/*
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 2002 The Apache Software Foundation.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution, if
 *    any, must include the following acknowlegement:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowlegement may appear in the software itself,
 *    if and wherever such third-party acknowlegements normally appear.
 *
 * 4. The names "The Jakarta Project", "Velocity","DVSL", and "Apache Software
 *    Foundation" must not be used to endorse or promote products derived
 *    from this software without prior written permission. For written
 *    permission, please contact apache@apache.org.
 *
 * 5. Products derived from this software may not be called "Apache"
 *    nor may "Apache" appear in their names without prior written
 *    permission of the Apache Group.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 */

package org.apache.tools.dvsl;

import org.apache.tools.ant.Project;
import org.apache.tools.ant.Task;

import org.apache.velocity.runtime.RuntimeServices;
import org.apache.velocity.runtime.RuntimeConstants;

import org.apache.velocity.runtime.log.LogSystem;

/**
 * Implementation of a logger to output messages via an Ant Task's log
 * method.  Velocity log levels are mapped to corresponding log levels
 * defined in Ant's logging API.  The end result is messages will only
 * be output if Ant log level is high enough.
 *
 * @author    <a href="mailto:billb@progress.com">Bill Burton</a>
 * @version   $Id$
 */
public class AntLogSystem implements LogSystem
{

    // Reference to the Ant Task object that initialized the Velocity Engine.
    Task task;

    /**
     * Initialize this logger with a reference to the calling Ant Task
     *
     * @param task Ant Task to use for logging.  This must not be null.
     */
    public AntLogSystem(Task task)
    {
        this.task = task;
    }

    /**
     * Initialize the logger.
     *
     * @throws Exception if null was passed into the constructor
     */
    public void init( RuntimeServices rs ) throws Exception
    {
        if ( task == null )
        {
            throw new Exception( "PANIC: " + this.getClass().getName() +
                    " was instantiated with a null Ant Task reference");
        }
    }

    /**
     * <p>
     * Log Velocity messages through the Ant Task log method.  The mapping of logging
     * levels from Velocity to Ant is as follows:
     * </p>
     *
     * <blockquote><pre>
     * Velocity Level      --&gt;  Ant Level
     * LogSystem.DEBUG_ID  --&gt;  Project.MSG_DEBUG
     * LogSystem.INFO_ID   --&gt;  Project.MSG_VERBOSE
     * LogSystem.WARN_ID   --&gt;  Project.MSG_WARN
     * LogSystem.ERROR_ID  --&gt;  Project.MSG_ERR
     * </pre></blockquote>
     *
     * @param level    severity level
     * @param message  complete error message
     * @see   org.apache.velocity.runtime.log.LogSystem
     * @see   org.apache.tools.ant.Task#log(String, int)
     */
    public void logVelocityMessage( int level, String message )
    {
        switch ( level )
        {
            case LogSystem.WARN_ID:
                task.log( RuntimeConstants.WARN_PREFIX + message, Project.MSG_WARN );
                break;
            case LogSystem.INFO_ID:
                task.log( RuntimeConstants.INFO_PREFIX + message, Project.MSG_VERBOSE );
                break;
            case LogSystem.DEBUG_ID:
                task.log( RuntimeConstants.DEBUG_PREFIX + message, Project.MSG_DEBUG );
                break;
            case LogSystem.ERROR_ID:
                task.log( RuntimeConstants.ERROR_PREFIX + message, Project.MSG_ERR );
                break;
            default:
                task.log( message );
                break;
        }
    }
}