/*
* 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.
*/
package org.apache.tomcat.util.threads;
import java.util.Collections;
import java.util.List;
import java.util.concurrent.AbstractExecutorService;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.RejectedExecutionException;
import java.util.concurrent.TimeUnit;
import org.apache.tomcat.util.compat.JreCompat;
import org.apache.tomcat.util.res.StringManager;
/**
* An executor that uses a new virtual thread for each task.
*/
public class VirtualThreadExecutor extends AbstractExecutorService {
private static final StringManager sm = StringManager.getManager(VirtualThreadExecutor.class);
private final CountDownLatch shutdown = new CountDownLatch(1);
private final JreCompat jreCompat = JreCompat.getInstance();
private Object threadBuilder;
public VirtualThreadExecutor(String namePrefix) {
threadBuilder = jreCompat.createVirtualThreadBuilder(namePrefix);
}
@Override
public void execute(Runnable command) {
if (isShutdown()) {
throw new RejectedExecutionException(
sm.getString("virtualThreadExecutor.taskRejected", command.toString(), this.toString()));
}
jreCompat.threadBuilderStart(threadBuilder, command);
}
@Override
public void shutdown() {
shutdown.countDown();
}
/**
* {@inheritDoc}
* <p>
* The VirtualThreadExecutor does not track in-progress tasks so calling this method is equivalent to calling
* {@link #shutdown()}.
*/
@Override
public List<Runnable> shutdownNow() {
shutdown();
return Collections.emptyList();
}
@Override
public boolean isShutdown() {
return shutdown.getCount() == 0;
}
/**
* {@inheritDoc}
* <p>
* The VirtualThreadExecutor does not track in-progress tasks so calling this method is equivalent to calling
* {@link #isShutdown()}.
*/
@Override
public boolean isTerminated() {
return isShutdown();
}
/**
* {@inheritDoc}
* <p>
* The VirtualThreadExecutor does not track in-progress tasks so calling this method is effectively waiting for
* {@link #shutdown()} to be called.
*/
@Override
public boolean awaitTermination(long timeout, TimeUnit unit) throws InterruptedException {
return shutdown.await(timeout, unit);
}
}