Ant example source code file (Javah.java)

This example Ant source code file (Javah.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

arraylist, buildexception, buildexception, classargument, classargument, file, implementationspecificargument, io, path, path, string, string, stringbuffer, stringtokenizer, util, vector

The Javah.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;

import java.io.File;
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.StringTokenizer;
import java.util.Vector;
import org.apache.tools.ant.BuildException;
import org.apache.tools.ant.Project;
import org.apache.tools.ant.Task;
import org.apache.tools.ant.taskdefs.optional.javah.JavahAdapter;
import org.apache.tools.ant.taskdefs.optional.javah.JavahAdapterFactory;
import org.apache.tools.ant.types.Commandline;
import org.apache.tools.ant.types.Path;
import org.apache.tools.ant.types.Reference;
import org.apache.tools.ant.util.facade.FacadeTaskHelper;
import org.apache.tools.ant.util.facade.ImplementationSpecificArgument;

/**
 * Generates JNI header files using javah.
 *
 * This task can take the following arguments:
 * <ul>
 * <li>classname - the fully-qualified name of a class
 * <li>outputFile - Concatenates the resulting header or source files for all
 *     the classes listed into this file</li>
 * <li>destdir - Sets the directory where javah saves the header files or the
 *     stub files</li>
 * <li>classpath
 * <li>bootclasspath
 * <li>force - Specifies that output files should always be written
       (JDK1.2 only)</li>
 * <li>old - Specifies that old JDK1.0-style header files should be generated
 *     (otherwise output file contain JNI-style native method
 *      function prototypes) (JDK1.2 only)</li>
 * <li>stubs - generate C declarations from the Java object file (used with old)
 * <li>verbose - causes javah to print a message to stdout concerning the status
 *     of the generated files</li>
 * <li>extdirs - Override location of installed extensions
 * </ul>
 * Of these arguments, either <b>outputFile or destdir is required,
 * but not both. More than one classname may be specified, using a comma-separated
 * list or by using <code><class name="xxx"> elements within the task.
 * <p>
 * When this task executes, it will generate C header and source files that
 * are needed to implement native methods.
 *
 */

public class Javah extends Task {

    private Vector classes = new Vector(2);
    private String cls;
    private File destDir;
    private Path classpath = null;
    private File outputFile = null;
    private boolean verbose = false;
    private boolean force   = false;
    private boolean old     = false;
    private boolean stubs   = false;
    private Path bootclasspath;
    //private Path extdirs;
    private static String lSep = System.getProperty("line.separator");
    private FacadeTaskHelper facade = null;

    /**
     * No arg constructor.
     */
    public Javah() {
        facade = new FacadeTaskHelper(JavahAdapterFactory.getDefault());
    }

    /**
     * the fully-qualified name of the class (or classes, separated by commas).
     * @param cls the classname (or classnames).
     */
    public void setClass(String cls) {
        this.cls = cls;
    }

    /**
     * Adds class to process.
     * @return a <code>ClassArgument to be configured.
     */
    public ClassArgument createClass() {
        ClassArgument ga = new ClassArgument();
        classes.addElement(ga);
        return ga;
    }

    /**
     * A class corresponding the the nested "class" element.
     * It contains a "name" attribute.
     */
    public class ClassArgument {
        private String name;

        /** Constructor for ClassArgument. */
        public ClassArgument() {
        }

        /**
         * Set the name attribute.
         * @param name the name attribute.
         */
        public void setName(String name) {
            this.name = name;
        }

        /**
         * Get the name attribute.
         * @return the name attribute.
         */
        public String getName() {
            return name;
        }
    }

    /**
     * Names of the classes to process.
     * @return the array of classes.
     * @since Ant 1.6.3
     */
    public String[] getClasses() {
        ArrayList al = new ArrayList();
        if (cls != null) {
            StringTokenizer tok = new StringTokenizer(cls, ",", false);
            while (tok.hasMoreTokens()) {
                al.add(tok.nextToken().trim());
            }
        }

        Enumeration e = classes.elements();
        while (e.hasMoreElements()) {
            ClassArgument arg = (ClassArgument) e.nextElement();
            al.add(arg.getName());
        }
        return (String[]) al.toArray(new String[al.size()]);
    }

    /**
     * Set the destination directory into which the Java source
     * files should be compiled.
     * @param destDir the destination directory.
     */
    public void setDestdir(File destDir) {
        this.destDir = destDir;
    }

    /**
     * The destination directory, if any.
     * @return the destination directory.
     * @since Ant 1.6.3
     */
    public File getDestdir() {
        return destDir;
    }

    /**
     * the classpath to use.
     * @param src the classpath.
     */
    public void setClasspath(Path src) {
        if (classpath == null) {
            classpath = src;
        } else {
            classpath.append(src);
        }
    }

    /**
     * Path to use for classpath.
     * @return a path to be configured.
     */
    public Path createClasspath() {
        if (classpath == null) {
            classpath = new Path(getProject());
        }
        return classpath.createPath();
    }

    /**
     * Adds a reference to a classpath defined elsewhere.
     * @param r a reference to a classpath.
     * @todo this needs to be documented in the HTML docs.
     */
    public void setClasspathRef(Reference r) {
        createClasspath().setRefid(r);
    }

    /**
     * The classpath to use.
     * @return the classpath.
     * @since Ant 1.6.3
     */
    public Path getClasspath() {
        return classpath;
    }

    /**
     * location of bootstrap class files.
     * @param src the bootstrap classpath.
     */
    public void setBootclasspath(Path src) {
        if (bootclasspath == null) {
            bootclasspath = src;
        } else {
            bootclasspath.append(src);
        }
    }

    /**
     * Adds path to bootstrap class files.
     * @return a path to be configured.
     */
    public Path createBootclasspath() {
        if (bootclasspath == null) {
            bootclasspath = new Path(getProject());
        }
        return bootclasspath.createPath();
    }

    /**
     * To the bootstrap path, this adds a reference to a classpath defined elsewhere.
     * @param r a reference to a classpath
     * @todo this needs to be documented in the HTML.
     */
    public void setBootClasspathRef(Reference r) {
        createBootclasspath().setRefid(r);
    }

    /**
     * The bootclasspath to use.
     * @return the bootclass path.
     * @since Ant 1.6.3
     */
    public Path getBootclasspath() {
        return bootclasspath;
    }

    /**
     * Concatenates the resulting header or source files for all
     * the classes listed into this file.
     * @param outputFile the output file.
     */
    public void setOutputFile(File outputFile) {
        this.outputFile = outputFile;
    }

    /**
     * The destination file, if any.
     * @return the destination file.
     * @since Ant 1.6.3
     */
    public File getOutputfile() {
        return outputFile;
    }

    /**
     * If true, output files should always be written (JDK1.2 only).
     * @param force the value to use.
     */
    public void setForce(boolean force) {
        this.force = force;
    }

    /**
     * Whether output files should always be written.
     * @return the force attribute.
     * @since Ant 1.6.3
     */
    public boolean getForce() {
        return force;
    }

    /**
     * If true, specifies that old JDK1.0-style header files should be
     * generated.
     * (otherwise output file contain JNI-style native method function
     *  prototypes) (JDK1.2 only).
     * @param old if true use old 1.0 style header files.
     */
    public void setOld(boolean old) {
        this.old = old;
    }

    /**
     * Whether old JDK1.0-style header files should be generated.
     * @return the old attribute.
     * @since Ant 1.6.3
     */
    public boolean getOld() {
        return old;
    }

    /**
     * If true, generate C declarations from the Java object file (used with old).
     * @param stubs if true, generated C declarations.
     */
    public void setStubs(boolean stubs) {
        this.stubs = stubs;
    }

    /**
     * Whether C declarations from the Java object file should be generated.
     * @return the stubs attribute.
     * @since Ant 1.6.3
     */
    public boolean getStubs() {
        return stubs;
    }

    /**
     * If true, causes Javah to print a message concerning
     * the status of the generated files.
     * @param verbose if true, do verbose printing.
     */
    public void setVerbose(boolean verbose) {
        this.verbose = verbose;
    }

    /**
     * Whether verbose output should get generated.
     * @return the verbose attribute.
     * @since Ant 1.6.3
     */
    public boolean getVerbose() {
        return verbose;
    }

    /**
     * Choose the implementation for this particular task.
     * @param impl the name of the implemenation.
     * @since Ant 1.6.3
     */
    public void setImplementation(String impl) {
        if ("default".equals(impl)) {
            facade.setImplementation(JavahAdapterFactory.getDefault());
        } else {
            facade.setImplementation(impl);
        }
    }

    /**
     * Adds an implementation specific command-line argument.
     * @return a ImplementationSpecificArgument to be configured.
     *
     * @since Ant 1.6.3
     */
    public ImplementationSpecificArgument createArg() {
        ImplementationSpecificArgument arg =
            new ImplementationSpecificArgument();
        facade.addImplementationArgument(arg);
        return arg;
    }

    /**
     * Returns the (implementation specific) settings given as nested
     * arg elements.
     * @return the arguments.
     * @since Ant 1.6.3
     */
    public String[] getCurrentArgs() {
        return facade.getArgs();
    }

    /**
     * Execute the task
     *
     * @throws BuildException is there is a problem in the task execution.
     */
    public void execute() throws BuildException {
        // first off, make sure that we've got a srcdir

        if ((cls == null) && (classes.size() == 0)) {
            throw new BuildException("class attribute must be set!",
                getLocation());
        }

        if ((cls != null) && (classes.size() > 0)) {
            throw new BuildException("set class attribute or class element, "
                + "not both.", getLocation());
        }

        if (destDir != null) {
            if (!destDir.isDirectory()) {
                throw new BuildException("destination directory \"" + destDir
                    + "\" does not exist or is not a directory", getLocation());
            }
            if (outputFile != null) {
                throw new BuildException("destdir and outputFile are mutually "
                    + "exclusive", getLocation());
            }
        }

        if (classpath == null) {
            classpath = (new Path(getProject())).concatSystemClasspath("last");
        } else {
            classpath = classpath.concatSystemClasspath("ignore");
        }

        JavahAdapter ad =
            JavahAdapterFactory.getAdapter(facade.getImplementation(),
                                           this);
        if (!ad.compile(this)) {
            throw new BuildException("compilation failed");
        }
    }

    /**
     * Logs the compilation parameters, adds the files to compile and logs the
     * "niceSourceList"
     * @param cmd the command line.
     */
    public void logAndAddFiles(Commandline cmd) {
        logAndAddFilesToCompile(cmd);
    }

    /**
     * Logs the compilation parameters, adds the files to compile and logs the
     * "niceSourceList"
     * @param cmd the command line to add parameters to.
     */
    protected void logAndAddFilesToCompile(Commandline cmd) {
        log("Compilation " + cmd.describeArguments(),
            Project.MSG_VERBOSE);

        StringBuffer niceClassList = new StringBuffer();
        String[] c = getClasses();
        for (int i = 0; i < c.length; i++) {
            cmd.createArgument().setValue(c[i]);
            niceClassList.append("    ");
            niceClassList.append(c[i]);
            niceClassList.append(lSep);
        }

        StringBuffer prefix = new StringBuffer("Class");
        if (c.length > 1) {
            prefix.append("es");
        }
        prefix.append(" to be compiled:");
        prefix.append(lSep);

        log(prefix.toString() + niceClassList.toString(), Project.MSG_VERBOSE);
    }
}