/*
* 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.reasoner;
import org.apache.jena.graph.* ;
import org.apache.jena.util.iterator.* ;
/**
* Wrapper round a Graph to implement the slighly modified Finder
* interface.
*/
public class FGraph implements Finder {
/** The graph being searched */
protected Graph graph;
/**
* Constructor
*/
public FGraph(Graph graph) {
this.graph = graph;
}
/**
* Basic pattern lookup interface.
* @param pattern a TriplePattern to be matched against the data
* @return a ClosableIterator over all Triples in the data set
* that match the pattern
*/
@Override
public ExtendedIterator<Triple> find(TriplePattern pattern) {
if (graph == null) return new NullIterator<>();
return graph.find(pattern.asTripleMatch());
}
/**
* Extended find interface used in situations where the implementator
* may or may not be able to answer the complete query. It will
* attempt to answer the pattern but if its answers are not known
* to be complete then it will also pass the request on to the nested
* Finder to append more results.
* @param pattern a TriplePattern to be matched against the data
* @param continuation either a Finder or a normal Graph which
* will be asked for additional match results if the implementor
* may not have completely satisfied the query.
*/
@Override
public ExtendedIterator<Triple> findWithContinuation(TriplePattern pattern, Finder continuation) {
if (graph == null) return new NullIterator<>();
if (continuation == null) {
return graph.find(pattern.asTripleMatch());
} else {
return graph.find(pattern.asTripleMatch()).andThen(continuation.find(pattern));
}
}
/**
* Returns the graph.
* @return Graph
*/
public Graph getGraph() {
return graph;
}
/**
* Return true if the given pattern occurs somewhere in the find sequence.
*/
@Override
public boolean contains(TriplePattern pattern) {
return graph.contains(pattern.getSubject(), pattern.getPredicate(), pattern.getObject());
}
}