de.learnlib.algorithms.adt.util.SQOOTBridge Maven / Gradle / Ivy
/* Copyright (C) 2013-2018 TU Dortmund
* This file is part of LearnLib, http://www.learnlib.de/.
*
* Licensed 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 de.learnlib.algorithms.adt.util;
import java.util.ArrayList;
import java.util.List;
import javax.annotation.ParametersAreNonnullByDefault;
import de.learnlib.algorithms.adt.model.ObservationTree;
import de.learnlib.api.oracle.SymbolQueryOracle;
import net.automatalib.automata.transout.impl.FastMealy;
import net.automatalib.automata.transout.impl.FastMealyState;
/**
* A utility class that links an observation tree with a symbol query oracle, meaning that all queries to the symbol
* query oracle will be stored in the observation tree. Additionally, if a query can be answered by the observation tree
* (and caching is enabled) the delegated symbol query oracle will not be queried.
*
* @param
* input alphabet type
* @param
* output alphabet type
*
* @author frohme
*/
@ParametersAreNonnullByDefault
public class SQOOTBridge implements SymbolQueryOracle {
private final FastMealy observationTree;
private final SymbolQueryOracle delegate;
private final boolean enableCache;
private final List currentTrace;
private FastMealyState currentState;
private boolean currentTraceValid;
public SQOOTBridge(final ObservationTree observationTree,
final SymbolQueryOracle delegate,
final boolean enableCache) {
this.observationTree = observationTree.getObservationTree();
this.delegate = delegate;
this.enableCache = enableCache;
this.currentTrace = new ArrayList<>();
}
public void initialize() {
this.currentState = this.observationTree.getInitialState();
this.currentTraceValid = enableCache;
}
@Override
public O query(I i) {
if (this.currentTraceValid) {
final FastMealyState succ = this.observationTree.getSuccessor(this.currentState, i);
if (succ != null) {
final O output = this.observationTree.getOutput(this.currentState, i);
this.currentTrace.add(i);
this.currentState = succ;
return output;
} else {
this.currentTraceValid = false;
this.delegate.reset();
for (final I trace : this.currentTrace) {
this.delegate.query(trace);
}
}
}
final O output = this.delegate.query(i);
final FastMealyState nextState;
final FastMealyState succ = this.observationTree.getSuccessor(this.currentState, i);
if (succ == null) {
final FastMealyState newState = this.observationTree.addState();
this.observationTree.addTransition(this.currentState, i, newState, output);
nextState = newState;
} else {
assert this.observationTree.getOutput(this.currentState, i).equals(output) : "Inconsistent observations";
nextState = succ;
}
this.currentState = nextState;
return output;
}
@Override
public void reset() {
this.currentState = this.observationTree.getInitialState();
if (this.enableCache) {
this.currentTrace.clear();
this.currentTraceValid = true;
} else {
this.delegate.reset();
}
}
}