Ant example source code file (JJTree.java)

This example Ant source code file (JJTree.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Ant tags/keywords

buildexception, buildexception, default_suffix, default_suffix, file, file, hashtable, io, jjtree, node_default_void, node_package, output_file, static, string, string, util

The JJTree.java source code

/*
 *  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.tools.ant.taskdefs.optional.javacc;

import java.io.File;
import java.io.IOException;
import java.util.Enumeration;
import java.util.Hashtable;

import org.apache.tools.ant.BuildException;
import org.apache.tools.ant.Project;
import org.apache.tools.ant.Task;
import org.apache.tools.ant.taskdefs.Execute;
import org.apache.tools.ant.taskdefs.LogStreamHandler;
import org.apache.tools.ant.types.Commandline;
import org.apache.tools.ant.types.CommandlineJava;
import org.apache.tools.ant.types.Path;
import org.apache.tools.ant.util.JavaEnvUtils;

/**
 * Runs the JJTree compiler compiler.
 *
 */
public class JJTree extends Task {

    // keys to optional attributes
    private static final String OUTPUT_FILE       = "OUTPUT_FILE";
    private static final String BUILD_NODE_FILES  = "BUILD_NODE_FILES";
    private static final String MULTI             = "MULTI";
    private static final String NODE_DEFAULT_VOID = "NODE_DEFAULT_VOID";
    private static final String NODE_FACTORY      = "NODE_FACTORY";
    private static final String NODE_SCOPE_HOOK   = "NODE_SCOPE_HOOK";
    private static final String NODE_USES_PARSER  = "NODE_USES_PARSER";
    private static final String STATIC            = "STATIC";
    private static final String VISITOR           = "VISITOR";

    private static final String NODE_PACKAGE      = "NODE_PACKAGE";
    private static final String VISITOR_EXCEPTION = "VISITOR_EXCEPTION";
    private static final String NODE_PREFIX       = "NODE_PREFIX";

    private final Hashtable optionalAttrs = new Hashtable();

    private String outputFile = null;

    private static final String DEFAULT_SUFFIX = ".jj";

    // required attributes
    private File outputDirectory = null;
    private File targetFile      = null;
    private File javaccHome      = null;

    private CommandlineJava cmdl = new CommandlineJava();


    /**
     * Sets the BUILD_NODE_FILES grammar option.
     * @param buildNodeFiles a <code>boolean value.
     */
    public void setBuildnodefiles(boolean buildNodeFiles) {
        optionalAttrs.put(BUILD_NODE_FILES, buildNodeFiles ? Boolean.TRUE : Boolean.FALSE);
    }

    /**
     * Sets the MULTI grammar option.
     * @param multi a <code>boolean value.
     */
    public void setMulti(boolean multi) {
        optionalAttrs.put(MULTI, multi ? Boolean.TRUE : Boolean.FALSE);
    }

    /**
     * Sets the NODE_DEFAULT_VOID grammar option.
     * @param nodeDefaultVoid a <code>boolean value.
     */
    public void setNodedefaultvoid(boolean nodeDefaultVoid) {
        optionalAttrs.put(NODE_DEFAULT_VOID, nodeDefaultVoid ? Boolean.TRUE : Boolean.FALSE);
    }

    /**
     * Sets the NODE_FACTORY grammar option.
     * @param nodeFactory a <code>boolean value.
     */
    public void setNodefactory(boolean nodeFactory) {
        optionalAttrs.put(NODE_FACTORY, nodeFactory ? Boolean.TRUE : Boolean.FALSE);
    }

    /**
     * Sets the NODE_SCOPE_HOOK grammar option.
     * @param nodeScopeHook a <code>boolean value.
     */
    public void setNodescopehook(boolean nodeScopeHook) {
        optionalAttrs.put(NODE_SCOPE_HOOK, nodeScopeHook ? Boolean.TRUE : Boolean.FALSE);
    }

    /**
     * Sets the NODE_USES_PARSER grammar option.
     * @param nodeUsesParser a <code>boolean value.
     */
    public void setNodeusesparser(boolean nodeUsesParser) {
        optionalAttrs.put(NODE_USES_PARSER, nodeUsesParser ? Boolean.TRUE : Boolean.FALSE);
    }

    /**
     * Sets the STATIC grammar option.
     * @param staticParser a <code>boolean value.
     */
    public void setStatic(boolean staticParser) {
        optionalAttrs.put(STATIC, staticParser ? Boolean.TRUE : Boolean.FALSE);
    }

    /**
     * Sets the VISITOR grammar option.
     * @param visitor a <code>boolean value.
     */
    public void setVisitor(boolean visitor) {
        optionalAttrs.put(VISITOR, visitor ? Boolean.TRUE : Boolean.FALSE);
    }

    /**
     * Sets the NODE_PACKAGE grammar option.
     * @param nodePackage the option to use.
     */
    public void setNodepackage(String nodePackage) {
        optionalAttrs.put(NODE_PACKAGE, nodePackage);
    }

    /**
     * Sets the VISITOR_EXCEPTION grammar option.
     * @param visitorException the option to use.
     */
    public void setVisitorException(String visitorException) {
        optionalAttrs.put(VISITOR_EXCEPTION, visitorException);
    }

    /**
     * Sets the NODE_PREFIX grammar option.
     * @param nodePrefix the option to use.
     */
    public void setNodeprefix(String nodePrefix) {
        optionalAttrs.put(NODE_PREFIX, nodePrefix);
    }

    /**
     * The directory to write the generated JavaCC grammar and node files to.
     * If not set, the files are written to the directory
     * containing the grammar file.
     * @param outputDirectory the output directory.
     */
    public void setOutputdirectory(File outputDirectory) {
        this.outputDirectory = outputDirectory;
    }

    /**
     * The outputfile to write the generated JavaCC grammar file to.
     * If not set, the file is written with the same name as
     * the JJTree grammar file with a suffix .jj.
     * @param outputFile the output file name.
     */
    public void setOutputfile(String outputFile) {
        this.outputFile = outputFile;
    }

    /**
     * The jjtree grammar file to process.
     * @param targetFile the grammar file.
     */
    public void setTarget(File targetFile) {
        this.targetFile = targetFile;
    }

    /**
     * The directory containing the JavaCC distribution.
     * @param javaccHome the directory containing JavaCC.
     */
    public void setJavacchome(File javaccHome) {
        this.javaccHome = javaccHome;
    }

    /**
     * Constructor
     */
    public JJTree() {
        cmdl.setVm(JavaEnvUtils.getJreExecutable("java"));
    }

    /**
     * Run the task.
     * @throws BuildException on error.
     */
    public void execute() throws BuildException {

        // load command line with optional attributes
        Enumeration iter = optionalAttrs.keys();
        while (iter.hasMoreElements()) {
            String name  = (String) iter.nextElement();
            Object value = optionalAttrs.get(name);
            cmdl.createArgument().setValue("-" + name + ":" + value.toString());
        }

        if (targetFile == null || !targetFile.isFile()) {
            throw new BuildException("Invalid target: " + targetFile);
        }

        File javaFile = null;

        // use the directory containing the target as the output directory
        if (outputDirectory == null) {
            // convert backslashes to slashes, otherwise jjtree will
            // put this as comments and this seems to confuse javacc
            cmdl.createArgument().setValue("-OUTPUT_DIRECTORY:"
                                           + getDefaultOutputDirectory());

            javaFile = new File(createOutputFileName(targetFile, outputFile,
                                                     null));
        } else {
            if (!outputDirectory.isDirectory()) {
                throw new BuildException("'outputdirectory' " + outputDirectory
                                         + " is not a directory.");
            }

            // convert backslashes to slashes, otherwise jjtree will
            // put this as comments and this seems to confuse javacc
            cmdl.createArgument().setValue("-OUTPUT_DIRECTORY:"
                                           + outputDirectory.getAbsolutePath()
                                             .replace('\\', '/'));

            javaFile = new File(createOutputFileName(targetFile, outputFile,
                                                     outputDirectory
                                                     .getPath()));
        }

        if (javaFile.exists()
            && targetFile.lastModified() < javaFile.lastModified()) {
            log("Target is already built - skipping (" + targetFile + ")",
                Project.MSG_VERBOSE);
            return;
        }

        if (outputFile != null) {
            cmdl.createArgument().setValue("-" + OUTPUT_FILE + ":"
                                           + outputFile.replace('\\', '/'));
        }

        cmdl.createArgument().setValue(targetFile.getAbsolutePath());

        final Path classpath = cmdl.createClasspath(getProject());
        final File javaccJar = JavaCC.getArchiveFile(javaccHome);
        classpath.createPathElement().setPath(javaccJar.getAbsolutePath());
        classpath.addJavaRuntime();

        cmdl.setClassname(JavaCC.getMainClass(classpath,
                                              JavaCC.TASKDEF_TYPE_JJTREE));

        final Commandline.Argument arg = cmdl.createVmArgument();
        arg.setValue("-mx140M");
        arg.setValue("-Dinstall.root=" + javaccHome.getAbsolutePath());

        final Execute process =
            new Execute(new LogStreamHandler(this,
                                             Project.MSG_INFO,
                                             Project.MSG_INFO),
                        null);
        log(cmdl.describeCommand(), Project.MSG_VERBOSE);
        process.setCommandline(cmdl.getCommandline());

        try {
            if (process.execute() != 0) {
                throw new BuildException("JJTree failed.");
            }
        } catch (IOException e) {
            throw new BuildException("Failed to launch JJTree", e);
        }
    }

    private String createOutputFileName(File destFile, String optionalOutputFile,
                                        String outputDir) {
        optionalOutputFile = validateOutputFile(optionalOutputFile,
                                                outputDir);
        String jjtreeFile = destFile.getAbsolutePath().replace('\\', '/');

        if ((optionalOutputFile == null) || optionalOutputFile.equals("")) {
            int filePos = jjtreeFile.lastIndexOf("/");

            if (filePos >= 0) {
                jjtreeFile = jjtreeFile.substring(filePos + 1);
            }

            int suffixPos = jjtreeFile.lastIndexOf('.');

            if (suffixPos == -1) {
                optionalOutputFile = jjtreeFile + DEFAULT_SUFFIX;
            } else {
                String currentSuffix = jjtreeFile.substring(suffixPos);

                if (currentSuffix.equals(DEFAULT_SUFFIX)) {
                    optionalOutputFile = jjtreeFile + DEFAULT_SUFFIX;
                } else {
                    optionalOutputFile = jjtreeFile.substring(0, suffixPos)
                        + DEFAULT_SUFFIX;
                }
            }
        }

        if ((outputDir == null) || outputDir.equals("")) {
            outputDir = getDefaultOutputDirectory();
        }

        return (outputDir + "/" + optionalOutputFile).replace('\\', '/');
    }

    /**
     * When running JJTree from an Ant taskdesk the -OUTPUT_DIRECTORY must
     * always be set. But when -OUTPUT_DIRECTORY is set, -OUTPUT_FILE is
     * handled as if relative of this -OUTPUT_DIRECTORY. Thus when the
     * -OUTPUT_FILE is absolute or contains a drive letter we have a problem.
     *
     * @param destFile
     * @param outputDir
     * @return
     * @throws BuildException
     */
    private String validateOutputFile(String destFile,
                                      String outputDir)
        throws BuildException {
        if (destFile == null) {
            return null;
        }

        if ((outputDir == null)
            && (destFile.startsWith("/") || destFile.startsWith("\\"))) {
            String relativeOutputFile = makeOutputFileRelative(destFile);
            setOutputfile(relativeOutputFile);

            return relativeOutputFile;
        }

        String root = getRoot(new File(destFile)).getAbsolutePath();

        if ((root.length() > 1)
            && destFile.startsWith(root.substring(0, root.length() - 1))) {
            throw new BuildException("Drive letter in 'outputfile' not "
                                     + "supported: " + destFile);
        }

        return destFile;
    }

    private String makeOutputFileRelative(String destFile) {
        StringBuffer relativePath = new StringBuffer();
        String defaultOutputDirectory = getDefaultOutputDirectory();
        int nextPos = defaultOutputDirectory.indexOf('/');
        int startPos = nextPos + 1;

        while (startPos > -1 && startPos < defaultOutputDirectory.length()) {
            relativePath.append("/..");
            nextPos = defaultOutputDirectory.indexOf('/', startPos);

            if (nextPos == -1) {
                startPos = nextPos;
            } else {
                startPos = nextPos + 1;
            }
        }

        relativePath.append(destFile);

        return relativePath.toString();
    }

    private String getDefaultOutputDirectory() {
        return getProject().getBaseDir().getAbsolutePath().replace('\\', '/');
    }

    /**
     * Determine root directory for a given file.
     *
     * @param file
     * @return file's root directory
     */
    private File getRoot(File file) {
        File root = file.getAbsoluteFile();

        while (root.getParent() != null) {
            root = root.getParentFile();
        }

        return root;
    }
}