src/java/org/apache/velocity/runtime/log/LogDisplayWrapper.java

package org.apache.velocity.runtime.log;

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.    
 */

/**
 * This is a wrapper around a log object, that can add a prefix to log messages
 * and also turn logging on and off dynamically. It is mainly used to control the
 * logging of VelociMacro generation messages but is actually generic enough code.
 *

 * @author <a href="mailto:henning@apache.org">Henning P. Schmiedehausen</a>
 * @version $Id$
 * @since 1.5
 */
public class LogDisplayWrapper
        extends Log
{
    /** The prefix to record with every log message */
    private final String prefix;

    /** log messages only if true */
    private final boolean outputMessages;

    /** The Log object we wrap */
    private final Log log;

    /**
     * Create a new LogDisplayWrapper
     * @param log The Log object to wrap.
     * @param prefix The prefix to record with all messages.
     * @param outputMessages True when messages should actually get logged.
     */
    public LogDisplayWrapper(final Log log, final String prefix, final boolean outputMessages)
    {
        super(log.getLogChute());
        this.log = log;
        this.prefix = prefix;
        this.outputMessages = outputMessages;
    }

    /**
     * make sure that we always use the right LogChute Object
     */
    protected LogChute getLogChute()
    {
        return log.getLogChute();
    }

    /**
     * @see Log#log(int, Object)
     */
    protected void log(final int level, final Object message)
    {
    	log(outputMessages, level, message);
    }
    
    protected void log(final boolean doLogging, final int level, final Object message)
    {
        if (doLogging)
        {
            getLogChute().log(level, prefix + String.valueOf(message));
        }
    }

    /**
     * @see Log#log(int, Object, Throwable)
     */
    protected void log(final int level, final Object message, final Throwable t)
    {
    	log(outputMessages, level, message);
    }
    
    protected void log(final boolean doLogging, final int level, final Object message, final Throwable t)
    {
        if (doLogging)
        {
            getLogChute().log(level, prefix + String.valueOf(message), t);
        }
    }
    
    /**
     * Log a trace message.
     * @param doLogging Log only if this parameter is true.
     * @param message
     */
    public void trace(final boolean doLogging, final Object message)
    {
        log(doLogging, LogChute.TRACE_ID, message);
    }

    /**
     * Log a trace message and accompanying Throwable.
     * @param doLogging Log only if this parameter is true.
     * @param message
     * @param t
     */
    public void trace(final boolean doLogging, final Object message, final Throwable t)
    {
        log(doLogging, LogChute.TRACE_ID, message, t);
    }

    /**
     * Log a debug message.
     * @param doLogging Log only if this parameter is true.
     * @param message
     */
    public void debug(final boolean doLogging, final Object message)
    {
        log(doLogging, LogChute.DEBUG_ID, message);
    }

    /**
     * Log a debug message and accompanying Throwable.
     * @param doLogging Log only if this parameter is true.
     * @param message
     * @param t
     */
    public void debug(final boolean doLogging, final Object message, final Throwable t)
    {
        log(doLogging, LogChute.DEBUG_ID, message, t);
    }

    /**
     * Log an info message.
     * @param doLogging Log only if this parameter is true.
     * @param message
     */
    public void info(final boolean doLogging, final Object message)
    {
        log(doLogging, LogChute.INFO_ID, message);
    }

    /**
     * Log an info message and accompanying Throwable.
     * @param doLogging Log only if this parameter is true.
     * @param message
     * @param t
     */
    public void info(final boolean doLogging, final Object message, final Throwable t)
    {
        log(doLogging, LogChute.INFO_ID, message, t);
    }

    /**
     * Log a warning message.
     * @param doLogging Log only if this parameter is true.
     * @param message
     */
    public void warn(final boolean doLogging, final Object message)
    {
        log(doLogging, LogChute.WARN_ID, message);
    }

    /**
     * Log a warning message and accompanying Throwable.
     * @param doLogging Log only if this parameter is true.
     * @param message
     * @param t
     */
    public void warn(final boolean doLogging, final Object message, final Throwable t)
    {
        log(doLogging, LogChute.WARN_ID, message, t);
    }

    /**
     * Log an error message.
     * @param doLogging Log only if this parameter is true.
     * @param message
     */
    public void error(final boolean doLogging, final Object message)
    {
        log(doLogging, LogChute.ERROR_ID, message);
    }

    /**
     * Log an error message and accompanying Throwable.
     * @param doLogging Log only if this parameter is true.
     * @param message
     * @param t
     */
    public void error(final boolean doLogging, final Object message, final Throwable t)
    {
        log(doLogging, LogChute.ERROR_ID, message, t);
    }
}