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Spring Cloud Contract Shaded Dependencies
package org.eclipse.aether.util.concurrency;
/*
* 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.
*/
import static java.util.Objects.requireNonNull;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.atomic.AtomicReference;
import java.util.concurrent.locks.LockSupport;
/**
* A utility class to forward any uncaught {@link Error} or {@link RuntimeException} from a {@link Runnable} executed in
* a worker thread back to the parent thread. The simplified usage pattern looks like this:
*
*
* RunnableErrorForwarder errorForwarder = new RunnableErrorForwarder();
* for ( Runnable task : tasks )
* {
* executor.execute( errorForwarder.wrap( task ) );
* }
* errorForwarder.await();
*
*/
public final class RunnableErrorForwarder
{
private final Thread thread = Thread.currentThread();
private final AtomicInteger counter = new AtomicInteger();
private final AtomicReference error = new AtomicReference<>();
/**
* Creates a new error forwarder for worker threads spawned by the current thread.
*/
public RunnableErrorForwarder()
{
}
/**
* Wraps the specified runnable into an equivalent runnable that will allow forwarding of uncaught errors.
*
* @param runnable The runnable from which to forward errors, must not be {@code null}.
* @return The error-forwarding runnable to eventually execute, never {@code null}.
*/
public Runnable wrap( final Runnable runnable )
{
requireNonNull( runnable, "runnable cannot be null" );
counter.incrementAndGet();
return new Runnable()
{
public void run()
{
try
{
runnable.run();
}
catch ( RuntimeException | Error e )
{
error.compareAndSet( null, e );
throw e;
}
finally
{
counter.decrementAndGet();
LockSupport.unpark( thread );
}
}
};
}
/**
* Causes the current thread to wait until all previously {@link #wrap(Runnable) wrapped} runnables have terminated
* and potentially re-throws an uncaught {@link RuntimeException} or {@link Error} from any of the runnables. In
* case multiple runnables encountered uncaught errors, one error is arbitrarily selected. Note: This
* method must be called from the same thread that created this error forwarder instance.
*/
public void await()
{
awaitTerminationOfAllRunnables();
Throwable error = this.error.get();
if ( error != null )
{
if ( error instanceof RuntimeException )
{
throw (RuntimeException) error;
}
else if ( error instanceof ThreadDeath )
{
throw new IllegalStateException( error );
}
else if ( error instanceof Error )
{
throw (Error) error;
}
throw new IllegalStateException( error );
}
}
private void awaitTerminationOfAllRunnables()
{
if ( !thread.equals( Thread.currentThread() ) )
{
throw new IllegalStateException( "wrong caller thread, expected " + thread + " and not "
+ Thread.currentThread() );
}
boolean interrupted = false;
while ( counter.get() > 0 )
{
LockSupport.park();
if ( Thread.interrupted() )
{
interrupted = true;
}
}
if ( interrupted )
{
Thread.currentThread().interrupt();
}
}
}