maven2-plugins/myfaces-javascript-plugin/src/main/java/org/apache/myfaces/buildtools/maven2/plugin/javascript/jmt/compress/YahooUICompressor.java

/*
 *  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.
 */
package org.apache.myfaces.buildtools.maven2.plugin.javascript.jmt.compress;

import java.io.File;
import java.io.FileReader;
import java.io.FileWriter;

import org.codehaus.plexus.util.IOUtil;
import org.mozilla.javascript.ErrorReporter;
import org.mozilla.javascript.EvaluatorException;

import com.yahoo.platform.yui.compressor.JavaScriptCompressor;

/**
 * A JS compressor that uses Dojo modified Rhino engine to compress the script.
 * The resulting compressed-js is garanteed to be functionaly equivalent as this
 * is the internal view of the rhino context.
 * 
 * @author <a href="mailto:nicolas@apache.org">nicolas De Loof</a>
 */
public class YahooUICompressor
    implements JSCompressor
{
    /**
     * {@inheritDoc}
     * 
     * @see org.apache.myfaces.buildtools.maven2.plugin.javascript.jmt.compress.mojo.javascript.compress.JSCompressor#compress(java.io.File,
     * java.io.File, int, int)
     */
    public void compress( final File input, File compressed, int level, int language )
        throws CompressionException
    {
        FileWriter out = null;
        try
        {
            JavaScriptCompressor compressor =
                new JavaScriptCompressor( new FileReader( input ), new ErrorReporter()
                {

                    public void warning( String message, String sourceName, int line,
                                         String lineSource, int lineOffset )
                    {
                        if ( line < 0 )
                        {
                            System.err.println( "\n[WARNING] " + message );
                        }
                        else
                        {
                            System.err.println( "\n" + line + ':' + lineOffset + ':' + message );
                        }
                    }

                    public void error( String message, String sourceName, int line,
                                       String lineSource, int lineOffset )
                    {
                        if ( line < 0 )
                        {
                            System.err.println( "\n[ERROR] " + message );
                        }
                        else
                        {
                            System.err.println( "\n" + line + ':' + lineOffset + ':' + message );
                        }
                    }

                    public EvaluatorException runtimeError( String message, String sourceName,
                                                            int line, String lineSource,
                                                            int lineOffset )
                    {
                        error( message, sourceName, line, lineSource, lineOffset );
                        return new EvaluatorException( message );
                    }
                } );

            int linebreakpos = level < 4 ? -1 : 80;
            boolean munge = level < 3;
            boolean preserveAllSemiColons = level < 2;
            boolean preserveStringLiterals = level < 1;

            out = new FileWriter( compressed );
            compressor.compress( out, linebreakpos, munge, true, preserveAllSemiColons,
                preserveStringLiterals );
        }
        catch ( Exception e )
        {
            throw new CompressionException( "Failed to create compressed file", e, input );
        }
        finally
        {
            IOUtil.close( out );
        }
    }
}