org.objectstyle.cayenne.util.ObjectContextQueryAction Maven / Gradle / Ivy
/* ====================================================================
*
* The ObjectStyle Group Software License, version 1.1
* ObjectStyle Group - http://objectstyle.org/
*
* Copyright (c) 2002-2005, Andrei (Andrus) Adamchik and individual authors
* of the software. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. The end-user documentation included with the redistribution, if any,
* must include the following acknowlegement:
* "This product includes software developed by independent contributors
* and hosted on ObjectStyle Group web site (http://objectstyle.org/)."
* Alternately, this acknowlegement may appear in the software itself,
* if and wherever such third-party acknowlegements normally appear.
*
* 4. The names "ObjectStyle Group" and "Cayenne" must not be used to endorse
* or promote products derived from this software without prior written
* permission. For written permission, email
* "andrus at objectstyle dot org".
*
* 5. Products derived from this software may not be called "ObjectStyle"
* or "Cayenne", nor may "ObjectStyle" or "Cayenne" appear in their
* names without prior written permission.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE OBJECTSTYLE GROUP OR
* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals and hosted on ObjectStyle Group web site. For more
* information on the ObjectStyle Group, please see
*
* Intended for internal use only.
*
*
* @since 1.2
* @author Andrus Adamchik
*/
public class ObjectContextQueryAction {
protected static final boolean DONE = true;
protected ObjectContext targetContext;
protected ObjectContext actingContext;
protected Query query;
protected QueryMetadata metadata;
protected transient QueryResponse response;
public ObjectContextQueryAction(ObjectContext actingContext,
ObjectContext targetContext, Query query) {
this.actingContext = actingContext;
this.query = query;
// no special target context and same target context as acting context mean the
// same thing. "normalize" the internal state to avoid confusion
this.targetContext = targetContext != actingContext ? targetContext : null;
this.metadata = query.getMetaData(actingContext.getEntityResolver());
}
/**
* Worker method that perfomrs internal query.
*/
public QueryResponse execute() {
if (interceptOIDQuery() != DONE) {
if (interceptRelationshipQuery() != DONE) {
runQuery();
}
}
interceptObjectConversion();
return response;
}
/**
* Transfers fetched objects into the target context if it is different from "acting"
* context. Note that when this method is invoked, result objects are already
* registered with acting context by the parent channel.
*/
protected void interceptObjectConversion() {
if (targetContext != null && !metadata.isFetchingDataRows()) {
// rewrite response to contain objects from the query context
GenericResponse childResponse = new GenericResponse();
for (response.reset(); response.next();) {
if (response.isList()) {
List objects = response.currentList();
if (objects.isEmpty()) {
childResponse.addResultList(objects);
}
else {
// TODO: Andrus 1/31/2006 - IncrementalFaultList is not properly
// transferred between contexts....
List childObjects = new ArrayList(objects.size());
Iterator it = objects.iterator();
while (it.hasNext()) {
Persistent object = (Persistent) it.next();
childObjects.add(targetContext.localObject(object
.getObjectId(), object));
}
childResponse.addResultList(childObjects);
}
}
else {
childResponse.addBatchUpdateCount(response.currentUpdateCount());
}
}
response = childResponse;
}
}
protected boolean interceptOIDQuery() {
if (query instanceof ObjectIdQuery) {
ObjectIdQuery oidQuery = (ObjectIdQuery) query;
if (!oidQuery.isFetchMandatory() && !oidQuery.isFetchingDataRows()) {
Object object = actingContext.getGraphManager().getNode(
oidQuery.getObjectId());
if (object != null) {
this.response = new ListResponse(object);
return DONE;
}
}
}
return !DONE;
}
protected boolean interceptRelationshipQuery() {
if (query instanceof RelationshipQuery) {
RelationshipQuery relationshipQuery = (RelationshipQuery) query;
if (!relationshipQuery.isRefreshing()) {
// don't intercept to-many relationships if fetch is done to the same
// context as the root context of this action - this will result in an
// infinite loop.
if (targetContext == null
&& relationshipQuery.getRelationship(
actingContext.getEntityResolver()).isToMany()) {
return !DONE;
}
ObjectId id = relationshipQuery.getObjectId();
Object object = actingContext.getGraphManager().getNode(id);
if (object != null) {
ClassDescriptor descriptor = actingContext
.getEntityResolver()
.getClassDescriptor(id.getEntityName());
if (!descriptor.isFault(object)) {
ArcProperty property = (ArcProperty) descriptor
.getProperty(relationshipQuery.getRelationshipName());
if (!property.isFault(object)) {
Object related = property.readPropertyDirectly(object);
List result;
// null to-one
if (related == null) {
result = new ArrayList(1);
}
// to-many
else if (related instanceof List) {
result = (List) related;
}
// non-null to-one
else {
result = new ArrayList(1);
result.add(related);
}
this.response = new ListResponse(result);
return DONE;
}
}
}
}
}
return !DONE;
}
/**
* Fetches data from the channel.
*/
protected void runQuery() {
this.response = actingContext.getChannel().onQuery(actingContext, query);
}
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