Ant example source code file (ManifestTask.java)

This example Ant source code file (ManifestTask.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, failed, fileinputstream, fileoutputstream, inputstreamreader, io, manifest, manifest, manifestexception, manifestexception, manifesttask, mode, string, string, util

The ManifestTask.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;

import java.io.File;
import java.io.FileInputStream;
import java.io.InputStreamReader;
import java.io.FileOutputStream;
import java.io.OutputStreamWriter;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Enumeration;

import org.apache.tools.ant.BuildException;
import org.apache.tools.ant.Project;
import org.apache.tools.ant.Task;
import org.apache.tools.ant.util.FileUtils;
import org.apache.tools.ant.types.EnumeratedAttribute;

/**
 * Creates a manifest file for inclusion in a JAR, Ant task wrapper
 * around {@link Manifest Manifest}.  This task can be used to write a
 * Manifest file, optionally replacing or updating an existing file.
 *
 * @since Ant 1.5
 *
 * @ant.task category="java"
 */
public class ManifestTask extends Task {

    /**
     * Holds the real data.
     */
    private Manifest nestedManifest = new Manifest();

    /**
     * The file to which the manifest should be written when used as a task
     */
    private File manifestFile;

    /**
     * The mode with which the manifest file is written
     */
    private Mode mode;

    /**
     * The encoding of the manifest file
     */
    private String encoding;

    /**
     * Helper class for Manifest's mode attribute.
     */
    public static class Mode extends EnumeratedAttribute {
        /**
         * Get Allowed values for the mode attribute.
         *
         * @return a String array of the allowed values.
         */
        public String[] getValues() {
            return new String[] {"update", "replace"};
        }
    }

    /**
     * Default constructor
     */
    public ManifestTask() {
        mode = new Mode();
        mode.setValue("replace");
    }

    /**
     * Add a section to the manifest
     *
     * @param section the manifest section to be added
     *
     * @exception ManifestException if the section is not valid.
     */
    public void addConfiguredSection(Manifest.Section section)
         throws ManifestException {
        nestedManifest.addConfiguredSection(section);
    }

    /**
     * Add an attribute to the manifest - it is added to the main section.
     *
     * @param attribute the attribute to be added.
     *
     * @exception ManifestException if the attribute is not valid.
     */
    public void addConfiguredAttribute(Manifest.Attribute attribute)
         throws ManifestException {
        nestedManifest.addConfiguredAttribute(attribute);
    }

    /**
     * The name of the manifest file to create/update.
     * Required if used as a task.
     * @param f the Manifest file to be written
     */
    public void setFile(File f) {
        manifestFile = f;
    }

    /**
     * The encoding to use for reading in an existing manifest file
     * @param encoding the manifest file encoding.
     */
    public void setEncoding(String encoding) {
        this.encoding = encoding;
    }

    /**
     * Update policy: either "update" or "replace"; default is "replace".
     * @param m the mode value - update or replace.
     */
    public void setMode(Mode m) {
        mode = m;
    }

    /**
     * Create or update the Manifest when used as a task.
     *
     * @throws BuildException if the manifest cannot be written.
     */
    public void execute() throws BuildException {
        if (manifestFile == null) {
            throw new BuildException("the file attribute is required");
        }

        Manifest toWrite = Manifest.getDefaultManifest();
        Manifest current = null;
        BuildException error = null;

        if (manifestFile.exists()) {
            FileInputStream fis = null;
            InputStreamReader isr = null;
            try {
                fis = new FileInputStream(manifestFile);
                if (encoding == null) {
                    isr = new InputStreamReader(fis, "UTF-8");
                } else {
                    isr = new InputStreamReader(fis, encoding);
                }
                current = new Manifest(isr);
            } catch (ManifestException m) {
                error = new BuildException("Existing manifest " + manifestFile
                                           + " is invalid", m, getLocation());
            } catch (IOException e) {
                error = new BuildException("Failed to read " + manifestFile,
                                           e, getLocation());
            } finally {
                FileUtils.close(isr);
            }
        }

        //look for and print warnings
        for (Enumeration e = nestedManifest.getWarnings();
                e.hasMoreElements();) {
            log("Manifest warning: " + (String) e.nextElement(),
                    Project.MSG_WARN);
        }
        try {
            if (mode.getValue().equals("update") && manifestFile.exists()) {
                if (current != null) {
                    toWrite.merge(current);
                } else if (error != null) {
                    throw error;
                }
            }

            toWrite.merge(nestedManifest);
        } catch (ManifestException m) {
            throw new BuildException("Manifest is invalid", m, getLocation());
        }

        if (toWrite.equals(current)) {
            log("Manifest has not changed, do not recreate",
                Project.MSG_VERBOSE);
            return;
        }

        PrintWriter w = null;
        try {
            FileOutputStream fos = new FileOutputStream(manifestFile);
            OutputStreamWriter osw = new OutputStreamWriter(fos, Manifest.JAR_ENCODING);
            w = new PrintWriter(osw);
            toWrite.write(w);
        } catch (IOException e) {
            throw new BuildException("Failed to write " + manifestFile,
                                     e, getLocation());
        } finally {
            if (w != null) {
                w.close();
            }
        }
    }

}