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Logger.javaAPI DocGlassfish v2 API6917Fri May 04 22:31:52 BST 2007org.apache.catalina

Logger.java


/*
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 * 
 * Copyright 1997-2007 Sun Microsystems, Inc. All rights reserved.
 * 
 * Portions Copyright Apache Software Foundation.
 * 
 * The contents of this file are subject to the terms of either the GNU
 * General Public License Version 2 only ("GPL") or the Common Development
 * and Distribution License("CDDL") (collectively, the "License").  You
 * may not use this file except in compliance with the License. You can obtain
 * a copy of the License at https://glassfish.dev.java.net/public/CDDL+GPL.html
 * or glassfish/bootstrap/legal/LICENSE.txt.  See the License for the specific
 * language governing permissions and limitations under the License.
 * 
 * When distributing the software, include this License Header Notice in each
 * file and include the License file at glassfish/bootstrap/legal/LICENSE.txt.
 * Sun designates this particular file as subject to the "Classpath" exception
 * as provided by Sun in the GPL Version 2 section of the License file that
 * accompanied this code.  If applicable, add the following below the License
 * Header, with the fields enclosed by brackets [] replaced by your own
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 * elects to include this software in this distribution under the [CDDL or GPL
 * Version 2] license."  If you don't indicate a single choice of license, a
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 */


package org.apache.catalina;


import java.beans.PropertyChangeListener;


/**
 * A <b>Logger</b> is a generic interface for the message and exception
 * logging methods of the ServletContext interface.  Loggers can be
 * attached at any Container level, but will typically only be attached
 * to a Context, or higher level, Container.
 *
 * @author Craig R. McClanahan
 * @version $Revision: 1.3 $ $Date: 2007/05/05 05:31:51 $
 */

public interface Logger {


    // ----------------------------------------------------- Manifest Constants


    /**
     * Verbosity level constants for log messages that may be filtered
     * by the underlying logger.
     */

    public static final int FATAL = Integer.MIN_VALUE;

    public static final int ERROR = 1;

    public static final int WARNING = 2;

    public static final int INFORMATION = 3;

    public static final int DEBUG = 4;


    // ------------------------------------------------------------- Properties


    /**
     * Return the Container with which this Logger has been associated.
     */
    public Container getContainer();


    /**
     * Set the Container with which this Logger has been associated.
     *
     * @param container The associated Container
     */
    public void setContainer(Container container);


    /**
     * Return descriptive information about this Logger implementation and
     * the corresponding version number, in the format
     * <code><description>/<version></code>.
     */
    public String getInfo();


    /**
     * Return the verbosity level of this logger.  Messages logged with a
     * higher verbosity than this level will be silently ignored.
     */
    public int getVerbosity();


    /**
     * Set the verbosity level of this logger.  Messages logged with a
     * higher verbosity than this level will be silently ignored.
     *
     * @param verbosity The new verbosity level
     */
    public void setVerbosity(int verbosity);


    // --------------------------------------------------------- Public Methods


    /**
     * Add a property change listener to this component.
     *
     * @param listener The listener to add
     */
    public void addPropertyChangeListener(PropertyChangeListener listener);


    /**
     * Writes the specified message to a servlet log file, usually an event
     * log.  The name and type of the servlet log is specific to the
     * servlet container.  This message will be logged unconditionally.
     *
     * @param message A <code>String</code> specifying the message to be
     *  written to the log file
     */
    public void log(String message);


    /**
     * Writes the specified exception, and message, to a servlet log file.
     * The implementation of this method should call
     * <code>log(msg, exception)</code> instead.  This method is deprecated
     * in the ServletContext interface, but not deprecated here to avoid
     * many useless compiler warnings.  This message will be logged
     * unconditionally.
     *
     * @param exception An <code>Exception</code> to be reported
     * @param msg The associated message string
     */
    public void log(Exception exception, String msg);


    /**
     * Writes an explanatory message and a stack trace for a given
     * <code>Throwable</code> exception to the servlet log file.  The name
     * and type of the servlet log file is specific to the servlet container,
     * usually an event log.  This message will be logged unconditionally.
     *
     * @param message A <code>String</code> that describes the error or
     *  exception
     * @param throwable The <code>Throwable</code> error or exception
     */
    public void log(String message, Throwable throwable);


    /**
     * Writes the specified message to the servlet log file, usually an event
     * log, if the logger is set to a verbosity level equal to or higher than
     * the specified value for this message.
     *
     * @param message A <code>String</code> specifying the message to be
     *  written to the log file
     * @param verbosity Verbosity level of this message
     */
    public void log(String message, int verbosity);


    /**
     * Writes the specified message and exception to the servlet log file,
     * usually an event log, if the logger is set to a verbosity level equal
     * to or higher than the specified value for this message.
     *
     * @param message A <code>String</code> that describes the error or
     *  exception
     * @param throwable The <code>Throwable</code> error or exception
     * @param verbosity Verbosity level of this message
     */
    public void log(String message, Throwable throwable, int verbosity);


    /**
     * Remove a property change listener from this component.
     *
     * @param listener The listener to remove
     */
    public void removePropertyChangeListener(PropertyChangeListener listener);


}