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/*****************************************************************************
* Copyright (c) 2015, 2018 Christian W. Damus and others.
*
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* Christian W. Damus - Initial API and implementation
*
*****************************************************************************/
package org.eclipse.papyrus.infra.core.utils;
import java.util.Collections;
import java.util.Map;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.Executor;
import java.util.concurrent.LinkedBlockingQueue;
import java.util.concurrent.atomic.AtomicBoolean;
import org.eclipse.emf.common.command.Command;
import org.eclipse.emf.transaction.RecordingCommand;
import org.eclipse.emf.transaction.Transaction;
import org.eclipse.emf.transaction.TransactionalEditingDomain;
import org.eclipse.emf.transaction.TransactionalEditingDomainEvent;
import org.eclipse.emf.transaction.TransactionalEditingDomainListener;
import org.eclipse.emf.transaction.impl.EMFCommandTransaction;
import org.eclipse.emf.transaction.impl.InternalTransactionalCommandStack;
import org.eclipse.emf.transaction.util.TransactionUtil;
import org.eclipse.papyrus.infra.core.Activator;
import com.google.common.collect.Maps;
/**
* An {@link Executor} that executes {@link Runnable}s at the pre-commit phase of the active
* write transaction of a {@link TransactionalEditingDomain} or at some other time if no
* write transaction is active.
*/
class TransactionPrecommitExecutor implements Executor, TransactionalEditingDomainListener {
private final TransactionalEditingDomain editingDomain;
private final Executor fallback;
private final AtomicBoolean writeActive = new AtomicBoolean();
private final BlockingQueue<Runnable> queue = new LinkedBlockingQueue<Runnable>();
private final IExecutorPolicy policy;
private final Map<?, ?> options;
private final AtomicBoolean disposed = new AtomicBoolean();
TransactionPrecommitExecutor(TransactionalEditingDomain domain, Executor fallback, IExecutorPolicy policy, Map<?, ?> options) {
super();
this.editingDomain = domain;
this.fallback = fallback;
this.policy = (policy == null) ? IExecutorPolicy.NULL : policy;
this.options = ((options != null) && options.isEmpty()) ? null : options;
TransactionUtil.getAdapter(domain, TransactionalEditingDomain.Lifecycle.class).addTransactionalEditingDomainListener(this);
}
/**
* Disposes me. This entails at least desisting in listening to lifecycle changes in
* my editing domain.
*/
public void dispose() {
if (disposed.compareAndSet(false, true)) {
TransactionalEditingDomain.Lifecycle lifecycle = TransactionUtil.getAdapter(editingDomain, TransactionalEditingDomain.Lifecycle.class);
if (lifecycle != null) {
lifecycle.removeTransactionalEditingDomainListener(this);
}
}
}
@Override
public void execute(Runnable command) {
if (disposed.get()) {
return;
}
if (writeActive.get() && selectSelf(command)) {
queue.offer(command);
} else {
fallback.execute(command);
}
}
private boolean selectSelf(Runnable task) {
return IExecutorPolicy.Ranking.select(policy, task, this, fallback) == this;
}
//
// Editing Domain Lifecycle handling
//
@Override
public void editingDomainDisposing(TransactionalEditingDomainEvent event) {
queue.clear();
}
//
// Transaction lifecycle handling
//
@Override
public void transactionStarted(TransactionalEditingDomainEvent event) {
// We should only attempt to record triggers in a transaction that has triggers enabled.
// In particular, unprotected writes are in an otherwise read-only context and should be
// treated as such
final Transaction transaction = event.getTransaction();
writeActive.set(!transaction.isReadOnly() && hasTriggersEnabled(transaction));
}
private boolean hasTriggersEnabled(Transaction transaction) {
final Map<?, ?> options = transaction.getOptions();
return !Boolean.TRUE.equals(options.get(Transaction.OPTION_UNPROTECTED))
&& !Boolean.TRUE.equals(options.get(Transaction.OPTION_NO_TRIGGERS))
&& !Boolean.TRUE.equals(options.get(Transaction.OPTION_IS_UNDO_REDO_TRANSACTION));
}
@Override
public void transactionClosed(TransactionalEditingDomainEvent event) {
writeActive.set(false);
if (queue.peek() != null) {
// Punt the remaining tasks
for (Runnable next = queue.poll(); next != null; next = queue.poll()) {
fallback.execute(next);
}
}
}
@Override
public void transactionStarting(TransactionalEditingDomainEvent event) {
// Pass
}
@Override
public void transactionInterrupted(TransactionalEditingDomainEvent event) {
// Pass
}
@Override
public void transactionClosing(TransactionalEditingDomainEvent event) {
if (queue.peek() != null) {
// Inject tasks into the transaction as a trigger command
Command trigger = new RecordingCommand(event.getSource(), "Deferred Tasks") {
@Override
protected void doExecute() {
for (Runnable next = queue.poll(); next != null; next = queue.poll()) {
try {
next.run();
} catch (Exception e) {
Activator.log.error("Uncaught exception in transaction pre-commit task.", e); //$NON-NLS-1$
}
}
}
};
final Transaction transaction = event.getTransaction();
final Command triggeringCommand;
if (transaction instanceof EMFCommandTransaction) {
triggeringCommand = ((EMFCommandTransaction) transaction).getCommand();
} else {
triggeringCommand = null;
}
final InternalTransactionalCommandStack stack = (InternalTransactionalCommandStack) event.getSource().getCommandStack();
try {
Map<?, ?> options = transaction.getOptions();
Map<Object, Object> mergedOptions = null;
if (this.options != null) {
options = (mergedOptions == null) ? (mergedOptions = Maps.newHashMap(options)) : mergedOptions;
mergedOptions.putAll(this.options);
}
if (transaction.isReadOnly()) {
// Must use an unprotected write transaction
options = (mergedOptions == null) ? (mergedOptions = Maps.newHashMap(options)) : mergedOptions;
mergedOptions.put(Transaction.OPTION_UNPROTECTED, true);
}
stack.executeTriggers(triggeringCommand, Collections.singletonList(trigger), options);
} catch (Exception e) {
Activator.log.error("Failed to execute transaction pre-commit tasks.", e); //$NON-NLS-1$
}
}
}
}
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