logcategory.java

aglet的部分源码

package org.aglets.log;

/**
 *  Abstract logging system interface. Hides actual implementation of hierachal
 *  logging system.
 *
 * @author     Robert Bergstrom
 * @created    July 16, 2001
 * @version    1.0
 */
public interface LogCategory {

    
    /**
     *  Logs a message at fatal priority.
     *
     * @param  msg  Message to be logged.
     * @since       1.0
     */
    public void fatal(Object msg);
    
    /**
     *  Logs a message at error priority.
     *
     * @param  msg  Message to be logged.
     * @since       1.0
     */
    public void error(Object msg);


    /**
     *  Logs a message at error priority and passes an exception for logging.
     *
     * @param  msg  Message to be logged.
     * @param  exc  Description of Parameter
     * @since       1.0
     */
    public void error(Object msg, Exception exc);


    /**
     *  Logs a message at warn priority.
     *
     * @param  msg  Message to be logged.
     * @since       1.0
     */
    public void warn(Object msg);


    /**
     *  Logs a mesasge at info priority.
     *
     * @param  msg  Message to be logged.
     * @since       1.0
     */
    public void info(Object msg);


    /**
     *  Logs a message at debug priority.
     *
     * @param  msg  Message to be logged.
     * @since       1.0
     */
    public void debug(Object msg);
    
    /**
    *  Check whether this category is enabled for the <code>DEBUG</code>
    *  priority.
    *  
    *  <p> This function is intended to lessen the computational cost of
    *  disabled log debug statements.
    * 
    *  <p> For some <code>cat</code> Category object, when you write,
    *  <pre>
    *      cat.debug("This is entry number: " + i );
    *  </pre>
    *  
    *  <p>You incur the cost constructing the message, concatenatiion in
    *  this case, regardless of whether the message is logged or not.
    * 
    *  <p>If you are worried about speed, then you should write
    *  <pre>
    * 	 if(cat.isDebugEnabled()) { 
    * 	   cat.debug("This is entry number: " + i );
    * 	 }
    *  </pre>
    * 
    *  <p>This way you will not incur the cost of parameter
    *  construction if debugging is disabled for <code>cat</code>. On
    *  the other hand, if the <code>cat</code> is debug enabled, you
    *  will incur the cost of evaluating whether the category is debug
    *  enabled twice. Once in <code>isDebugEnabled</code> and once in
    *  the <code>debug</code>.  This is an insignificant overhead
    *  since evaluating a category takes about 1%% of the time it
    *  takes to actually log.
    * 
    *  @return boolean - <code>true</code> if this category is debug
    *  enabled, <code>false</code> otherwise.
    *   
    */
    public boolean isDebugEnabled();

}