ToolFacade.java

package org.codehaus.mojo.javacc;

/*
 * 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.
 */

import org.apache.maven.plugin.MojoExecutionException;
import org.apache.maven.plugin.MojoFailureException;
import org.apache.maven.plugin.logging.Log;
import org.apache.maven.plugin.logging.SystemStreamLog;

/**
 * Provides a facade for the mojos to invoke JavaCC related tools.
 * 
 * @author Benjamin Bentmann
 * @version $Id$
 */
abstract class ToolFacade
{

    /**
     * The logger used to output diagnostic messages.
     */
    private Log log;

    /**
     * Sets the logger used to output diagnostic messages.
     * 
     * @param logger The logger used to output diagnostic messages, may be <code>null</code>.
     */
    public void setLog( Log logger )
    {
        this.log = logger;
    }

    /**
     * Gets the logger used to output diagnostic messages.
     * 
     * @return The logger used to output diagnostic messages, never <code>null</code>.
     */
    protected Log getLog()
    {
        if ( this.log == null )
        {
            this.log = new SystemStreamLog();
        }
        return this.log;
    }

    /**
     * Gets the name of the tool.
     * 
     * @return The name of the tool, never <code>null</code>.
     */
    protected String getToolName()
    {
        String name = getClass().getName();
        return name.substring( name.lastIndexOf( '.' ) + 1 );
    }

    /**
     * Runs the tool using the previously set parameters.
     * 
     * @throws MojoExecutionException If the tool could not be invoked.
     * @throws MojoFailureException If the tool reported a non-zero exit code.
     */
    public void run()
        throws MojoExecutionException, MojoFailureException
    {
        int exitCode;
        try
        {
            if ( getLog().isDebugEnabled() )
            {
                getLog().debug( "Running " + getToolName() + ": " + this );
            }
            exitCode = execute();
        }
        catch ( Exception e )
        {
            throw new MojoExecutionException( "Failed to execute " + getToolName(), e );
        }
        if ( exitCode != 0 )
        {
            throw new MojoFailureException( getToolName() + " reported exit code " + exitCode + ": " + this );
        }
    }

    /**
     * Runs the tool using the previously set parameters.
     * 
     * @return The exit code of the tool, non-zero means failure.
     * @throws Exception If the tool could not be invoked.
     */
    protected abstract int execute()
        throws Exception;

}