--- /dev/null
+/*
+ * Copyright 1999-2006 The Apache Software Foundation
+ *
+ * Licensed 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.net;
+
+import java.util.concurrent.Executor;
+
+public class SimpleThreadPoolExecutor implements Executor {
+
+
+ private boolean running = true;
+
+ /**
+ * Available workers.
+ */
+ protected WorkerStack workers = null;
+
+ /**
+ * Current worker threads busy count.
+ */
+ protected int curThreadsBusy = 0;
+
+
+ /**
+ * Current worker threads count.
+ */
+ protected int curThreads = 0;
+
+
+ /**
+ * Sequence number used to generate thread names.
+ */
+ protected int sequence = 0;
+
+
+ /**
+ * Maximum amount of worker threads.
+ */
+ protected int maxThreads = 40;
+ public void setMaxThreads(int maxThreads) { this.maxThreads = maxThreads; }
+ public int getMaxThreads() { return maxThreads; }
+
+ /**
+ * Name of the thread pool, which will be used for naming child threads.
+ */
+ protected String name = "TP";
+ public void setName(String name) { this.name = name; }
+ public String getName() { return name; }
+
+ public int getCurrentThreadCount() {
+ return curThreads;
+ }
+
+ public int getCurrentThreadsBusy() {
+ return curThreads - workers.size();
+ }
+
+ public SimpleThreadPoolExecutor(String name, int maxThreads) {
+ this.name = name;
+ this.maxThreads = maxThreads;
+ workers = new WorkerStack(maxThreads);
+ }
+
+ public void execute(Runnable job){
+ getWorkerThread().assign(job);
+ }
+
+ // ----------------------------------------------------- Worker Inner Class
+
+
+ protected class Worker implements Runnable {
+
+ protected Thread thread = null;
+ protected boolean available = false;
+ protected Runnable job = null;
+
+
+ /**
+ * Process an incoming TCP/IP connection on the specified socket. Any
+ * exception that occurs during processing must be logged and swallowed.
+ * <b>NOTE</b>: This method is called from our Connector's thread. We
+ * must assign it to our own thread so that multiple simultaneous
+ * requests can be handled.
+ *
+ * @param socket TCP socket to process
+ */
+ synchronized void assign(Runnable job) {
+
+ // Wait for the Processor to get the previous Socket
+ while (available) {
+ try {
+ wait();
+ } catch (InterruptedException e) {
+ }
+ }
+
+ // Store the newly available Socket and notify our thread
+ this.job = job;
+ available = true;
+ notifyAll();
+
+ }
+
+
+ /**
+ * Await a newly assigned Socket from our Connector, or <code>null</code>
+ * if we are supposed to shut down.
+ */
+ private synchronized Runnable await() {
+
+ // Wait for the Connector to provide a new Socket
+ while (!available) {
+ try {
+ wait();
+ } catch (InterruptedException e) {
+ }
+ }
+
+ // Notify the Connector that we have received this Socket
+ Runnable job = this.job;
+ available = false;
+ notifyAll();
+
+ return (job);
+
+ }
+
+ public void shutdown(){
+ running = false;
+ }
+
+ /**
+ * The background thread that listens for incoming TCP/IP connections and
+ * hands them off to an appropriate processor.
+ */
+ public void run() {
+
+ // Process requests until we receive a shutdown signal
+ while (running) {
+
+ // Wait for the next socket to be assigned
+ Runnable job = await();
+ if (job == null)
+ continue;
+
+ job.run();
+
+ job = null;
+
+ recycleWorkerThread(this);
+ }
+
+ }
+
+
+ /**
+ * Start the background processing thread.
+ */
+ public void start() {
+ thread = new Thread(this);
+ thread.setName(getName() + "-" + (++curThreads));
+ thread.setDaemon(true);
+ thread.start();
+ }
+
+
+ }
+
+
+ /**
+ * Create (or allocate) and return an available processor for use in
+ * processing a specific HTTP request, if possible. If the maximum
+ * allowed processors have already been created and are in use, return
+ * <code>null</code> instead.
+ */
+ protected Worker createWorkerThread() {
+
+ synchronized (workers) {
+ if (workers.size() > 0) {
+ curThreadsBusy++;
+ return workers.pop();
+ }
+ if ((maxThreads > 0) && (curThreads < maxThreads)) {
+ curThreadsBusy++;
+ return (newWorkerThread());
+ } else {
+ if (maxThreads < 0) {
+ curThreadsBusy++;
+ return (newWorkerThread());
+ } else {
+ return (null);
+ }
+ }
+ }
+
+ }
+
+ /**
+ * Create and return a new processor suitable for processing HTTP
+ * requests and returning the corresponding responses.
+ */
+ protected Worker newWorkerThread() {
+
+ Worker workerThread = new Worker();
+ workerThread.start();
+ return (workerThread);
+
+ }
+
+ /**
+ * Return a new worker thread, and block while to worker is available.
+ */
+ protected Worker getWorkerThread() {
+ // Allocate a new worker thread
+ Worker workerThread = createWorkerThread();
+ while (workerThread == null) {
+ try {
+ synchronized (workers) {
+ workers.wait();
+ }
+ } catch (InterruptedException e) {
+ // Ignore
+ }
+ workerThread = createWorkerThread();
+ }
+ return workerThread;
+ }
+
+
+ /**
+ * Recycle the specified Processor so that it can be used again.
+ *
+ * @param workerThread The processor to be recycled
+ */
+ protected void recycleWorkerThread(Worker workerThread) {
+ synchronized (workers) {
+ workers.push(workerThread);
+ curThreadsBusy--;
+ workers.notify();
+ }
+ }
+
+ // ------------------------------------------------- WorkerStack Inner Class
+
+
+ public class WorkerStack {
+
+ protected Worker[] workers = null;
+ protected int end = 0;
+
+ public WorkerStack(int size) {
+ workers = new Worker[size];
+ }
+
+ /**
+ * Put the object into the queue.
+ *
+ * @param object the object to be appended to the queue (first element).
+ */
+ public void push(Worker worker) {
+ workers[end++] = worker;
+ }
+
+ /**
+ * Get the first object out of the queue. Return null if the queue
+ * is empty.
+ */
+ public Worker pop() {
+ if (end > 0) {
+ return workers[--end];
+ }
+ return null;
+ }
+
+ /**
+ * Get the first object out of the queue, Return null if the queue
+ * is empty.
+ */
+ public Worker peek() {
+ return workers[end];
+ }
+
+ /**
+ * Is the queue empty?
+ */
+ public boolean isEmpty() {
+ return (end == 0);
+ }
+
+ /**
+ * How many elements are there in this queue?
+ */
+ public int size() {
+ return (end);
+ }
+ }
+
+
+}
projects / tomcat7.0 / commitdiff