/*
* 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 com.hp.hpl.jena.reasoner.rulesys.impl;
import com.hp.hpl.jena.graph.*;
import com.hp.hpl.jena.reasoner.TriplePattern;
import java.util.*;
/**
* Extension of the normal AND-stack environment frame to support
* incremental derivation logging.
*/
public class EnvironmentFrameWithDerivation extends EnvironmentFrame {
/** The initial starting arguments for the call */
Node[] argVars = new Node[RuleClauseCode.MAX_ARGUMENT_VARS];
/** The set of instantiated subgoals processed so far */
TriplePattern[] matches;
/**
* Constructor
* @param clause the compiled code being interpreted by this env frame
*/
public EnvironmentFrameWithDerivation(RuleClauseCode clause) {
super(clause);
if (clause.getRule() != null) {
matches = new TriplePattern[clause.getRule().bodyLength()];
}
}
/** Instantiate and record a matched subgoal */
public void noteMatch(TriplePattern pattern, int pc) {
TriplePattern match = pattern;
int term = clause.termIndex(pc);
if (term >= 0) {
matches[term] = match;
}
}
/**
* Return the final instantiated goal given the current binding state.
*/
public Triple getResult() {
return new Triple(
LPInterpreter.deref(argVars[0]),
LPInterpreter.deref(argVars[1]),
LPInterpreter.derefPossFunctor(argVars[2]));
}
/**
* Return a safe copy of the list of matched subgoals in this subderivation.
*/
public List<Triple> getMatchList() {
ArrayList<Triple> matchList = new ArrayList<Triple>();
for (int i = 0; i < matches.length; i++) {
matchList.add( LPInterpreter.deref(matches[i]));
}
return matchList;
}
/**
* Create an initial derivation record for this frame, based on the given
* argument registers.
*/
public void initDerivationRecord(Node[] args) {
System.arraycopy(args, 0, argVars, 0, RuleClauseCode.MAX_ARGUMENT_VARS);
}
}