content: /**
   * 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.activemq.transport;
  
  import java.io.IOException;
  import java.net.Socket;
  import java.util.Iterator;
  import java.util.concurrent.ConcurrentLinkedQueue;
  import java.util.concurrent.atomic.AtomicInteger;
  
  import org.apache.activemq.transport.tcp.TimeStampStream;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * This filter implements write timeouts for socket write operations.
   * When using blocking IO, the Java implementation doesn't have an explicit flag
   * to set a timeout, and can cause operations to block forever (or until the TCP stack implementation times out the retransmissions,
   * which is usually around 13-30 minutes).<br/>
   * To enable this transport, in the transport URI, simpley add<br/>
   * <code>transport.soWriteTimeout=<value in millis></code>.<br/>
   * For example (15 second timeout on write operations to the socket):</br>
   * <pre><code>
   * &lt;transportConnector
   *     name=&quot;tcp1&quot;
   *     uri=&quot;tcp://127.0.0.1:61616?transport.soTimeout=10000&amp;transport.soWriteTimeout=15000"
   * /&gt;
   * </code></pre><br/>
   * For example (enable default timeout on the socket):</br>
   * <pre><code>
   * &lt;transportConnector
   *     name=&quot;tcp1&quot;
   *     uri=&quot;tcp://127.0.0.1:61616?transport.soTimeout=10000&amp;transport.soWriteTimeout=15000"
   * /&gt;
   * </code></pre>
   * @author Filip Hanik
   *
   */
  public class WriteTimeoutFilter extends TransportFilter {
  
      private static final Logger LOG = LoggerFactory.getLogger(WriteTimeoutFilter.class);
      protected static ConcurrentLinkedQueue<WriteTimeoutFilter> writers = new ConcurrentLinkedQueue<WriteTimeoutFilter>();
      protected static AtomicInteger messageCounter = new AtomicInteger(0);
      protected static TimeoutThread timeoutThread = new TimeoutThread();
  
      protected static long sleep = 5000l;
  
      protected long writeTimeout = -1;
  
      public WriteTimeoutFilter(Transport next) {
          super(next);
      }
  
      @Override
      public void oneway(Object command) throws IOException {
          try {
              registerWrite(this);
              super.oneway(command);
          } catch (IOException x) {
              throw x;
          } finally {
              deRegisterWrite(this,false,null);
          }
      }
  
      public long getWriteTimeout() {
          return writeTimeout;
      }
  
      public void setWriteTimeout(long writeTimeout) {
          this.writeTimeout = writeTimeout;
      }
  
      public static long getSleep() {
          return sleep;
      }
  
      public static void setSleep(long sleep) {
          WriteTimeoutFilter.sleep = sleep;
      }
  
  
      protected TimeStampStream getWriter() {
          return next.narrow(TimeStampStream.class);
      }
  
      protected Socket getSocket() {
          return next.narrow(Socket.class);
      }
  
      protected static void registerWrite(WriteTimeoutFilter filter) {
          writers.add(filter);
      }
  
      protected static boolean deRegisterWrite(WriteTimeoutFilter filter, boolean fail, IOException iox) {
          boolean result = writers.remove(filter);
          if (result) {
              if (fail) {
                  String message = "Forced write timeout for:"+filter.getNext().getRemoteAddress();
                  LOG.warn(message);
                  Socket sock = filter.getSocket();
                  if (sock==null) {
                      LOG.error("Destination socket is null, unable to close socket.("+message+")");
                  } else {
                      try {
                          sock.close();
                      }catch (IOException ignore) {
                      }
                  }
              }
          }
          return result;
      }
  
      @Override
      public void start() throws Exception {
          super.start();
      }
  
      @Override
      public void stop() throws Exception {
          super.stop();
      }
  
      protected static class TimeoutThread extends Thread {
          static AtomicInteger instance = new AtomicInteger(0);
          boolean run = true;
          public TimeoutThread() {
              setName("WriteTimeoutFilter-Timeout-"+instance.incrementAndGet());
              setDaemon(true);
              setPriority(Thread.MIN_PRIORITY);
              start();
          }
  
  
          public void run() {
              while (run) {
                  boolean error = false;
                  try {
                      if (!interrupted()) {
                          Iterator<WriteTimeoutFilter> filters = writers.iterator();
                          while (run && filters.hasNext()) {
                              WriteTimeoutFilter filter = filters.next();
                              if (filter.getWriteTimeout()<=0) continue; //no timeout set
                              long writeStart = filter.getWriter().getWriteTimestamp();
                              long delta = (filter.getWriter().isWriting() && writeStart>0)?System.currentTimeMillis() - writeStart:-1;
                              if (delta>filter.getWriteTimeout()) {
                                  WriteTimeoutFilter.deRegisterWrite(filter, true,null);
                              }//if timeout
                          }//while
                      }//if interrupted
                      try {
                          Thread.sleep(getSleep());
                          error = false;
                      } catch (InterruptedException x) {
                          //do nothing
                      }
                  }catch (Throwable t) { //make sure this thread never dies
                      if (!error) { //use error flag to avoid filling up the logs
                          LOG.error("WriteTimeout thread unable validate existing sockets.",t);
                          error = true;
                      }
                  }
              }
          }
      }
  
  }
  