/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* 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 under the License.
*/
package org.apache.jena.sparql.core ;
import static org.apache.jena.atlas.iterator.Iter.take ;
import java.util.Iterator ;
import java.util.List ;
import org.apache.jena.graph.Graph ;
import org.apache.jena.graph.Node ;
import org.apache.jena.graph.Triple ;
import org.apache.jena.sparql.SystemARQ ;
import org.apache.jena.util.iterator.ExtendedIterator ;
/** Connect a DatasetGraph to a DatasetChanges monitor.
* Any add or delete to the DatasetGraph is notified to the
* monitoring object with a {@link QuadAction} to indicate
* the change made.
*/
public class DatasetGraphMonitor extends DatasetGraphWrapper
{
/** Whether to see if a quad action will change the dataset - test before add for existence, test before delete for absence */
private boolean CheckFirst = true ;
/** Whether to record a no-op (maybe as a comment) */
private boolean RecordNoAction = true ;
/** Where to send the notifications */
private final DatasetChanges monitor ;
/**
* Create a DatasetGraph wrapper that monitors the dataset for changes (add or delete quads).
* Use this DatasetGraph for all operations in order to record changes.
* Note whether additions of deletions cause an actual change to the dataset or not.
* @param dsg The DatasetGraph to monitor
* @param monitor The handler for a change
*
* @see DatasetChanges
* @see QuadAction
*/
public DatasetGraphMonitor(DatasetGraph dsg, DatasetChanges monitor)
{
super(dsg) ;
this.monitor = monitor ;
}
/**
* Create a DatasetGraph wrapper that monitors the dataset for changes (add or delete quads).
* Use this DatasetGraph for all operations in order to record changes.
* @param dsg The DatasetGraph to monitor
* @param monitor The handler for a change
* @param recordOnlyIfRealChange
* If true, check to see if the change would have an effect (e.g. add is a new quad).
* If false, log changes as ADD/DELETE regardless of whether the dataset actually changes.
*
* @see DatasetChanges
* @see QuadAction
*/
public DatasetGraphMonitor(DatasetGraph dsg, DatasetChanges monitor, boolean recordOnlyIfRealChange)
{
super(dsg) ;
CheckFirst = recordOnlyIfRealChange ;
this.monitor = monitor ;
}
/** Return the monitor */
public DatasetChanges getMonitor() { return monitor ; }
/** Return the monitored DatasetGraph */
public DatasetGraph monitored() { return getWrapped() ; }
@Override public void add(Quad quad)
{
if ( CheckFirst && contains(quad) )
{
if ( RecordNoAction )
record(QuadAction.NO_ADD, quad.getGraph(), quad.getSubject(), quad.getPredicate(), quad.getObject()) ;
return ;
}
add$(quad) ;
}
@Override public void add(Node g, Node s, Node p, Node o)
{
if ( CheckFirst && contains(g,s,p,o) )
{
if ( RecordNoAction )
record(QuadAction.NO_ADD,g,s,p,o) ;
return ;
}
add$(g,s,p,o) ;
}
private void add$(Node g, Node s, Node p, Node o)
{
super.add(g,s,p,o) ;
record(QuadAction.ADD,g,s,p,o) ;
}
private void add$(Quad quad)
{
super.add(quad) ;
record(QuadAction.ADD, quad.getGraph(), quad.getSubject(), quad.getPredicate(), quad.getObject()) ;
}
@Override public void delete(Quad quad)
{
if ( CheckFirst && ! contains(quad) )
{
if ( RecordNoAction )
record(QuadAction.NO_DELETE, quad.getGraph(), quad.getSubject(), quad.getPredicate(), quad.getObject()) ;
return ;
}
delete$(quad) ;
}
@Override public void delete(Node g, Node s, Node p, Node o)
{
if ( CheckFirst && ! contains(g,s,p,o) )
{
if ( RecordNoAction )
record(QuadAction.NO_DELETE, g,s,p,o) ;
return ;
}
delete$(g,s,p,o) ;
}
private void delete$(Quad quad)
{
super.delete(quad) ;
record(QuadAction.DELETE, quad.getGraph(), quad.getSubject(), quad.getPredicate(), quad.getObject()) ;
}
private void delete$(Node g, Node s, Node p, Node o)
{
super.delete(g,s,p,o) ;
record(QuadAction.DELETE,g,s,p,o) ;
}
private static int SLICE = 1000 ;
@Override
public void deleteAny(Node g, Node s, Node p, Node o)
{
while (true)
{
Iterator<Quad> iter = find(g, s, p, o) ;
// Materialize - stops possible ConcurrentModificationExceptions
List<Quad> some = take(iter, SLICE) ;
for (Quad q : some)
delete$(q) ;
if (some.size() < SLICE) break ;
}
}
@Override public void addGraph(Node gn, Graph g)
{
// Convert to quads.
//super.addGraph(gn, g) ;
ExtendedIterator<Triple> iter = g.find(Node.ANY, Node.ANY, Node.ANY) ;
for ( ; iter.hasNext(); )
{
Triple t = iter.next() ;
add(gn, t.getSubject(), t.getPredicate(), t.getObject()) ;
}
}
@Override public void removeGraph(Node gn)
{
//super.removeGraph(gn) ;
deleteAny(gn, Node.ANY, Node.ANY, Node.ANY) ;
}
private void record(QuadAction action, Node g, Node s, Node p, Node o)
{
monitor.change(action, g, s, p, o) ;
}
@Override
public void sync() {
SystemARQ.syncObject(monitor) ;
super.sync() ;
}
}