MINA源码分析----日志过滤器 LoggingFilter

该类继承自IoFilterAdapter，主要完成两件事

1、记录事件

2、再把会话事件传递到下一个过滤器中处理，

最后交给IoHandler处理

/*
 */
package org.apache.mina.filter.logging;

import org.apache.mina.core.filterchain.IoFilter;
import org.apache.mina.core.filterchain.IoFilterAdapter;
import org.apache.mina.core.session.IdleStatus;
import org.apache.mina.core.session.IoEventType;
import org.apache.mina.core.session.IoSession;
import org.apache.mina.core.write.WriteRequest;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Logs all MINA protocol events.  Each event can be
 * tuned to调整 use a different level based on the user's specific requirements.  Methods
 * are in place that allow the user to use either the get or set method for each event
 * and pass in the {@link IoEventType} and the {@link LogLevel}.
 *
 * By default, all events are logged to the {@link LogLevel#INFO} level except
 * {@link IoFilterAdapter#exceptionCaught(IoFilter.NextFilter, IoSession, Throwable)},
 * which is logged to {@link LogLevel#WARN}.

 * @org.apache.xbean.XBean
 */
public class LoggingFilter extends IoFilterAdapter {
    /** The logger name */
    private final String name;
    
    /** The logger */
    private final Logger logger;
    
    /** The log level for the exceptionCaught event. Default to WARN. */
    private LogLevel exceptionCaughtLevel = LogLevel.WARN;
    
    /** The log level for the messageSent event. Default to INFO. */
    private LogLevel messageSentLevel = LogLevel.INFO;
    
    /** The log level for the messageReceived event. Default to INFO. */
    private LogLevel messageReceivedLevel = LogLevel.INFO;
    
    /** The log level for the sessionCreated event. Default to INFO. */
    private LogLevel sessionCreatedLevel = LogLevel.INFO;
    
    /** The log level for the sessionOpened event. Default to INFO. */
    private LogLevel sessionOpenedLevel = LogLevel.INFO;
    
    /** The log level for the sessionIdle event. Default to INFO. */
    private LogLevel sessionIdleLevel = LogLevel.INFO;
    
    /** The log level for the sessionClosed event. Default to INFO. */
    private LogLevel sessionClosedLevel = LogLevel.INFO;
    
    /**
     * Default Constructor.
     */
    public LoggingFilter() {
        this(LoggingFilter.class.getName());
    }
    
    /**
     * Create a new NoopFilter using a class name
     * 
     * @param clazz the class which name will be used to create the logger
     */
    public LoggingFilter(Class<?> clazz) {
        this(clazz.getName());
    }

    /**
     * Create a new NoopFilter using a name
     * 
     * @param name the name used to create the logger. If null, will default to "NoopFilter"
     */
    public LoggingFilter(String name) {
        if (name == null) {
            this.name = LoggingFilter.class.getName();
        } else {
            this.name = name;
        }
        
        logger = LoggerFactory.getLogger(this.name);
    }

    /**
     * @return The logger's name
     */
    public String getName() {
        return name;
    }
    
    /**
     * Log if the logger and the current event log level are compatible. We log
     * a message and an exception.
     * 
     * @param eventLevel the event log level as requested by the user
     * @param message the message to log
     * @param cause the exception cause to log
     */
    private void log(LogLevel eventLevel, String message, Throwable cause) {
        switch (eventLevel) {
            case TRACE : logger.trace(message, cause); return;
            case DEBUG : logger.debug(message, cause); return;
            case INFO  : logger.info(message, cause); return;
            case WARN  : logger.warn(message, cause); return;
            case ERROR : logger.error(message, cause); return;
            default    : return;
        }
    }

    /**
     * Log if the logger and the current event log level are compatible. We log
     * a formated message and its parameters. 
     * 
     * @param eventLevel the event log level as requested by the user
     * @param message the formated message to log
     * @param param the parameter injected into the message
     */
    private void log(LogLevel eventLevel, String message, Object param) {
        switch (eventLevel) {
            case TRACE : logger.trace(message, param); return;
            case DEBUG : logger.debug(message, param); return;
            case INFO  : logger.info(message, param); return;
            case WARN  : logger.warn(message, param); return;
            case ERROR : logger.error(message, param); return;
            default    : return;
        }
    }

    /**
     * Log if the logger and the current event log level are compatible. We log
     * a simple message. 
     * 
     * @param eventLevel the event log level as requested by the user
     * @param message the message to log
     */
    private void log(LogLevel eventLevel, String message) {
        switch (eventLevel) {
            case TRACE : logger.trace(message); return;
            case DEBUG : logger.debug(message); return;
            case INFO  : logger.info(message); return;
            case WARN  : logger.warn(message); return;
            case ERROR : logger.error(message); return;
            default    : return;
        }
    }

    @Override
    public void exceptionCaught(NextFilter nextFilter, IoSession session,
            Throwable cause) throws Exception {
        log(exceptionCaughtLevel, "EXCEPTION :", cause);
        nextFilter.exceptionCaught(session, cause);
    }

    @Override
    public void messageReceived(NextFilter nextFilter, IoSession session,
            Object message) throws Exception {
        log(messageReceivedLevel, "RECEIVED: {}", message );
        nextFilter.messageReceived(session, message);
    }

    @Override
    public void messageSent(NextFilter nextFilter, IoSession session,
            WriteRequest writeRequest) throws Exception {
        log(messageSentLevel, "SENT: {}", writeRequest.getMessage() );
        nextFilter.messageSent(session, writeRequest);
    }

    @Override
    public void sessionCreated(NextFilter nextFilter, IoSession session)
            throws Exception {
        log(sessionCreatedLevel, "CREATED");
        nextFilter.sessionCreated(session);
    }

    @Override
    public void sessionOpened(NextFilter nextFilter, IoSession session)
    throws Exception {
        log(sessionOpenedLevel, "OPENED");
        nextFilter.sessionOpened(session);
    }

    @Override
    public void sessionIdle(NextFilter nextFilter, IoSession session,
            IdleStatus status) throws Exception {
        log(sessionIdleLevel, "IDLE");
        nextFilter.sessionIdle(session, status);
    }

    @Override
    public void sessionClosed(NextFilter nextFilter, IoSession session) throws Exception {
        log(sessionClosedLevel, "CLOSED");
        nextFilter.sessionClosed(session);
    }
    
    /**
     * Set the LogLevel for the ExceptionCaught event.
     * 
     * @param level The LogLevel to set
     */
    public void setExceptionCaughtLogLevel(LogLevel level) {
        exceptionCaughtLevel = level;
    }
    
    /**
     * Get the LogLevel for the ExceptionCaught event.
     * 
     * @return The LogLevel for the ExceptionCaught eventType
     */
    public LogLevel getExceptionCaughtLogLevel() {
        return exceptionCaughtLevel;
    }
    
    /**
     * Set the LogLevel for the MessageReceived event.
     * 
     * @param level The LogLevel to set
     */
    public void setMessageReceivedLogLevel(LogLevel level) {
        messageReceivedLevel = level;
    }
    
    /**
     * Get the LogLevel for the MessageReceived event.
     * 
     * @return The LogLevel for the MessageReceived eventType
     */
    public LogLevel getMessageReceivedLogLevel() {
        return messageReceivedLevel;
    }
    
    /**
     * Set the LogLevel for the MessageSent event.
     * 
     * @param level The LogLevel to set
     */
    public void setMessageSentLogLevel(LogLevel level) {
        messageSentLevel = level;
    }
    
    /**
     * Get the LogLevel for the MessageSent event.
     * 
     * @return The LogLevel for the MessageSent eventType
     */
    public LogLevel getMessageSentLogLevel() {
        return messageSentLevel;
    }
    
    /**
     * Set the LogLevel for the SessionCreated event.
     * 
     * @param level The LogLevel to set
     */
    public void setSessionCreatedLogLevel(LogLevel level) {
        sessionCreatedLevel = level;
    }
    
    /**
     * Get the LogLevel for the SessionCreated event.
     * 
     * @return The LogLevel for the SessionCreated eventType
     */
    public LogLevel getSessionCreatedLogLevel() {
        return sessionCreatedLevel;
    }
    
    /**
     * Set the LogLevel for the SessionOpened event.
     * 
     * @param level The LogLevel to set
     */
    public void setSessionOpenedLogLevel(LogLevel level) {
        sessionOpenedLevel = level;
    }
    
    /**
     * Get the LogLevel for the SessionOpened event.
     * 
     * @return The LogLevel for the SessionOpened eventType
     */
    public LogLevel getSessionOpenedLogLevel() {
        return sessionOpenedLevel;
    }
    
    /**
     * Set the LogLevel for the SessionIdle event.
     * 
     * @param level The LogLevel to set
     */
    public void setSessionIdleLogLevel(LogLevel level) {
        sessionIdleLevel = level;
    }
    
    /**
     * Get the LogLevel for the SessionIdle event.
     * 
     * @return The LogLevel for the SessionIdle eventType
     */
    public LogLevel getSessionIdleLogLevel() {
        return sessionIdleLevel;
    }
    
    /**
     * Set the LogLevel for the SessionClosed event.
     * 
     * @param level The LogLevel to set
     */
    public void setSessionClosedLogLevel(LogLevel level) {
        sessionClosedLevel = level;
    }

    /**
     * Get the LogLevel for the SessionClosed event.
     * 
     * @return The LogLevel for the SessionClosed eventType
     */
    public LogLevel getSessionClosedLogLevel() {
        return sessionClosedLevel;
    }
}