A list of listeners, each with an associated {@code Executor}, that - * guarantees that every {@code Runnable} that is {@linkplain #add added} will - * be executed after {@link #execute()} is called. Any {@code Runnable} added - * after the call to {@code execute} is still guaranteed to execute. There is no - * guarantee, however, that listeners will be executed in the order that they - * are added. - *
- *
Exceptions thrown by a listener will be propagated up to the executor.
- * Any exception thrown during {@code Executor.execute} (e.g., a {@code
- * RejectedExecutionException} or an exception thrown by {@linkplain
- * MoreExecutors#sameThreadExecutor inline execution}) will be caught and
- * logged.
- */
-public final class ExecutionList {
- // Logger to log exceptions caught when running runnables.
- static final Logger logger = LoggerFactory.getLogger(ExecutionList.class.getName());
-
- /**
- * The runnable, executor pairs to execute. This acts as a stack threaded through the
- * {@link RunnableExecutorPair#next} field.
- */
- private RunnableExecutorPair runnables;
-
- private boolean executed;
-
- private static final Executor DEFAULT_EXECUTOR = new ThreadPoolExecutor(1, 10, 60000L, TimeUnit.MILLISECONDS, new SynchronousQueue
- * Note: For fast, lightweight listeners that would be safe to execute in
- * any thread, consider {@link MoreExecutors#sameThreadExecutor}. For heavier
- * listeners, {@code sameThreadExecutor()} carries some caveats: First, the
- * thread that the listener runs in depends on whether the {@code
- * ExecutionList} has been executed at the time it is added. In particular,
- * listeners may run in the thread that calls {@code add}. Second, the thread
- * that calls {@link #execute} may be an internal implementation thread, such
- * as an RPC network thread, and {@code sameThreadExecutor()} listeners may
- * run in this thread. Finally, during the execution of a {@code
- * sameThreadExecutor} listener, all other registered but unexecuted
- * listeners are prevented from running, even if those listeners are to run
- * in other executors.
- */
- public void add(Runnable runnable, Executor executor) {
- // Fail fast on a null. We throw NPE here because the contract of
- // Executor states that it throws NPE on null listener, so we propagate
- // that contract up into the add method as well.
- if (runnable == null) {
- throw new NullPointerException("Runnable can not be null!");
- }
- if (executor == null) {
- logger.info("Executor for listenablefuture is null, will use default executor!");
- executor = DEFAULT_EXECUTOR;
- }
- // Lock while we check state. We must maintain the lock while adding the
- // new pair so that another thread can't run the list out from under us.
- // We only add to the list if we have not yet started execution.
- synchronized (this) {
- if (!executed) {
- runnables = new RunnableExecutorPair(runnable, executor, runnables);
- return;
- }
- }
- // Execute the runnable immediately. Because of scheduling this may end up
- // getting called before some of the previously added runnables, but we're
- // OK with that. If we want to change the contract to guarantee ordering
- // among runnables we'd have to modify the logic here to allow it.
- executeListener(runnable, executor);
- }
-
- /**
- * Runs this execution list, executing all existing pairs in the order they
- * were added. However, note that listeners added after this point may be
- * executed before those previously added, and note that the execution order
- * of all listeners is ultimately chosen by the implementations of the
- * supplied executors.
- *
- * This method is idempotent. Calling it several times in parallel is
- * semantically equivalent to calling it exactly once.
- *
- * @since 10.0 (present in 1.0 as {@code run})
- */
- public void execute() {
- // Lock while we update our state so the add method above will finish adding
- // any listeners before we start to run them.
- RunnableExecutorPair list;
- synchronized (this) {
- if (executed) {
- return;
- }
- executed = true;
- list = runnables;
- runnables = null; // allow GC to free listeners even if this stays around for a while.
- }
- // If we succeeded then list holds all the runnables we to execute. The pairs in the stack are
- // in the opposite order from how they were added so we need to reverse the list to fulfill our
- // contract.
- // This is somewhat annoying, but turns out to be very fast in practice. Alternatively, we
- // could drop the contract on the method that enforces this queue like behavior since depending
- // on it is likely to be a bug anyway.
-
- // N.B. All writes to the list and the next pointers must have happened before the above
- // synchronized block, so we can iterate the list without the lock held here.
- RunnableExecutorPair reversedList = null;
- while (list != null) {
- RunnableExecutorPair tmp = list;
- list = list.next;
- tmp.next = reversedList;
- reversedList = tmp;
- }
- while (reversedList != null) {
- executeListener(reversedList.runnable, reversedList.executor);
- reversedList = reversedList.next;
- }
- }
-
- /**
- * Submits the given runnable to the given {@link Executor} catching and logging all
- * {@linkplain RuntimeException runtime exceptions} thrown by the executor.
- */
- private static void executeListener(Runnable runnable, Executor executor) {
- try {
- executor.execute(runnable);
- } catch (RuntimeException e) {
- // Log it and keep going, bad runnable and/or executor. Don't
- // punish the other runnables if we're given a bad one. We only
- // catch RuntimeException because we want Errors to propagate up.
- logger.error("RuntimeException while executing runnable "
- + runnable + " with executor " + executor, e);
- }
- }
-
- private static final class RunnableExecutorPair {
- final Runnable runnable;
- final Executor executor;
- RunnableExecutorPair next;
-
- RunnableExecutorPair(Runnable runnable, Executor executor, RunnableExecutorPair next) {
- this.runnable = runnable;
- this.executor = executor;
- this.next = next;
- }
- }
-}
diff --git a/dubbo-common/src/test/java/org/apache/dubbo/common/concurrent/ExecutionListTest.java b/dubbo-common/src/test/java/org/apache/dubbo/common/concurrent/ExecutionListTest.java
deleted file mode 100644
index a1675aca07f..00000000000
--- a/dubbo-common/src/test/java/org/apache/dubbo/common/concurrent/ExecutionListTest.java
+++ /dev/null
@@ -1,95 +0,0 @@
-/*
- * 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.dubbo.common.concurrent;
-
-import org.junit.jupiter.api.Assertions;
-import org.junit.jupiter.api.BeforeEach;
-import org.junit.jupiter.api.Test;
-
-import java.util.concurrent.CountDownLatch;
-import java.util.concurrent.Executor;
-
-import static org.mockito.ArgumentMatchers.any;
-import static org.mockito.Mockito.doThrow;
-import static org.mockito.Mockito.mock;
-import static org.mockito.Mockito.times;
-import static org.mockito.Mockito.verify;
-
-public class ExecutionListTest {
- private ExecutionList executionList;
-
- @BeforeEach
- public void setUp() throws Exception {
- this.executionList = new ExecutionList();
- }
-
- @Test
- public void testAddNullRunnable() {
- Assertions.assertThrows(NullPointerException.class, () -> this.executionList.add(null, mock(Executor.class)));
- }
-
- @Test
- public void testAddRunnableToExecutor() {
- Executor mockedExecutor = mock(Executor.class);
-
- this.executionList.add(mock(Runnable.class), mockedExecutor);
- this.executionList.execute();
-
- verify(mockedExecutor).execute(any(Runnable.class));
- }
-
- @Test
- public void testExecuteRunnableWithDefaultExecutor() throws InterruptedException {
- final CountDownLatch countDownLatch = new CountDownLatch(1);
- this.executionList.add(countDownLatch::countDown, null);
-
- this.executionList.execute();
- countDownLatch.await();
- }
-
- @Test
- public void testExceptionForExecutor() {
- Executor mockedExecutor = mock(Executor.class);
- doThrow(new RuntimeException()).when(mockedExecutor).execute(any(Runnable.class));
-
- this.executionList.add(mock(Runnable.class), mockedExecutor);
- this.executionList.execute();
- }
-
- @Test
- public void testNotRunSameRunnableTwice() {
- Executor mockedExecutor = mock(Executor.class);
-
- this.executionList.add(mock(Runnable.class), mockedExecutor);
-
- this.executionList.execute();
- this.executionList.execute();
-
- verify(mockedExecutor).execute(any(Runnable.class));
- }
-
- @Test
- public void testRunImmediatelyAfterExecuted() {
- Executor mockedExecutor = mock(Executor.class);
-
- this.executionList.add(mock(Runnable.class), mockedExecutor);
- this.executionList.execute();
- this.executionList.add(mock(Runnable.class), mockedExecutor);
-
- verify(mockedExecutor, times(2)).execute(any(Runnable.class));
- }
-}
\ No newline at end of file
diff --git a/dubbo-common/src/test/resources/log4j.xml b/dubbo-common/src/test/resources/log4j.xml
index f5da181b5e3..acb6c4de289 100644
--- a/dubbo-common/src/test/resources/log4j.xml
+++ b/dubbo-common/src/test/resources/log4j.xml
@@ -1,18 +1,19 @@