- /*
- * Copyright 2003-2004 The Apache Software Foundation
- *
- * Licensed 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.types.selectors.modifiedselector;
-
-
- import java.io.File;
-
-
- /**
- * 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</i> 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;
- }
- java.io.FileInputStream fis = new java.io.FileInputStream(file);
- byte[] content = new byte[fis.available()];
- fis.read(content);
- fis.close();
- 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";
- }
-
- }