
public boolean visitAttribute(AttributeProperty property) {
return false;
}
public boolean visitToMany(ToManyProperty property) {
Persistent target = findObject(targetNodeId);
property.removeTarget(source, target, false);
return false;
}
public boolean visitToOne(ToOneProperty property) {
property.setTarget(source, null, false);
return false;
}
});
}
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;
}
// 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);
}
}