Ant example source code file (GUnzip.java)

This example Ant source code file (GUnzip.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, default_extension, default_extension, expanding, fileoutputstream, fileoutputstream, gunzip, gzipinputstream, gzipinputstream, inputstream, io, ioexception, problem, string, string, zip

The GUnzip.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.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.zip.GZIPInputStream;
import org.apache.tools.ant.BuildException;
import org.apache.tools.ant.util.FileUtils;

/**
 * Expands a file that has been compressed with the GZIP
 * algorithm. Normally used to compress non-compressed archives such
 * as TAR files.
 *
 * @since Ant 1.1
 *
 * @ant.task category="packaging"
 */

public class GUnzip extends Unpack {

    private static final String DEFAULT_EXTENSION = ".gz";

    /**
     * Get the default extension.
     * @return the value ".gz"
     */
    protected String getDefaultExtension() {
        return DEFAULT_EXTENSION;
    }

    /**
     * Implement the gunzipping.
     */
    protected void extract() {
        if (source.lastModified() > dest.lastModified()) {
            log("Expanding " + source.getAbsolutePath() + " to "
                        + dest.getAbsolutePath());

            FileOutputStream out = null;
            GZIPInputStream zIn = null;
            InputStream fis = null;
            try {
                out = new FileOutputStream(dest);
                fis = srcResource.getInputStream();
                zIn = new GZIPInputStream(fis);
                byte[] buffer = new byte[8 * 1024];
                int count = 0;
                do {
                    out.write(buffer, 0, count);
                    count = zIn.read(buffer, 0, buffer.length);
                } while (count != -1);
            } catch (IOException ioe) {
                String msg = "Problem expanding gzip " + ioe.getMessage();
                throw new BuildException(msg, ioe, getLocation());
            } finally {
                FileUtils.close(fis);
                FileUtils.close(out);
                FileUtils.close(zIn);
            }
        }
    }

    /**
     * Whether this task can deal with non-file resources.
     *
     * <p>This implementation returns true only if this task is
     * <gunzip>.  Any subclass of this class that also wants to
     * support non-file resources needs to override this method.  We
     * need to do so for backwards compatibility reasons since we
     * can't expect subclasses to support resources.</p>
     * @return true if this task supports non file resources.
     * @since Ant 1.7
     */
    protected boolean supportsNonFileResources() {
        return getClass().equals(GUnzip.class);
    }
}