| career | drupal | java | mac | mysql | perl | scala | uml | unix  

Ant example source code file (

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

Java - Ant tags/keywords

algorithm, algorithm, exception, exception, hashvaluealgorithm, hashvaluealgorithm, io, string, string

The 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
 *  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.



 * Computes a 'hashvalue' for the content of file using String.hashValue().
 * Use of this algorithm doesn't require any additional nested <param>s and
 * doesn't support any.
 * @version 2003-09-13
 * @since  Ant 1.6
public class HashvalueAlgorithm implements Algorithm {

     * This algorithm doesn't need any configuration.
     * Therefore it's always valid.
     * @return always true
    public boolean isValid() {
        return true;

     * Computes a 'hashvalue' for a file content.
     * It reads the content of a file, convert that to String and use the
     * String.hashCode() method.
     * @param file  The file for which the value should be computed
     * @return the hashvalue or <i>null if the file couldn't be read
     // Because the content is only read the file will not be damaged. I tested
     // with JPG, ZIP and PDF as binary files.
    public String getValue(File file) {
        try {
            if (!file.canRead()) {
                return null;
   fis = new;
            byte[] content = new byte[fis.available()];
            String s = new String(content);
            int hash = s.hashCode();
            return Integer.toString(hash);
        } catch (Exception e) {
            return null;

     * Override Object.toString().
     * @return information about this comparator
    public String toString() {
        return "HashvalueAlgorithm";


Other Ant examples (source code examples)

Here is a short list of links related to this Ant source code file:

... this post is sponsored by my books ...

#1 New Release!

FP Best Seller


new blog posts


Copyright 1998-2021 Alvin Alexander,
All Rights Reserved.

A percentage of advertising revenue from
pages under the /java/jwarehouse URI on this website is
paid back to open source projects.