Tomcat example source code file (JIoEndpoint.java)
The Tomcat JIoEndpoint.java source code/*
* 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.net;
import java.io.IOException;
import java.net.BindException;
import java.net.InetAddress;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.concurrent.Executor;
import org.apache.juli.logging.Log;
import org.apache.juli.logging.LogFactory;
import org.apache.tomcat.util.res.StringManager;
/**
* Handle incoming TCP connections.
*
* This class implement a simple server model: one listener thread accepts on a socket and
* creates a new worker thread for each incoming connection.
*
* More advanced Endpoints will reuse the threads, use queues, etc.
*
* @author James Duncan Davidson
* @author Jason Hunter
* @author James Todd
* @author Costin Manolache
* @author Gal Shachor
* @author Yoav Shapira
* @author Remy Maucherat
*/
public class JIoEndpoint {
// -------------------------------------------------------------- Constants
protected static Log log = LogFactory.getLog(JIoEndpoint.class);
protected StringManager sm =
StringManager.getManager("org.apache.tomcat.util.net.res");
/**
* The Request attribute key for the cipher suite.
*/
public static final String CIPHER_SUITE_KEY = "javax.servlet.request.cipher_suite";
/**
* The Request attribute key for the key size.
*/
public static final String KEY_SIZE_KEY = "javax.servlet.request.key_size";
/**
* The Request attribute key for the client certificate chain.
*/
public static final String CERTIFICATE_KEY = "javax.servlet.request.X509Certificate";
/**
* The Request attribute key for the session id.
* This one is a Tomcat extension to the Servlet spec.
*/
public static final String SESSION_ID_KEY = "javax.servlet.request.ssl_session";
// ----------------------------------------------------------------- Fields
/**
* Available workers.
*/
protected WorkerStack workers = null;
/**
* Running state of the endpoint.
*/
protected volatile boolean running = false;
/**
* Will be set to true whenever the endpoint is paused.
*/
protected volatile boolean paused = false;
/**
* Track the initialization state of the endpoint.
*/
protected boolean initialized = false;
/**
* 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;
/**
* Associated server socket.
*/
protected ServerSocket serverSocket = null;
// ------------------------------------------------------------- Properties
/**
* Acceptor thread count.
*/
protected int acceptorThreadCount = 0;
public void setAcceptorThreadCount(int acceptorThreadCount) { this.acceptorThreadCount = acceptorThreadCount; }
public int getAcceptorThreadCount() { return acceptorThreadCount; }
/**
* External Executor based thread pool.
*/
protected Executor executor = null;
public void setExecutor(Executor executor) { this.executor = executor; }
public Executor getExecutor() { return executor; }
/**
* Maximum amount of worker threads.
*/
protected int maxThreads = 40;
public void setMaxThreads(int maxThreads) { this.maxThreads = maxThreads; }
public int getMaxThreads() { return maxThreads; }
/**
* Priority of the acceptor and poller threads.
*/
protected int threadPriority = Thread.NORM_PRIORITY;
public void setThreadPriority(int threadPriority) { this.threadPriority = threadPriority; }
public int getThreadPriority() { return threadPriority; }
/**
* Server socket port.
*/
protected int port;
public int getPort() { return port; }
public void setPort(int port ) { this.port=port; }
/**
* Address for the server socket.
*/
protected InetAddress address;
public InetAddress getAddress() { return address; }
public void setAddress(InetAddress address) { this.address = address; }
/**
* Handling of accepted sockets.
*/
protected Handler handler = null;
public void setHandler(Handler handler ) { this.handler = handler; }
public Handler getHandler() { return handler; }
/**
* Allows the server developer to specify the backlog that
* should be used for server sockets. By default, this value
* is 100.
*/
protected int backlog = 100;
public void setBacklog(int backlog) { if (backlog > 0) this.backlog = backlog; }
public int getBacklog() { return backlog; }
/**
* Socket TCP no delay.
*/
protected boolean tcpNoDelay = false;
public boolean getTcpNoDelay() { return tcpNoDelay; }
public void setTcpNoDelay(boolean tcpNoDelay) { this.tcpNoDelay = tcpNoDelay; }
/**
* Socket linger.
*/
protected int soLinger = 100;
public int getSoLinger() { return soLinger; }
public void setSoLinger(int soLinger) { this.soLinger = soLinger; }
/**
* Socket timeout.
*/
protected int soTimeout = -1;
public int getSoTimeout() { return soTimeout; }
public void setSoTimeout(int soTimeout) { this.soTimeout = soTimeout; }
/**
* The default is true - the created threads will be
* in daemon mode. If set to false, the control thread
* will not be daemon - and will keep the process alive.
*/
protected boolean daemon = true;
public void setDaemon(boolean b) { daemon = b; }
public boolean getDaemon() { return daemon; }
/**
* 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; }
/**
* Server socket factory.
*/
protected ServerSocketFactory serverSocketFactory = null;
public void setServerSocketFactory(ServerSocketFactory factory) { this.serverSocketFactory = factory; }
public ServerSocketFactory getServerSocketFactory() { return serverSocketFactory; }
public boolean isRunning() {
return running;
}
public boolean isPaused() {
return paused;
}
public int getCurrentThreadCount() {
return curThreads;
}
public int getCurrentThreadsBusy() {
return workers!=null?curThreads - workers.size():0;
}
// ------------------------------------------------ Handler Inner Interface
/**
* Bare bones interface used for socket processing. Per thread data is to be
* stored in the ThreadWithAttributes extra folders, or alternately in
* thread local fields.
*/
public interface Handler {
public boolean process(Socket socket);
}
// --------------------------------------------------- Acceptor Inner Class
/**
* Server socket acceptor thread.
*/
protected class Acceptor implements Runnable {
/**
* The background thread that listens for incoming TCP/IP connections and
* hands them off to an appropriate processor.
*/
public void run() {
// Loop until we receive a shutdown command
while (running) {
// Loop if endpoint is paused
while (paused) {
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
// Ignore
}
}
// Accept the next incoming connection from the server socket
try {
Socket socket = serverSocketFactory.acceptSocket(serverSocket);
serverSocketFactory.initSocket(socket);
// Hand this socket off to an appropriate processor
if (!processSocket(socket)) {
// Close socket right away
try {
socket.close();
} catch (IOException e) {
// Ignore
}
}
}catch ( IOException x ) {
if ( running ) log.error(sm.getString("endpoint.accept.fail"), x);
} catch (Throwable t) {
log.error(sm.getString("endpoint.accept.fail"), t);
}
// The processor will recycle itself when it finishes
}
}
}
// ------------------------------------------- SocketProcessor Inner Class
/**
* This class is the equivalent of the Worker, but will simply use in an
* external Executor thread pool.
*/
protected class SocketProcessor implements Runnable {
protected Socket socket = null;
public SocketProcessor(Socket socket) {
this.socket = socket;
}
public void run() {
// Process the request from this socket
if (!setSocketOptions(socket) || !handler.process(socket)) {
// Close socket
try {
socket.close();
} catch (IOException e) {
}
}
// Finish up this request
socket = null;
}
}
// ----------------------------------------------------- Worker Inner Class
protected class Worker implements Runnable {
protected Thread thread = null;
protected boolean available = false;
protected Socket socket = null;
/**
* Process an incoming TCP/IP connection on the specified socket. Any
* exception that occurs during processing must be logged and swallowed.
* <b>NOTE: 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(Socket socket) {
// 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.socket = socket;
available = true;
notifyAll();
}
/**
* Await a newly assigned Socket from our Connector, or <code>null
* if we are supposed to shut down.
*/
private synchronized Socket 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
Socket socket = this.socket;
available = false;
notifyAll();
return (socket);
}
/**
* 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
Socket socket = await();
if (socket == null)
continue;
// Process the request from this socket
if (!setSocketOptions(socket) || !handler.process(socket)) {
// Close socket
try {
socket.close();
} catch (IOException e) {
}
}
// Finish up this request
socket = null;
recycleWorkerThread(this);
}
}
/**
* Start the background processing thread.
*/
public void start() {
thread = new Thread(this);
thread.setName(getName() + "-" + (++curThreads));
thread.setDaemon(true);
thread.start();
}
}
// -------------------- Public methods --------------------
public void init()
throws Exception {
if (initialized)
return;
// Initialize thread count defaults for acceptor
if (acceptorThreadCount == 0) {
acceptorThreadCount = 1;
}
if (serverSocketFactory == null) {
serverSocketFactory = ServerSocketFactory.getDefault();
}
if (serverSocket == null) {
try {
if (address == null) {
serverSocket = serverSocketFactory.createSocket(port, backlog);
} else {
serverSocket = serverSocketFactory.createSocket(port, backlog, address);
}
} catch (BindException be) {
throw new BindException(be.getMessage() + ":" + port);
}
}
//if( serverTimeout >= 0 )
// serverSocket.setSoTimeout( serverTimeout );
initialized = true;
}
public void start()
throws Exception {
// Initialize socket if not done before
if (!initialized) {
init();
}
if (!running) {
running = true;
paused = false;
// Create worker collection
if (executor == null) {
workers = new WorkerStack(maxThreads);
}
// Start acceptor threads
for (int i = 0; i < acceptorThreadCount; i++) {
Thread acceptorThread = new Thread(new Acceptor(), getName() + "-Acceptor-" + i);
acceptorThread.setPriority(threadPriority);
acceptorThread.setDaemon(daemon);
acceptorThread.start();
}
}
}
public void pause() {
if (running && !paused) {
paused = true;
unlockAccept();
}
}
public void resume() {
if (running) {
paused = false;
}
}
public void stop() {
if (running) {
running = false;
unlockAccept();
}
}
/**
* Deallocate APR memory pools, and close server socket.
*/
public void destroy() throws Exception {
if (running) {
stop();
}
if (serverSocket != null) {
try {
if (serverSocket != null)
serverSocket.close();
} catch (Exception e) {
log.error(sm.getString("endpoint.err.close"), e);
}
serverSocket = null;
}
initialized = false ;
}
/**
* Unlock the accept by using a local connection.
*/
protected void unlockAccept() {
Socket s = null;
try {
// Need to create a connection to unlock the accept();
if (address == null) {
s = new Socket(InetAddress.getByName("localhost").getHostAddress(), port);
} else {
s = new Socket(address, port);
// setting soLinger to a small value will help shutdown the
// connection quicker
s.setSoLinger(true, 0);
}
} catch (Exception e) {
if (log.isDebugEnabled()) {
log.debug(sm.getString("endpoint.debug.unlock", "" + port), e);
}
} finally {
if (s != null) {
try {
s.close();
} catch (Exception e) {
// Ignore
}
}
}
}
/**
* Set the options for the current socket.
*/
protected boolean setSocketOptions(Socket socket) {
// Process the connection
int step = 1;
try {
// 1: Set socket options: timeout, linger, etc
if (soLinger >= 0) {
socket.setSoLinger(true, soLinger);
}
if (tcpNoDelay) {
socket.setTcpNoDelay(tcpNoDelay);
}
if (soTimeout > 0) {
socket.setSoTimeout(soTimeout);
}
// 2: SSL handshake
step = 2;
serverSocketFactory.handshake(socket);
} catch (Throwable t) {
if (log.isDebugEnabled()) {
if (step == 2) {
log.debug(sm.getString("endpoint.err.handshake"), t);
} else {
log.debug(sm.getString("endpoint.err.unexpected"), t);
}
}
// Tell to close the socket
return false;
}
return true;
}
/**
* 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 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();
}
}
/**
* Process given socket.
*/
protected boolean processSocket(Socket socket) {
try {
if (executor == null) {
getWorkerThread().assign(socket);
} else {
executor.execute(new SocketProcessor(socket));
}
} catch (Throwable t) {
// This means we got an OOM or similar creating a thread, or that
// the pool and its queue are full
log.error(sm.getString("endpoint.process.fail"), t);
return false;
}
return true;
}
// ------------------------------------------------- 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);
}
}
}
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