HttpConnector 与 HttpProcessor 同步控制

HttpConnector 与 HttpProcessor 同步控制

Tomcat学习 HttpConnector和HttpProcessor启动流程和线程交互

 

一些疑问

1、对于assign方法里面的：

　　this.socket = socket;

和awai方法里面的：

Socket socket = this.socket;

难于理解。

就是：为什么 await 需要使用一个本地变量(socket)而不是返回实例的 socket 变量呢？

因为这样一来，在当前 socket 被完全处理之前，实例的 socket 变量可以赋给下一个前来的 socket 。

 

 

------------HttpProcessor---------------------------

private boolean available = false;
 public HttpProcessor(HttpConnector connector, int id) {

        super();
        this.connector = connector;
        this.debug = connector.getDebug();
        this.id = id;
        this.proxyName = connector.getProxyName();
        this.proxyPort = connector.getProxyPort();
        this.request = (HttpRequestImpl) connector.createRequest();
        this.response = (HttpResponseImpl) connector.createResponse();
        this.serverPort = connector.getPort();
        this.threadName =
          "HttpProcessor[" + connector.getPort() + "][" + id + "]";

    }
 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();

        if ((debug >= 1) && (socket != null))
            log("  The incoming request has been awaited");

        return (socket);

    }
-------------------
public void run() {

        // Process requests until we receive a shutdown signal
        while (!stopped) {

            // Wait for the next socket to be assigned
            Socket socket = await();
            if (socket == null)
                continue;

            // Process the request from this socket
            process(socket);

            // Finish up this request
            request.recycle();
            response.recycle();
            connector.recycle(this);

        }

        // Tell threadStop() we have shut ourselves down successfully
        synchronized (threadSync) {
            threadSync.notifyAll();
        }

    }
----------------
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();

        if ((debug >= 1) && (socket != null))
            log(" An incoming request is being assigned");

    }

 

 

-------------------HttpConnector-------------------

run(){
// Loop until we receive a shutdown command
        while (!stopped) {

            // Accept the next incoming connection from the server socket
            Socket socket = null;
            try {
                socket = serverSocket.accept();
                if (connectionTimeout > 0)
                    socket.setSoTimeout(connectionTimeout);
            } catch (AccessControlException ace) {
                log("socket accept security exception: " + ace.getMessage());
                continue;
            } catch (IOException e) {
                if (started && !stopped)
                    log("accept: ", e);
                break;
            }

            // Hand this socket off to an appropriate processor
            HttpProcessor processor = createProcessor();
            if (processor == null) {
                try {
                    log(sm.getString("httpConnector.noProcessor"));
                    socket.close();
                } catch (IOException e) {
                    ;
                }
                continue;
            }
            processor.assign(socket);

            // The processor will recycle itself when it finishes

        }

        // Notify the threadStop() method that we have shut ourselves down
        synchronized (threadSync) {
            threadSync.notifyAll();
        }
}
  -----------------    
   private HttpProcessor createProcessor() {

        synchronized (processors) {
            if (processors.size() > 0)
                return ((HttpProcessor) processors.pop());
            if ((maxProcessors > 0) && (curProcessors < maxProcessors)) {
                return (newProcessor());
            } else {
                if (maxProcessors < 0) {
                    return (newProcessor());
                } else {
                    return (null);
                }
            }
        }

    }
------------------------
private HttpProcessor newProcessor() {

        HttpProcessor processor = new HttpProcessor(this, curProcessors++);
        if (processor instanceof Lifecycle) {
            try {
                ((Lifecycle) processor).start();
            } catch (LifecycleException e) {
                log("newProcessor", e);
                return (null);
            }
        }
        created.addElement(processor);
        return (processor);

    }

 ...

 

 

评论

1 楼 laj12347 2016-03-14  

感觉着两个原因都说的比较牵强， 第一处的await 方法中取出来的soket本来就是当前 处理器中的变量。

assign 中的wait方法，和唤醒方法可能是防止意外情况的发生。