/*
* Copyright 2003-2014 JetBrains s.r.o.
*
* 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 jetbrains.mps.smodel;
import jetbrains.mps.util.Computable;
import jetbrains.mps.util.ComputeRunnable;
import org.apache.log4j.LogManager;
import org.apache.log4j.Logger;
import org.jetbrains.mps.openapi.repository.WriteActionListener;
import java.util.List;
import java.util.concurrent.CopyOnWriteArrayList;
public final class WriteActionDispatcher {
private static final Logger LOG = LogManager.getLogger(WriteActionDispatcher.class);
private final List<WriteActionListener> myListeners = new CopyOnWriteArrayList<WriteActionListener>();
private volatile int myWriteActionLevel = 0;
public void run(Runnable r) {
if (myWriteActionLevel == 0) onActionStarted();
++myWriteActionLevel;
try {
LOG.trace("Write action started");
r.run();
} finally {
LOG.trace("Write action finished");
--myWriteActionLevel;
if (myWriteActionLevel == 0) onActionFinished();
}
}
public <T> T compute(Computable<T> c) {
ComputeRunnable<T> cr = new ComputeRunnable<T>(c);
run(cr);
return cr.getResult();
}
private void onActionStarted() {
for (WriteActionListener listener : myListeners) {
listener.actionStarted();
}
}
private void onActionFinished() {
for (WriteActionListener listener : myListeners) {
listener.actionFinished();
}
}
private boolean inWriteAction() {
return myWriteActionLevel > 0;
}
public void addWriteActionListener(WriteActionListener listener) {
if (myListeners.contains(listener)) throw new ListenersConsistenceException("Adding the same listener again");
if (inWriteAction()) listener.actionStarted();
myListeners.add(listener);
}
public void removeWriteActionListener(WriteActionListener listener) {
if (!myListeners.contains(listener)) throw new ListenersConsistenceException("The listener you trying to remove does not exist");
if (inWriteAction()) listener.actionFinished();
myListeners.remove(listener);
}
private static class ListenersConsistenceException extends RuntimeException {
public ListenersConsistenceException(String msg) {
super(msg);
}
}
}