| /* |
| * 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.cassandra.concurrent; |
| |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| import java.util.concurrent.TimeUnit; |
| |
| import com.google.common.annotations.VisibleForTesting; |
| import java.util.concurrent.atomic.AtomicReferenceFieldUpdater; |
| import java.util.function.BiFunction; |
| import java.util.function.Consumer; |
| |
| import org.apache.cassandra.utils.Shared; |
| import org.apache.cassandra.utils.concurrent.Condition; |
| import org.apache.cassandra.utils.concurrent.UncheckedInterruptedException; |
| |
| import static org.apache.cassandra.concurrent.InfiniteLoopExecutor.InternalState.SHUTTING_DOWN_NOW; |
| import static org.apache.cassandra.concurrent.InfiniteLoopExecutor.InternalState.TERMINATED; |
| import static org.apache.cassandra.concurrent.InfiniteLoopExecutor.Interrupts.SYNCHRONIZED; |
| import static org.apache.cassandra.concurrent.InfiniteLoopExecutor.Interrupts.UNSYNCHRONIZED; |
| import static org.apache.cassandra.concurrent.Interruptible.State.INTERRUPTED; |
| import static org.apache.cassandra.concurrent.Interruptible.State.NORMAL; |
| import static org.apache.cassandra.concurrent.Interruptible.State.SHUTTING_DOWN; |
| import static org.apache.cassandra.utils.Clock.Global.nanoTime; |
| import static org.apache.cassandra.utils.concurrent.Condition.newOneTimeCondition; |
| |
| public class InfiniteLoopExecutor implements Interruptible |
| { |
| private static final Logger logger = LoggerFactory.getLogger(InfiniteLoopExecutor.class); |
| |
| @Shared(scope = Shared.Scope.SIMULATION) |
| public enum InternalState { SHUTTING_DOWN_NOW, TERMINATED } |
| |
| @Shared(scope = Shared.Scope.SIMULATION) |
| public enum SimulatorSafe { SAFE, UNSAFE } |
| |
| @Shared(scope = Shared.Scope.SIMULATION) |
| public enum Daemon { DAEMON, NON_DAEMON } |
| |
| @Shared(scope = Shared.Scope.SIMULATION) |
| public enum Interrupts { SYNCHRONIZED, UNSYNCHRONIZED } |
| |
| private static final AtomicReferenceFieldUpdater<InfiniteLoopExecutor, Object> stateUpdater = AtomicReferenceFieldUpdater.newUpdater(InfiniteLoopExecutor.class, Object.class, "state"); |
| private final Thread thread; |
| private final Task task; |
| private volatile Object state = NORMAL; |
| private final Consumer<Thread> interruptHandler; |
| private final Condition isTerminated = newOneTimeCondition(); |
| |
| public InfiniteLoopExecutor(String name, Task task, Daemon daemon) |
| { |
| this(ExecutorFactory.Global.executorFactory(), name, task, daemon, UNSYNCHRONIZED); |
| } |
| |
| public InfiniteLoopExecutor(ExecutorFactory factory, String name, Task task, Daemon daemon) |
| { |
| this(factory, name, task, daemon, UNSYNCHRONIZED); |
| } |
| |
| public InfiniteLoopExecutor(ExecutorFactory factory, String name, Task task, Daemon daemon, Interrupts interrupts) |
| { |
| this.task = task; |
| this.thread = factory.startThread(name, this::loop, daemon); |
| this.interruptHandler = interrupts == SYNCHRONIZED |
| ? interruptHandler(task) |
| : Thread::interrupt; |
| } |
| |
| public InfiniteLoopExecutor(BiFunction<String, Runnable, Thread> threadStarter, String name, Task task, Interrupts interrupts) |
| { |
| this.task = task; |
| this.thread = threadStarter.apply(name, this::loop); |
| this.interruptHandler = interrupts == SYNCHRONIZED |
| ? interruptHandler(task) |
| : Thread::interrupt; |
| } |
| |
| private static Consumer<Thread> interruptHandler(final Object monitor) |
| { |
| return thread -> { |
| synchronized (monitor) |
| { |
| thread.interrupt(); |
| } |
| }; |
| } |
| |
| |
| private void loop() |
| { |
| boolean interrupted = false; |
| try |
| { |
| while (true) |
| { |
| try |
| { |
| Object cur = state; |
| if (cur == SHUTTING_DOWN_NOW) break; |
| |
| interrupted |= Thread.interrupted(); |
| if (cur == NORMAL && interrupted) cur = INTERRUPTED; |
| task.run((State) cur); |
| |
| interrupted = false; |
| if (cur == SHUTTING_DOWN) break; |
| } |
| catch (TerminateException ignore) |
| { |
| break; |
| } |
| catch (UncheckedInterruptedException | InterruptedException ignore) |
| { |
| interrupted = true; |
| } |
| catch (Throwable t) |
| { |
| logger.error("Exception thrown by runnable, continuing with loop", t); |
| } |
| } |
| } |
| finally |
| { |
| state = TERMINATED; |
| isTerminated.signal(); |
| } |
| } |
| |
| public void interrupt() |
| { |
| interruptHandler.accept(thread); |
| } |
| |
| public void shutdown() |
| { |
| stateUpdater.updateAndGet(this, cur -> cur != TERMINATED && cur != SHUTTING_DOWN_NOW ? SHUTTING_DOWN : cur); |
| interruptHandler.accept(thread); |
| } |
| |
| public Object shutdownNow() |
| { |
| stateUpdater.updateAndGet(this, cur -> cur != TERMINATED ? SHUTTING_DOWN_NOW : TERMINATED); |
| interruptHandler.accept(thread); |
| return null; |
| } |
| |
| @Override |
| public boolean isTerminated() |
| { |
| return state == TERMINATED; |
| } |
| |
| public boolean awaitTermination(long time, TimeUnit unit) throws InterruptedException |
| { |
| if (isTerminated()) |
| return true; |
| |
| long deadlineNanos = nanoTime() + unit.toNanos(time); |
| isTerminated.awaitUntil(deadlineNanos); |
| return isTerminated(); |
| } |
| |
| @VisibleForTesting |
| public boolean isAlive() |
| { |
| return this.thread.isAlive(); |
| } |
| } |