/*
* 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.rulesys.impl;
import java.util.*;
import org.apache.jena.reasoner.rulesys.* ;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* The final node in a RETE graph. It runs the builtin guard clauses
* and then, if the token passes, executes the head operations.
*/
public class RETETerminal implements RETESinkNode {
/** Context containing the specific rule and parent graph */
protected RETERuleContext context;
protected static Logger logger = LoggerFactory.getLogger(FRuleEngine.class);
/**
* Constructor.
* @param rule the rule which this terminal should fire.
* @param engine the parent rule engine through which the deductions and recursive network can be reached.
* @param graph the wider encompasing infGraph needed to for the RuleContext
*/
public RETETerminal(Rule rule, RETEEngine engine, ForwardRuleInfGraphI graph) {
context = new RETERuleContext(graph, engine);
context.rule = rule;
}
/**
* Constructor. Used internally for cloning.
* @param rule the rule which this terminal should fire.
* @param engine the parent rule engine through which the deductions and recursive network can be reached.
* @param graph the wider encompasing infGraph needed to for the RuleContext
*/
protected RETETerminal(RETERuleContext context) {
this.context = context;
}
/**
* Change the engine/graph to which this terminal should deliver its results.
*/
public void setContext(RETEEngine engine, ForwardRuleInfGraphI graph) {
Rule rule = context.getRule();
context = new RETERuleContext(graph, engine);
context.setRule(rule);
}
/**
* Propagate a token to this node.
* @param env a set of variable bindings for the rule being processed.
* @param isAdd distinguishes between add and remove operations.
*/
@Override
public void fire(BindingVector env, boolean isAdd) {
Rule rule = context.getRule();
context.setEnv(env);
if (! context.shouldFire(isAdd)) return;
// Now fire the rule
context.getEngine().requestRuleFiring(rule, env, isAdd);
}
/**
* Clone this node in the network.
* @param netCopy a map from RETENode to cloned instance
* @param contextIn the new context to which the network is being ported
*/
@Override
public RETENode clone(Map<RETENode, RETENode> netCopy, RETERuleContext contextIn) {
RETETerminal clone = (RETETerminal)netCopy.get(this);
if (clone == null) {
RETERuleContext newContext = new RETERuleContext((ForwardRuleInfGraphI)contextIn.getGraph(), contextIn.getEngine());
newContext.setRule(context.getRule());
clone = new RETETerminal(newContext);
netCopy.put(this, clone);
}
return clone;
}
}