/*
* Copyright (C) 2010 Google Inc
*
* Licensed 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 under the License.
*/
package com.google.appengine.datanucleus;
import com.google.appengine.api.datastore.Cursor;
import com.google.appengine.api.datastore.Entity;
import org.datanucleus.ClassLoaderResolver;
import org.datanucleus.ExecutionContext;
import org.datanucleus.store.StoreManager;
import org.datanucleus.store.connection.ManagedConnection;
import org.datanucleus.store.connection.ManagedConnectionResourceListener;
import org.datanucleus.metadata.AbstractClassMetaData;
import com.google.appengine.datanucleus.query.DatastoreQuery;
import org.datanucleus.store.query.AbstractJavaQuery;
import org.datanucleus.store.query.AbstractQueryResult;
import java.util.List;
import java.util.Map;
/**
* Utilities for converting between the low-level datastore api and pojos.
*
* @author Max Ross <max.ross@gmail.com>
*/
class PojoDatastoreBridge {
<T> List<T> toPojoResult(final ExecutionContext ec, Class<T> cls, Iterable<Entity> queryResultIterable, Cursor endCursor) {
final ClassLoaderResolver clr = ec.getClassLoaderResolver();
final AbstractClassMetaData acmd = ec.getMetaDataManager().getMetaDataForClass(cls, clr);
Utils.Function<Entity, Object> func = new Utils.Function<Entity, Object>() {
public Object apply(Entity from) {
return EntityUtils.entityToPojo(from, acmd, clr, ec, true, ec.getFetchPlan().getCopy());
}
};
AbstractJavaQuery query = new DummyQuery(ec.getStoreManager(), ec);
final ManagedConnection mconn = ec.getStoreManager().getConnection(ec);
try {
List<T> results = (List<T>) DatastoreQuery.newStreamingQueryResultForEntities(
queryResultIterable, func, endCursor, query);
if (results instanceof AbstractQueryResult) {
// Lazy loading results : add listener to the connection so we can get a callback when the connection is flushed.
final AbstractQueryResult qr = (AbstractQueryResult)results;
ManagedConnectionResourceListener listener = new ManagedConnectionResourceListener() {
public void managedConnectionPreClose() {
// Disconnect the query from this ManagedConnection (read in unread rows etc)
qr.disconnect();
}
public void managedConnectionPostClose() {}
public void resourcePostClose() {
mconn.removeListener(this);
}
public void transactionFlushed() {}
public void transactionPreClose() {
// Disconnect the query from this ManagedConnection (read in unread rows etc)
qr.disconnect();
}
};
mconn.addListener(listener);
qr.addConnectionListener(listener);
}
return results;
} finally {
mconn.release();
}
}
private static final class DummyQuery extends AbstractJavaQuery {
private DummyQuery(StoreManager storeMgr, ExecutionContext ec) {
super(storeMgr, ec);
}
public String getSingleStringQuery() {
throw new UnsupportedOperationException();
}
protected void compileInternal(Map parameterValues) {
throw new UnsupportedOperationException();
}
protected Object performExecute(Map parameters) {
throw new UnsupportedOperationException();
}
}
}