This is an automated email from the ASF dual-hosted git repository.
markt pushed a commit to branch main
in repository https://gitbox.apache.org/repos/asf/tomcat.git
commit 8bd316a226a7ca267fce12de3a6c9553a42b2d04
Author: Mark Thomas <ma...@apache.org>
AuthorDate: Wed Jul 21 16:15:00 2021 +0100
Clean up imported code
Compilation will still fail
Added ALv2 header
Fixed imports
Remove deprecated code
Add RejectedExecutionHandler interface
Fixed IDE warnings
Remove unused code
---
.../tomcat/util/threads/ThreadPoolExecutor.java | 95 +++++++++++++++++-----
1 file changed, 73 insertions(+), 22 deletions(-)
diff --git a/java/org/apache/tomcat/util/threads/ThreadPoolExecutor.java
b/java/org/apache/tomcat/util/threads/ThreadPoolExecutor.java
index de9e1a8..5193209 100644
--- a/java/org/apache/tomcat/util/threads/ThreadPoolExecutor.java
+++ b/java/org/apache/tomcat/util/threads/ThreadPoolExecutor.java
@@ -1,24 +1,49 @@
+/*
+ * 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.
+ */
/*
+ * The original version of this file carried the following notice:
+ *
* Written by Doug Lea with assistance from members of JCP JSR-166
* Expert Group and released to the public domain, as explained at
* http://creativecommons.org/publicdomain/zero/1.0/
*/
-
-package java.util.concurrent;
+package org.apache.tomcat.util.threads;
import java.util.ArrayList;
import java.util.ConcurrentModificationException;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
+import java.util.concurrent.AbstractExecutorService;
+import java.util.concurrent.BlockingQueue;
+import java.util.concurrent.Executors;
+import java.util.concurrent.Future;
+import java.util.concurrent.RejectedExecutionException;
+import java.util.concurrent.ThreadFactory;
+import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.locks.AbstractQueuedSynchronizer;
import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.ReentrantLock;
/**
- * An {@link ExecutorService} that executes each submitted task using
+ * An {@link java.util.concurrent.ExecutorService}
+ * that executes each submitted task using
* one of possibly several pooled threads, normally configured
* using {@link Executors} factory methods.
*
@@ -132,7 +157,8 @@ import java.util.concurrent.locks.ReentrantLock;
* <ol>
*
* <li><em> Direct handoffs.</em> A good default choice for a work
- * queue is a {@link SynchronousQueue} that hands off tasks to threads
+ * queue is a {@link java.util.concurrent.SynchronousQueue}
+ * that hands off tasks to threads
* without otherwise holding them. Here, an attempt to queue a task
* will fail if no threads are immediately available to run it, so a
* new thread will be constructed. This policy avoids lockups when
@@ -143,7 +169,8 @@ import java.util.concurrent.locks.ReentrantLock;
* arrive on average faster than they can be processed.
*
* <li><em> Unbounded queues.</em> Using an unbounded queue (for
- * example a {@link LinkedBlockingQueue} without a predefined
+ * example a {@link java.util.concurrent.LinkedBlockingQueue}
+ * without a predefined
* capacity) will cause new tasks to wait in the queue when all
* corePoolSize threads are busy. Thus, no more than corePoolSize
* threads will ever be created. (And the value of the maximumPoolSize
@@ -156,7 +183,8 @@ import java.util.concurrent.locks.ReentrantLock;
* average faster than they can be processed.
*
* <li><em>Bounded queues.</em> A bounded queue (for example, an
- * {@link ArrayBlockingQueue}) helps prevent resource exhaustion when
+ * {@link java.util.concurrent.ArrayBlockingQueue})
+ * helps prevent resource exhaustion when
* used with finite maximumPoolSizes, but can be more difficult to
* tune and control. Queue sizes and maximum pool sizes may be traded
* off for each other: Using large queues and small pools minimizes
@@ -366,7 +394,6 @@ public class ThreadPoolExecutor extends
AbstractExecutorService {
private static final int TERMINATED = 3 << COUNT_BITS;
// Packing and unpacking ctl
- private static int runStateOf(int c) { return c & ~COUNT_MASK; }
private static int workerCountOf(int c) { return c & COUNT_MASK; }
private static int ctlOf(int rs, int wc) { return rs | wc; }
@@ -581,10 +608,8 @@ public class ThreadPoolExecutor extends
AbstractExecutorService {
private static final long serialVersionUID = 6138294804551838833L;
/** Thread this worker is running in. Null if factory fails. */
- @SuppressWarnings("serial") // Unlikely to be serializable
final Thread thread;
/** Initial task to run. Possibly null. */
- @SuppressWarnings("serial") // Not statically typed as Serializable
Runnable firstTask;
/** Per-thread task counter */
volatile long completedTasks;
@@ -603,6 +628,7 @@ public class ThreadPoolExecutor extends
AbstractExecutorService {
}
/** Delegates main run loop to outer runWorker. */
+ @Override
public void run() {
runWorker(this);
}
@@ -612,10 +638,12 @@ public class ThreadPoolExecutor extends
AbstractExecutorService {
// The value 0 represents the unlocked state.
// The value 1 represents the locked state.
+ @Override
protected boolean isHeldExclusively() {
return getState() != 0;
}
+ @Override
protected boolean tryAcquire(int unused) {
if (compareAndSetState(0, 1)) {
setExclusiveOwnerThread(Thread.currentThread());
@@ -624,6 +652,7 @@ public class ThreadPoolExecutor extends
AbstractExecutorService {
return false;
}
+ @Override
protected boolean tryRelease(int unused) {
setExclusiveOwnerThread(null);
setState(0);
@@ -1104,6 +1133,7 @@ public class ThreadPoolExecutor extends
AbstractExecutorService {
*
* @param w the worker
*/
+ @SuppressWarnings("null") // task cannot be null
final void runWorker(Worker w) {
Thread wt = Thread.currentThread();
Runnable task = w.firstTask;
@@ -1320,6 +1350,7 @@ public class ThreadPoolExecutor extends
AbstractExecutorService {
* cannot be accepted for execution
* @throws NullPointerException if {@code command} is null
*/
+ @Override
public void execute(Runnable command) {
if (command == null) {
throw new NullPointerException();
@@ -1375,6 +1406,7 @@ public class ThreadPoolExecutor extends
AbstractExecutorService {
*
* @throws SecurityException {@inheritDoc}
*/
+ @Override
public void shutdown() {
final ReentrantLock mainLock = this.mainLock;
mainLock.lock();
@@ -1406,6 +1438,7 @@ public class ThreadPoolExecutor extends
AbstractExecutorService {
*
* @throws SecurityException {@inheritDoc}
*/
+ @Override
public List<Runnable> shutdownNow() {
List<Runnable> tasks;
final ReentrantLock mainLock = this.mainLock;
@@ -1422,6 +1455,7 @@ public class ThreadPoolExecutor extends
AbstractExecutorService {
return tasks;
}
+ @Override
public boolean isShutdown() {
return runStateAtLeast(ctl.get(), SHUTDOWN);
}
@@ -1447,10 +1481,12 @@ public class ThreadPoolExecutor extends
AbstractExecutorService {
return runStateAtLeast(c, SHUTDOWN) && runStateLessThan(c, TERMINATED);
}
+ @Override
public boolean isTerminated() {
return runStateAtLeast(ctl.get(), TERMINATED);
}
+ @Override
public boolean awaitTermination(long timeout, TimeUnit unit)
throws InterruptedException {
long nanos = unit.toNanos(timeout);
@@ -1469,18 +1505,6 @@ public class ThreadPoolExecutor extends
AbstractExecutorService {
}
}
- // Override without "throws Throwable" for compatibility with subclasses
- // whose finalize method invokes super.finalize() (as is recommended).
- // Before JDK 11, finalize() had a non-empty method body.
-
- /**
- * @implNote Previous versions of this class had a finalize method
- * that shut down this executor, but in this version, finalize
- * does nothing.
- */
- @Deprecated(since="9")
- protected void finalize() {}
-
/**
* Sets the thread factory used to create new threads.
*
@@ -1923,6 +1947,7 @@ public class ThreadPoolExecutor extends
AbstractExecutorService {
*
* @return a string identifying this pool, as well as its state
*/
+ @Override
public String toString() {
long ncompleted;
int nworkers, nactive;
@@ -1985,7 +2010,8 @@ public class ThreadPoolExecutor extends
AbstractExecutorService {
* beginning of this method.
*
* <p><b>Note:</b> When actions are enclosed in tasks (such as
- * {@link FutureTask}) either explicitly or via methods such as
+ * {@link java.util.concurrent.FutureTask})
+ * either explicitly or via methods such as
* {@code submit}, these task objects catch and maintain
* computational exceptions, and so they do not cause abrupt
* termination, and the internal exceptions are <em>not</em>
@@ -2053,6 +2079,7 @@ public class ThreadPoolExecutor extends
AbstractExecutorService {
* @param r the runnable task requested to be executed
* @param e the executor attempting to execute this task
*/
+ @Override
public void rejectedExecution(Runnable r, ThreadPoolExecutor e) {
if (!e.isShutdown()) {
r.run();
@@ -2080,6 +2107,7 @@ public class ThreadPoolExecutor extends
AbstractExecutorService {
* @param e the executor attempting to execute this task
* @throws RejectedExecutionException always
*/
+ @Override
public void rejectedExecution(Runnable r, ThreadPoolExecutor e) {
throw new RejectedExecutionException("Task " + r.toString() +
" rejected from " +
@@ -2103,6 +2131,7 @@ public class ThreadPoolExecutor extends
AbstractExecutorService {
* @param r the runnable task requested to be executed
* @param e the executor attempting to execute this task
*/
+ @Override
public void rejectedExecution(Runnable r, ThreadPoolExecutor e) {
}
}
@@ -2140,6 +2169,7 @@ public class ThreadPoolExecutor extends
AbstractExecutorService {
* @param r the runnable task requested to be executed
* @param e the executor attempting to execute this task
*/
+ @Override
public void rejectedExecution(Runnable r, ThreadPoolExecutor e) {
if (!e.isShutdown()) {
e.getQueue().poll();
@@ -2147,4 +2177,25 @@ public class ThreadPoolExecutor extends
AbstractExecutorService {
}
}
}
+
+
+ public interface RejectedExecutionHandler {
+
+ /**
+ * Method that may be invoked by a {@link ThreadPoolExecutor} when
+ * {@link ThreadPoolExecutor#execute execute} cannot accept a
+ * task. This may occur when no more threads or queue slots are
+ * available because their bounds would be exceeded, or upon
+ * shutdown of the Executor.
+ *
+ * <p>In the absence of other alternatives, the method may throw
+ * an unchecked {@link RejectedExecutionException}, which will be
+ * propagated to the caller of {@code execute}.
+ *
+ * @param r the runnable task requested to be executed
+ * @param executor the executor attempting to execute this task
+ * @throws RejectedExecutionException if there is no remedy
+ */
+ void rejectedExecution(Runnable r, ThreadPoolExecutor executor);
+ }
}
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