telnetappender.h

功能非常强的写日志程序

/*
 * Copyright 2003,2004 The Apache Software Foundation.
 * 
 * Licensed 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.
 */
 
#ifndef _LOG4CXX_NET_TELNET_APPENDER_H
#define _LOG4CXX_NET_TELNET_APPENDER_H

#include <log4cxx/appenderskeleton.h>
#include <log4cxx/helpers/socket.h>
#include <log4cxx/helpers/serversocket.h>
#include <log4cxx/helpers/thread.h>
#include <vector>

namespace log4cxx
{
	namespace helpers
	{
		class SocketOutputStream;
		typedef helpers::ObjectPtrT<SocketOutputStream> SocketOutputStreamPtr;
	} 
	
	namespace net
	{
/**
<p>The TelnetAppender is a log4cxx appender that specializes in
writing to a read-only socket.  The output is provided in a
telnet-friendly way so that a log can be monitored over TCP/IP.
Clients using telnet connect to the socket and receive log data.
This is handy for remote monitoring, especially when monitoring a
servlet.

<p>Here is a list of the available configuration options:

<table border=1>
<tr>
<td align=center><b>Name</b></td>
<td align=center><b>Requirement</b></td>
<td align=center><b>Description</b></td>
<td align=center><b>Sample Value</b></td>
</tr>

<tr>
<td>Port</td>
<td>optional</td>
<td>This parameter determines the port to use for announcing log events.  The default port is 23 (telnet).</td>
<td>5875</td>
</table>
*/
        class LOG4CXX_EXPORT TelnetAppender : public AppenderSkeleton
		{
		class SocketHandler;
		friend class SocketHandler;
		private:
			static int DEFAULT_PORT;
			SocketHandler * sh;
			int port;

		public:			
			DECLARE_LOG4CXX_OBJECT(TelnetAppender)
			BEGIN_LOG4CXX_CAST_MAP()
				LOG4CXX_CAST_ENTRY(TelnetAppender)
				LOG4CXX_CAST_ENTRY_CHAIN(AppenderSkeleton)
			END_LOG4CXX_CAST_MAP()

			TelnetAppender();
			~TelnetAppender();

			/** 
			This appender requires a layout to format the text to the
			attached client(s). */
			virtual bool requiresLayout() const
				{ return true; }
			
			/** all of the options have been set, create the socket handler and
			wait for connections. */
			void activateOptions();

		    /**
		    Set options
		    */
			virtual void setOption(const String& option, const String& value);

    		/**
    		Returns value of the <b>Port</b> option.
    		*/
			int getPort() const
				{ return port; }
			
    		/**
    		The <b>Port</b> option takes a positive integer representing
    		the port where the server is waiting for connections.
    		*/
			void setPort(int port)
			{ this->port = port; }
			
			
			/** shuts down the appender. */
			void close();

		protected:
			/** Handles a log event.  For this appender, that means writing the
			message to each connected client.  */
			virtual void append(const spi::LoggingEventPtr& event) ;
			
			//---------------------------------------------------------- SocketHandler:
			
		private:
			/** The SocketHandler class is used to accept connections from
			clients.  It is threaded so that clients can connect/disconnect
			asynchronously. */
			class LOG4CXX_EXPORT SocketHandler : public helpers::Thread
			{
			private:
				bool done;
				std::vector<helpers::SocketOutputStreamPtr> writers;
				std::vector<helpers::SocketPtr> connections;
				helpers::ServerSocket serverSocket;
				std::vector<helpers::SocketPtr>::size_type MAX_CONNECTIONS;

			public:
				SocketHandler(int port);
				
				/** make sure we close all network connections when this handler
				is destroyed. */
				void finalize();
				
				/** sends a message to each of the clients in telnet-friendly output. */
				void send(const String& message);
				
				/** 
				Continually accepts client connections.  Client connections
				are refused when MAX_CONNECTIONS is reached. 
				*/
				virtual void run();

			protected:
				void print(helpers::SocketOutputStreamPtr& os, const String& sz);
			}; // class SocketHandler
		}; // class TelnetAppender
    } // namespace net
}; // namespace log4cxx

#endif // _LOG4CXX_NET_TELNET_APPENDER_H