JTBJavaCCMojo.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 java.io.File;

import org.apache.maven.plugin.MojoExecutionException;
import org.apache.maven.plugin.MojoFailureException;

/**
 * Preprocesses ordinary grammar files (<code>*.jtb</code>) with JTB and passes the output to JavaCC in order to
 * finally generate a parser with parse tree actions.<br/><br/><strong>Note:</strong> <a
 * href="http://compilers.cs.ucla.edu/jtb/">JTB</a> requires Java 1.5 or higher. This goal will not work with earlier
 * versions of the JRE.
 * 
 * @goal jtb-javacc
 * @phase generate-sources
 * @since 2.4
 * @author Benjamin Bentmann
 * @version $Id$
 */
public class JTBJavaCCMojo
    extends AbstractJavaCCMojo
{

    /**
     * This option is short for <code>nodePackageName</code> = <code><packageName>.syntaxtree</code> and
     * <code>visitorPackageName</code> = <code><packageName>.visitor</code>. Note that this option takes
     * precedence over <code>nodePackageName</code> and <code>visitorPackageName</code> if specified.
     * 
     * @parameter expression="${package}"
     */
    private String packageName;

    /**
     * This option specifies the package for the generated AST nodes. This value may use a leading asterisk to reference
     * the package of the corresponding parser. For example, if the parser package is <code>org.apache</code> and this
     * parameter is set to <code>*.demo</code>, the tree node classes will be located in the package
     * <code>org.apache.demo</code>. Default value is <code>*.syntaxtree</code>.
     * 
     * @parameter expression="${nodePackageName}"
     */
    private String nodePackageName;

    /**
     * This option specifies the package for the generated visitors. This value may use a leading asterisk to reference
     * the package of the corresponding parser. For example, if the parser package is <code>org.apache</code> and this
     * parameter is set to <code>*.demo</code>, the visitor classes will be located in the package
     * <code>org.apache.demo</code>. Default value is <code>*.visitor</code>.
     * 
     * @parameter expression="${visitorPackageName}"
     */
    private String visitorPackageName;

    /**
     * If <code>true</code>, JTB will suppress its semantic error checking. Default value is <code>false</code>.
     * 
     * @parameter expression="${supressErrorChecking}"
     */
    private Boolean supressErrorChecking;

    /**
     * If <code>true</code>, all generated comments will be wrapped in <code><pre></code> tags so that they
     * are formatted correctly in API docs. Default value is <code>false</code>.
     * 
     * @parameter expression="${javadocFriendlyComments}"
     */
    private Boolean javadocFriendlyComments;

    /**
     * Setting this option to <code>true</code> causes JTB to generate field names that reflect the structure of the
     * tree instead of generic names like <code>f0</code>, <code>f1</code> etc. Default value is <code>false</code>.
     * 
     * @parameter expression="${descriptiveFieldNames}"
     */
    private Boolean descriptiveFieldNames;

    /**
     * The qualified name of a user-defined class from which all AST nodes will inherit. By default, AST nodes will
     * inherit from the generated class <code>Node</code>.
     * 
     * @parameter expression="${nodeParentClass}"
     */
    private String nodeParentClass;

    /**
     * If <code>true</code>, all nodes will contain fields for its parent node. Default value is <code>false</code>.
     * 
     * @parameter expression="${parentPointers}"
     */
    private Boolean parentPointers;

    /**
     * If <code>true</code>, JTB will include JavaCC "special tokens" in the AST. Default value is <code>false</code>.
     * 
     * @parameter expression="${specialTokens}"
     */
    private Boolean specialTokens;

    /**
     * If <code>true</code>, JTB will generate the following files to support the Schema programming language:
     * <ul>
     * <li>Scheme records representing the grammar.</li>
     * <li>A Scheme tree building visitor.</li>
     * </ul>
     * Default value is <code>false</code>.
     * 
     * @parameter expression="${scheme}"
     */
    private Boolean scheme;

    /**
     * If <code>true</code>, JTB will generate a syntax tree dumping visitor. Default value is <code>false</code>.
     * 
     * @parameter expression="${printer}"
     */
    private Boolean printer;

    /**
     * The directory where the JavaCC grammar files (<code>*.jtb</code>) are located. It will be recursively scanned
     * for input files to pass to JTB. The parameters <code>includes</code> and <code>excludes</code> can be used to
     * select a subset of files.
     * 
     * @parameter expression="${sourceDirectory}" default-value="${basedir}/src/main/jtb"
     */
    private File sourceDirectory;

    /**
     * The directory where the visitor and AST node files generated by JTB will be stored. The directory will be
     * registered as a compile source root of the project such that the generated files will participate in later build
     * phases like compiling and packaging.
     * 
     * @parameter expression="${interimDirectory}" default-value="${project.build.directory}/generated-sources/jtb"
     */
    private File interimDirectory;

    /**
     * The directory where the parser files generated by JavaCC will be stored. The directory will be registered as a
     * compile source root of the project such that the generated files will participate in later build phases like
     * compiling and packaging.
     * 
     * @parameter expression="${outputDirectory}" default-value="${project.build.directory}/generated-sources/javacc"
     */
    private File outputDirectory;

    /**
     * A set of Ant-like inclusion patterns used to select files from the source directory for processing. By default,
     * the patterns <code>**/*.jj</code>, <code>**/*.JJ</code>, <code>**/*.jtb</code> and
     * <code>**/*.JTB</code> are used to select grammar files.
     * 
     * @parameter
     */
    private String[] includes;

    /**
     * A set of Ant-like exclusion patterns used to prevent certain files from being processing. By default, this set is
     * empty such that no files are excluded.
     * 
     * @parameter
     */
    private String[] excludes;

    /**
     * The granularity in milliseconds of the last modification date for testing whether a grammar file needs
     * recompilation.
     * 
     * @parameter expression="${lastModGranularityMs}" default-value="0"
     */
    private int staleMillis;

    /**
     * {@inheritDoc}
     */
    protected File getSourceDirectory()
    {
        return this.sourceDirectory;
    }

    /**
     * {@inheritDoc}
     */
    protected String[] getIncludes()
    {
        if ( this.includes != null )
        {
            return this.includes;
        }
        else
        {
            return new String[] { "**/*.jj", "**/*.JJ", "**/*.jtb", "**/*.JTB" };
        }
    }

    /**
     * {@inheritDoc}
     */
    protected String[] getExcludes()
    {
        return this.excludes;
    }

    /**
     * {@inheritDoc}
     */
    protected File getOutputDirectory()
    {
        return this.outputDirectory;
    }

    /**
     * {@inheritDoc}
     */
    protected int getStaleMillis()
    {
        return this.staleMillis;
    }

    /**
     * Gets the absolute path to the directory where the interim output from JTB will be stored.
     * 
     * @return The absolute path to the directory where the interim output from JTB will be stored.
     */
    private File getInterimDirectory()
    {
        return this.interimDirectory;
    }

    /**
     * {@inheritDoc}
     */
    protected File[] getCompileSourceRoots()
    {
        return new File[] { getOutputDirectory(), getInterimDirectory() };
    }

    /**
     * {@inheritDoc}
     */
    protected void processGrammar( GrammarInfo grammarInfo )
        throws MojoExecutionException, MojoFailureException
    {
        File jtbFile = grammarInfo.getGrammarFile();
        File jtbDirectory = jtbFile.getParentFile();

        File tempDirectory = getTempDirectory();

        // setup output directory of grammar file (*.jj) generated by JTB
        File jjDirectory = tempDirectory;

        // setup output directory of tree node files (*.java) generated by JTB
        String nodePackage = grammarInfo.resolvePackageName( getNodePackageName() );
        File nodeDirectory = new File( tempDirectory, "node" );

        // setup output directory of visitor files (*.java) generated by JTB
        String visitorPackage = grammarInfo.resolvePackageName( getVisitorPackageName() );
        File visitorDirectory = new File( tempDirectory, "visitor" );

        // setup output directory of parser file (*.java) generated by JavaCC
        File parserDirectory = new File( tempDirectory, "parser" );

        // generate final grammar file and the node/visitor files
        JTB jtb = newJTB();
        jtb.setInputFile( jtbFile );
        jtb.setOutputDirectory( jjDirectory );
        jtb.setNodeDirectory( nodeDirectory );
        jtb.setVisitorDirectory( visitorDirectory );
        jtb.setNodePackageName( nodePackage );
        jtb.setVisitorPackageName( visitorPackage );
        jtb.run();

        // generate parser files
        JavaCC javacc = newJavaCC();
        javacc.setInputFile( jtb.getOutputFile() );
        javacc.setOutputDirectory( parserDirectory );
        javacc.run();

        // copy tree node files from JTB
        copyGrammarOutput( getInterimDirectory(), nodePackage, nodeDirectory, "!Node*" );

        // copy visitor files from JTB
        copyGrammarOutput( getInterimDirectory(), visitorPackage, visitorDirectory, "" );

        // copy parser files from JavaCC
        copyGrammarOutput( getOutputDirectory(), grammarInfo.getParserPackage(), parserDirectory,
                           grammarInfo.getParserName() + "*" );

        // copy source files which are next to grammar unless the grammar resides in an ordinary source root
        // (legacy support for custom sources)
        if ( !isSourceRoot( grammarInfo.getSourceDirectory() ) )
        {
            copyGrammarOutput( getOutputDirectory(), grammarInfo.getParserPackage(), jtbDirectory, "*" );
        }

        deleteTempDirectory( tempDirectory );
    }

    /**
     * Gets the effective package name for the AST node files.
     * 
     * @return The effective package name for the AST node files, never <code>null</code>.
     */
    private String getNodePackageName()
    {
        if ( this.packageName != null )
        {
            return this.packageName + ".syntaxtree";
        }
        else if ( this.nodePackageName != null )
        {
            return this.nodePackageName;
        }
        else
        {
            return "*.syntaxtree";
        }
    }

    /**
     * Gets the effective package name for the visitor files.
     * 
     * @return The effective package name for the visitor files, never <code>null</code>.
     */
    private String getVisitorPackageName()
    {
        if ( this.packageName != null )
        {
            return this.packageName + ".visitor";
        }
        else if ( this.visitorPackageName != null )
        {
            return this.visitorPackageName;
        }
        else
        {
            return "*.visitor";
        }
    }

    /**
     * Creates a new facade to invoke JTB. Most options for the invocation are derived from the current values of the
     * corresponding mojo parameters. The caller is responsible to set the input file, output directories and packages
     * on the returned facade.
     * 
     * @return The facade for the tool invocation, never <code>null</code>.
     */
    private JTB newJTB()
    {
        JTB jtb = new JTB();
        jtb.setLog( getLog() );
        jtb.setDescriptiveFieldNames( this.descriptiveFieldNames );
        jtb.setJavadocFriendlyComments( this.javadocFriendlyComments );
        jtb.setNodeParentClass( this.nodeParentClass );
        jtb.setParentPointers( this.parentPointers );
        jtb.setPrinter( this.printer );
        jtb.setScheme( this.scheme );
        jtb.setSpecialTokens( this.specialTokens );
        jtb.setSupressErrorChecking( this.supressErrorChecking );
        return jtb;
    }

}