Ant example source code file (JarLibDisplayTask.java)

This example Ant source code file (JarLibDisplayTask.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, directoryscanner, file, file, fileset, fileset, io, iterator, jarlibdisplaytask, librarydisplayer, string, string, task, util, vector

The JarLibDisplayTask.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.extension;

import java.io.File;
import java.util.Iterator;
import java.util.Vector;
import org.apache.tools.ant.BuildException;
import org.apache.tools.ant.DirectoryScanner;
import org.apache.tools.ant.Task;
import org.apache.tools.ant.types.FileSet;

/**
 * Displays the "Optional Package" and "Package Specification" information
 * contained within the specified JARs.
 *
 * <p>Prior to JDK1.3, an "Optional Package" was known as an Extension.
 * The specification for this mechanism is available in the JDK1.3
 * documentation in the directory
 * $JDK_HOME/docs/guide/extensions/versioning.html. Alternatively it is
 * available online at <a href="http://java.sun.com/j2se/1.3/docs/guide/extensions/versioning.html">
 * http://java.sun.com/j2se/1.3/docs/guide/extensions/versioning.html</a>.

 *
 * @ant.task name="jarlib-display"
 */
public class JarLibDisplayTask extends Task {
    /**
     * The library to display information about.
     */
    private File libraryFile;

    /**
     * Filesets specifying all the librarys
     * to display information about.
     */
    private final Vector libraryFileSets = new Vector();

    /**
     * The JAR library to display information for.
     *
     * @param file The jar library to display information for.
     */
    public void setFile(final File file) {
        this.libraryFile = file;
    }

    /**
     * Adds a set of files about which library data will be displayed.
     *
     * @param fileSet a set of files about which library data will be displayed.
     */
    public void addFileset(final FileSet fileSet) {
        libraryFileSets.addElement(fileSet);
    }

    /**
     * Execute the task.
     *
     * @throws BuildException if the task fails.
     */
    public void execute() throws BuildException {
        validate();

        final LibraryDisplayer displayer = new LibraryDisplayer();
        // Check if list of files to check has been specified
        if (!libraryFileSets.isEmpty()) {
            final Iterator iterator = libraryFileSets.iterator();
            while (iterator.hasNext()) {
                final FileSet fileSet = (FileSet) iterator.next();
                final DirectoryScanner scanner
                    = fileSet.getDirectoryScanner(getProject());
                final File basedir = scanner.getBasedir();
                final String[] files = scanner.getIncludedFiles();
                for (int i = 0; i < files.length; i++) {
                    final File file = new File(basedir, files[ i ]);
                    displayer.displayLibrary(file);
                }
            }
        } else {
            displayer.displayLibrary(libraryFile);
        }
    }

    /**
     * Validate the tasks parameters.
     *
     * @throws BuildException if invalid parameters found
     */
    private void validate() throws BuildException {
        if (null == libraryFile && libraryFileSets.isEmpty()) {
            final String message = "File attribute not specified.";
            throw new BuildException(message);
        }
        if (null != libraryFile && !libraryFile.exists()) {
            final String message = "File '" + libraryFile + "' does not exist.";
            throw new BuildException(message);
        }
        if (null != libraryFile && !libraryFile.isFile()) {
            final String message = "\'" + libraryFile + "\' is not a file.";
            throw new BuildException(message);
        }
    }
}