/*
    * 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.log4j.varia;
  
  import java.io.DataInputStream;
  import java.io.DataOutputStream;
  import java.io.IOException;
  import java.io.InterruptedIOException;
  import java.net.ServerSocket;
  import java.net.Socket;
  
  import org.apache.log4j.RollingFileAppender;
  import org.apache.log4j.helpers.LogLog;
  
  /**
     This appender listens on a socket on the port specified by the
     <b>Port</b> property for a "RollOver" message. When such a message
     is received, the underlying log file is rolled over and an
     acknowledgment message is sent back to the process initiating the
     roll over.
  
     <p>This method of triggering roll over has the advantage of being
     operating system independent, fast and reliable.
  
     <p>A simple application {@link Roller} is provided to initiate the
     roll over.
  
     <p>Note that the initiator is not authenticated. Anyone can trigger
     a rollover. In production environments, it is recommended that you
     add some form of protection to prevent undesired rollovers.
  
  
     @author Ceki G&uuml;lc&uuml;
     @since version 0.9.0 */
  public class ExternallyRolledFileAppender extends RollingFileAppender {
  
    /**
       The string constant sent to initiate a roll over.   Current value of
       this string constant is <b>RollOver</b>.
    */
    static final public String ROLL_OVER = "RollOver";
  
    /**
       The string constant sent to acknowledge a roll over.   Current value of
        this string constant is <b>OK</b>.
    */
    static final public String OK = "OK";
  
    int port = 0;
    HUP hup;
  
    /**
       The default constructor does nothing but calls its super-class
       constructor.  */
    public
    ExternallyRolledFileAppender() {
    }
  
    /**
       The <b>Port</b> [roperty is used for setting the port for
       listening to external roll over messages.
    */
    public
    void setPort(int port) {
      this.port = port;
    }
  
    /**
       Returns value of the <b>Port</b> option.
     */
    public
    int getPort() {
      return port;
    }
  
    /**
       Start listening on the port specified by a preceding call to
       {@link #setPort}.  */
    public
    void activateOptions() {
      super.activateOptions();
      if(port != 0) {
        if(hup != null) {
  	hup.interrupt();
       }
       hup = new HUP(this, port);
       hup.setDaemon(true);
       hup.start();
     }
   }
 }
 
 
 class HUP extends Thread {
 
   int port;
   ExternallyRolledFileAppender er;
 
   HUP(ExternallyRolledFileAppender er, int port) {
     this.er = er;
     this.port = port;
   }
 
   public
   void run() {
     while(!isInterrupted()) {
       try {
 	ServerSocket serverSocket = new ServerSocket(port);
 	while(true) {
 	  Socket socket = serverSocket.accept();
 	  LogLog.debug("Connected to client at " + socket.getInetAddress());
 	  new Thread(new HUPNode(socket, er), "ExternallyRolledFileAppender-HUP").start();
 	}
       } catch(InterruptedIOException e) {
         Thread.currentThread().interrupt();
 	    e.printStackTrace();
       } catch(IOException e) {
 	    e.printStackTrace();
       } catch(RuntimeException e) {
 	    e.printStackTrace();
       }
     }
   }
 }
 
 class HUPNode implements Runnable {
 
   Socket socket;
   DataInputStream dis;
   DataOutputStream dos;
   ExternallyRolledFileAppender er;
 
   public
   HUPNode(Socket socket, ExternallyRolledFileAppender er) {
     this.socket = socket;
     this.er = er;
     try {
       dis = new DataInputStream(socket.getInputStream());
       dos = new DataOutputStream(socket.getOutputStream());
     } catch(InterruptedIOException e) {
       Thread.currentThread().interrupt();
       e.printStackTrace();
     } catch(IOException e) {
       e.printStackTrace();
     } catch(RuntimeException e) {
       e.printStackTrace();
     }
   }
 
   public void run() {
     try {
       String line = dis.readUTF();
       LogLog.debug("Got external roll over signal.");
       if(ExternallyRolledFileAppender.ROLL_OVER.equals(line)) {
 	synchronized(er) {
 	  er.rollOver();
 	}
 	dos.writeUTF(ExternallyRolledFileAppender.OK);
       }
       else {
 	dos.writeUTF("Expecting [RollOver] string.");
       }
       dos.close();
     } catch(InterruptedIOException e) {
       Thread.currentThread().interrupt();
       LogLog.error("Unexpected exception. Exiting HUPNode.", e);
     } catch(IOException e) {
       LogLog.error("Unexpected exception. Exiting HUPNode.", e);
     } catch(RuntimeException e) {
       LogLog.error("Unexpected exception. Exiting HUPNode.", e);
     }
   }
 }