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/*******************************************************************************
* Copyright (c) 2010-2013, Abel Hegedus, Istvan Rath and Daniel Varro
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License v. 2.0 which is available at
* http://www.eclipse.org/legal/epl-v20.html.
*
* SPDX-License-Identifier: EPL-2.0
*******************************************************************************/
package tools.refinery.viatra.runtime.internal.engine;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.EnumMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Map.Entry;
import org.apache.log4j.Logger;
import tools.refinery.viatra.runtime.api.AdvancedViatraQueryEngine;
import tools.refinery.viatra.runtime.api.IMatchUpdateListener;
import tools.refinery.viatra.runtime.api.IPatternMatch;
import tools.refinery.viatra.runtime.api.ViatraQueryEngineLifecycleListener;
import tools.refinery.viatra.runtime.api.ViatraQueryMatcher;
import tools.refinery.viatra.runtime.api.ViatraQueryModelUpdateListener;
import tools.refinery.viatra.runtime.api.ViatraQueryModelUpdateListener.ChangeLevel;
import tools.refinery.viatra.runtime.api.scope.ViatraBaseIndexChangeListener;
import tools.refinery.viatra.runtime.exception.ViatraQueryException;
import tools.refinery.viatra.runtime.matchers.util.CollectionsFactory;
public final class ModelUpdateProvider extends ListenerContainer<ViatraQueryModelUpdateListener> {
private final AdvancedViatraQueryEngine queryEngine;
private ChangeLevel currentChange = ChangeLevel.NO_CHANGE;
private ChangeLevel maxLevel = ChangeLevel.NO_CHANGE;
private final Map<ChangeLevel, Collection<ViatraQueryModelUpdateListener>> listenerMap;
private final Logger logger;
public ModelUpdateProvider(AdvancedViatraQueryEngine queryEngine, Logger logger) {
super();
this.queryEngine = queryEngine;
this.logger = logger;
listenerMap = new EnumMap<>(ChangeLevel.class);
}
@Override
protected void listenerAdded(ViatraQueryModelUpdateListener listener) {
// check ChangeLevel
// create callback for given level if required
if(listenerMap.isEmpty()) {
try {
this.queryEngine.getBaseIndex().addBaseIndexChangeListener(indexListener);
// add listener to new matchers (use lifecycle listener)
this.queryEngine.addLifecycleListener(selfListener);
} catch (ViatraQueryException e) {
throw new IllegalStateException("Model update listener used on engine without base index", e);
}
}
ChangeLevel changeLevel = listener.getLevel();
listenerMap.computeIfAbsent(changeLevel, k -> CollectionsFactory.createSet()).add(listener);
// increase or keep max level of listeners
ChangeLevel oldMaxLevel = maxLevel;
maxLevel = maxLevel.changeOccured(changeLevel);
if(!maxLevel.equals(oldMaxLevel) && ChangeLevel.MATCHSET.compareTo(oldMaxLevel) > 0 && ChangeLevel.MATCHSET.compareTo(maxLevel) <= 0) {
// add matchUpdateListener to all matchers
for (ViatraQueryMatcher<?> matcher : this.queryEngine.getCurrentMatchers()) {
this.queryEngine.addMatchUpdateListener(matcher, matchSetListener, false);
}
}
}
@Override
protected void listenerRemoved(ViatraQueryModelUpdateListener listener) {
ChangeLevel changeLevel = listener.getLevel();
Collection<ViatraQueryModelUpdateListener> old = listenerMap.getOrDefault(changeLevel, Collections.emptySet());
boolean removed = old.remove(listener);
if(removed) {
if (old.isEmpty()) listenerMap.remove(changeLevel);
} else {
handleUnsuccesfulRemove(listener);
}
updateMaxLevel();
if(listenerMap.isEmpty()) {
this.queryEngine.removeLifecycleListener(selfListener);
removeBaseIndexChangeListener();
}
}
private void removeBaseIndexChangeListener() {
try {
this.queryEngine.getBaseIndex().removeBaseIndexChangeListener(indexListener);
} catch (ViatraQueryException e) {
throw new IllegalStateException("Model update listener used on engine without base index", e);
}
}
private void updateMaxLevel() {
if(!listenerMap.containsKey(maxLevel)) {
ChangeLevel newMaxLevel = ChangeLevel.NO_CHANGE;
for (ChangeLevel level : new HashSet<>(listenerMap.keySet())) {
newMaxLevel = newMaxLevel.changeOccured(level);
}
maxLevel = newMaxLevel;
}
if(maxLevel.compareTo(ChangeLevel.MATCHSET) < 0) {
// remove listener from matchers
for (ViatraQueryMatcher<?> matcher : this.queryEngine.getCurrentMatchers()) {
this.queryEngine.removeMatchUpdateListener(matcher, matchSetListener);
}
}
}
private void handleUnsuccesfulRemove(ViatraQueryModelUpdateListener listener) {
for (Entry<ChangeLevel, Collection<ViatraQueryModelUpdateListener>> entry : listenerMap.entrySet()) {
Collection<ViatraQueryModelUpdateListener> existingListeners = entry.getValue();
// if the listener is contained in some other bucket, remove it from there
if(existingListeners.remove(listener)) {
logger.error("Listener "+listener+" change level changed since initialization!");
if (existingListeners.isEmpty()) listenerMap.remove(entry.getKey());
return; // listener is contained only once
}
}
logger.error("Listener "+listener+" already removed from map (e.g. engine was already disposed)!");
}
private void notifyListeners() {
// any change that occurs after this point should be regarded as a new event
// FIXME what should happen when a listener creates new notifications?
// -> other listeners will get events in different order
ChangeLevel tempLevel = currentChange;
currentChange = ChangeLevel.NO_CHANGE;
if(!listenerMap.isEmpty()) {
for (ChangeLevel level : new HashSet<>(listenerMap.keySet())) {
if(tempLevel.compareTo(level) >= 0) {
for (ViatraQueryModelUpdateListener listener : new ArrayList<>(listenerMap.get(level))) {
try {
listener.notifyChanged(tempLevel);
} catch (Exception ex) {
logger.error(
"VIATRA Query encountered an error in delivering model update notification to listener "
+ listener + ".", ex);
}
}
}
}
} else {
throw new IllegalStateException("Notify listeners must not be called without listeners! Maybe an update callback was not removed correctly.");
}
}
// model update "providers":
// - model: IQBase callback even if not dirty
// - index: IQBase dirty callback
private final ViatraBaseIndexChangeListener indexListener = new ViatraBaseIndexChangeListener() {
@Override
public boolean onlyOnIndexChange() {
return false;
}
@Override
public void notifyChanged(boolean indexChanged) {
if(indexChanged) {
currentChange = currentChange.changeOccured(ChangeLevel.INDEX);
} else {
currentChange = currentChange.changeOccured(ChangeLevel.MODEL);
}
notifyListeners();
}
};
// - matchset: add the same listener to each matcher and use a dirty flag. needs IQBase callback as well
private final IMatchUpdateListener<IPatternMatch> matchSetListener = new IMatchUpdateListener<IPatternMatch>() {
@Override
public void notifyDisappearance(IPatternMatch match) {
currentChange = currentChange.changeOccured(ChangeLevel.MATCHSET);
}
@Override
public void notifyAppearance(IPatternMatch match) {
currentChange = currentChange.changeOccured(ChangeLevel.MATCHSET);
}
};
private final ViatraQueryEngineLifecycleListener selfListener = new ViatraQueryEngineLifecycleListener() {
@Override
public void matcherInstantiated(ViatraQueryMatcher<? extends IPatternMatch> matcher) {
if (maxLevel.compareTo(ChangeLevel.MATCHSET) >= 0) {
ModelUpdateProvider.this.queryEngine.addMatchUpdateListener(matcher, matchSetListener, false);
}
}
@Override
public void engineWiped() {}
@Override
public void engineDisposed() {
removeBaseIndexChangeListener();
listenerMap.clear();
maxLevel = ChangeLevel.NO_CHANGE;
}
@Override
public void engineBecameTainted(String description, Throwable t) {}
};
}
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