/*
* 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.util;
import java.util.*;
import org.apache.jena.graph.Triple ;
import org.apache.jena.rdf.model.* ;
import org.apache.jena.rdf.model.impl.ModelCom ;
/**
* Model wrapper which provides normal access to an underlying model but
* also maintains a snapshot of the triples it was last known to contain.
* A snapshot action
* causes the set of changes between this and the previous snapshot to
* be calculated and the cache updated. The snapshot process will also
* fire change notification.
*/
public class MonitorModel extends ModelCom {
/**
* Create a monitor over the given underlying base model.
*/
public MonitorModel(Model base) {
super(new MonitorGraph(base.getGraph()));
}
/**
* Compute the differences between the current monitored graph and the last
* snapshot. The changes will also be forwarded to any listeners.
* Then take a new snapshot.
* @param additions a place in which the set of newly added statements should be noted, can be null
* @param deletions a place in which the set of newly deleted statements should be noted, can be null
*/
public void snapshot(List<Statement> additions, List<Statement> deletions) {
List<Triple> additionsTemp = (additions != null) ? new ArrayList<Triple>() : null;
List<Triple> deletionsTemp = (deletions != null) ? new ArrayList<Triple>() : null;
((MonitorGraph)getGraph()).snapshot(additionsTemp, deletionsTemp);
if (additions != null) {
for ( Triple anAdditionsTemp : additionsTemp )
{
additions.add( this.asStatement( anAdditionsTemp ) );
}
}
if (deletions != null) {
for ( Triple aDeletionsTemp : deletionsTemp )
{
deletions.add( this.asStatement( aDeletionsTemp ) );
}
}
}
/**
* Compute the differences between the current monitored graph and the last
* snapshot, forward any changes to registered listeners, then take a new snapshot.
*/
public void snapshot() {
snapshot(null, null);
}
}