/**
    * Logback: the reliable, generic, fast and flexible logging framework.
    * Copyright (C) 1999-2015, QOS.ch. All rights reserved.
    *
    * This program and the accompanying materials are dual-licensed under
    * either the terms of the Eclipse Public License v1.0 as published by
    * the Eclipse Foundation
    *
    *   or (per the licensee's choosing)
   *
   * under the terms of the GNU Lesser General Public License version 2.1
   * as published by the Free Software Foundation.
   */
  package ch.qos.logback.core.net.server;
  
  import java.io.IOException;
  import java.io.Serializable;
  import java.net.InetAddress;
  import java.net.ServerSocket;
  import java.net.UnknownHostException;
  import java.util.concurrent.Executor;
  
  import javax.net.ServerSocketFactory;
  
  import ch.qos.logback.core.AppenderBase;
  import ch.qos.logback.core.net.AbstractSocketAppender;
  import ch.qos.logback.core.spi.PreSerializationTransformer;
  
  /**
   * 
   * This is the super class for module specific ServerSocketAppender
   * implementations can derive from.
   * 
   * @author Carl Harris
   */
  public abstract class AbstractServerSocketAppender<E> extends AppenderBase<E> {
  
      /**
       * Default {@link ServerSocket} backlog
       */
      public static final int DEFAULT_BACKLOG = 50;
  
      /**
       * Default queue size used for each client
       */
      public static final int DEFAULT_CLIENT_QUEUE_SIZE = 100;
  
      private int port = AbstractSocketAppender.DEFAULT_PORT;
      private int backlog = DEFAULT_BACKLOG;
      private int clientQueueSize = DEFAULT_CLIENT_QUEUE_SIZE;
  
      private String address;
  
      private ServerRunner<RemoteReceiverClient> runner;
  
      @Override
      public void start() {
          if (isStarted())
              return;
          try {
              ServerSocket socket = getServerSocketFactory().createServerSocket(getPort(), getBacklog(),
                      getInetAddress());
              ServerListener<RemoteReceiverClient> listener = createServerListener(socket);
  
              runner = createServerRunner(listener, getContext().getExecutorService());
              runner.setContext(getContext());
              getContext().getExecutorService().execute(runner);
              super.start();
          } catch (Exception ex) {
              addError("server startup error: " + ex, ex);
          }
      }
  
      protected ServerListener<RemoteReceiverClient> createServerListener(ServerSocket socket) {
          return new RemoteReceiverServerListener(socket);
      }
  
      protected ServerRunner<RemoteReceiverClient> createServerRunner(ServerListener<RemoteReceiverClient> listener,
              Executor executor) {
          return new RemoteReceiverServerRunner(listener, executor, getClientQueueSize());
      }
  
      @Override
      public void stop() {
          if (!isStarted())
              return;
          
          try {
              runner.stop();
              super.stop();
          } catch (IOException ex) {
              addError("server shutdown error: " + ex, ex);
          }
      }
  
      @Override
      protected void append(E event) {
          if (event == null)
              return;
         postProcessEvent(event);
         final Serializable serEvent = getPST().transform(event);
         runner.accept(new ClientVisitor<RemoteReceiverClient>() {
             public void visit(RemoteReceiverClient client) {
                 client.offer(serEvent);
             }
         });
     }
 
     /**
      * Postprocess an event received via {@link #append append()}.
      * 
      * @param event
      */
     protected abstract void postProcessEvent(E event);
 
     /**
      * Gets a transformer that will be used to convert a received event to a
      * {@link Serializable} form.
      * 
      * @return
      */
     protected abstract PreSerializationTransformer<E> getPST();
 
     /**
      * Gets the factory used to create {@link ServerSocket} objects.
      * <p>
      * The default implementation delegates to
      * {@link ServerSocketFactory#getDefault()}. Subclasses may override to private
      * a different socket factory implementation.
      * 
      * @return socket factory.
      */
     protected ServerSocketFactory getServerSocketFactory() throws Exception {
         return ServerSocketFactory.getDefault();
     }
 
     /**
      * Gets the local address for the listener.
      * 
      * @return an {@link InetAddress} representation of the local address.
      * @throws UnknownHostException
      */
     protected InetAddress getInetAddress() throws UnknownHostException {
         if (getAddress() == null)
             return null;
         return InetAddress.getByName(getAddress());
     }
 
     /**
      * Gets the local port for the listener.
      * 
      * @return local port
      */
     public int getPort() {
         return port;
     }
 
     /**
      * Sets the local port for the listener.
      * 
      * @param port the local port to set
      */
     public void setPort(int port) {
         this.port = port;
     }
 
     /**
      * Gets the listener queue depth.
      * <p>
      * This represents the number of connected clients whose connections have not
      * yet been accepted.
      * 
      * @return queue depth
      * @see java.net.ServerSocket
      */
     public int getBacklog() {
         return backlog;
     }
 
     /**
      * Sets the listener queue depth.
      * <p>
      * This represents the number of connected clients whose connections have not
      * yet been accepted.
      * 
      * @param backlog the queue depth to set
      * @see java.net.ServerSocket
      */
     public void setBacklog(int backlog) {
         this.backlog = backlog;
     }
 
     /**
      * Gets the local address for the listener.
      * 
      * @return a string representation of the local address
      */
     public String getAddress() {
         return address;
     }
 
     /**
      * Sets the local address for the listener.
      * 
      * @param address a host name or a string representation of an IP address
      */
     public void setAddress(String address) {
         this.address = address;
     }
 
     /**
      * Gets the event queue size used for each client connection.
      * 
      * @return queue size
      */
     public int getClientQueueSize() {
         return clientQueueSize;
     }
 
     /**
      * Sets the event queue size used for each client connection.
      * 
      * @param clientQueueSize the queue size to set
      */
     public void setClientQueueSize(int clientQueueSize) {
         this.clientQueueSize = clientQueueSize;
     }
 
 }