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* </tr> * <tr> * <td> algorithm.algorithm * <td> MD5 | SHA (default provider) * <td> name of the algorithm the provider should use * <td> no, defaults to MD5 * </tr> * <tr> * <td> algorithm.provider * <td> * <td> name of the provider to use * <td> no, defaults to null * </tr> * </table> * * @version 2004-07-08 * @since Ant 1.6 */ public class DigestAlgorithm implements Algorithm { // ----- member variables ----- /** * MessageDigest algorithm to be used. */ private String algorithm = "MD5"; /** * MessageDigest Algorithm provider */ private String provider = null; /** * Message Digest instance */ private MessageDigest messageDigest = null; /** * Size of the read buffer to use. */ private int readBufferSize = 8 * 1024; // ----- Algorithm-Configuration ----- /** * Specifies the algorithm to be used to compute the checksum. * Defaults to "MD5". Other popular algorithms like "SHA" may be used as well. * @param algorithm the digest algorithm to use */ public void setAlgorithm(String algorithm) { this.algorithm = algorithm; } /** * Sets the MessageDigest algorithm provider to be used * to calculate the checksum. * @param provider provider to use */ public void setProvider(String provider) { this.provider = provider; } /** Initialize the security message digest. */ public void initMessageDigest() { if (messageDigest != null) { return; } if ((provider != null) && !"".equals(provider) && !"null".equals(provider)) { try { messageDigest = MessageDigest.getInstance(algorithm, provider); } catch (NoSuchAlgorithmException noalgo) { throw new BuildException(noalgo); } catch (NoSuchProviderException noprovider) { throw new BuildException(noprovider); } } else { try { messageDigest = MessageDigest.getInstance(algorithm); } catch (NoSuchAlgorithmException noalgo) { throw new BuildException(noalgo); } } } // ----- Logic ----- /** * This algorithm supports only MD5 and SHA. * @return <i>true if all is ok, otherwise false. */ public boolean isValid() { return "SHA".equalsIgnoreCase(algorithm) || "MD5".equalsIgnoreCase(algorithm); } /** * Computes a value for a file content with the specified digest algorithm. * @param file File object for which the value should be evaluated. * @return The value for that file */ // implementation adapted from ...taskdefs.Checksum, thanks to Magesh for hint public String getValue(File file) { initMessageDigest(); String checksum = null; try { if (!file.canRead()) { return null; } FileInputStream fis = null; byte[] buf = new byte[readBufferSize]; try { messageDigest.reset(); fis = new FileInputStream(file); DigestInputStream dis = new DigestInputStream(fis, messageDigest); while (dis.read(buf, 0, readBufferSize) != -1) { // do nothing } dis.close(); fis.close(); fis = null; byte[] fileDigest = messageDigest.digest(); StringBuffer checksumSb = new StringBuffer(); for (int i = 0; i < fileDigest.length; i++) { String hexStr = Integer.toHexString(0x00ff & fileDigest[i]); if (hexStr.length() < 2) { checksumSb.append("0"); } checksumSb.append(hexStr); } checksum = checksumSb.toString(); } catch (Exception e) { return null; } } catch (Exception e) { return null; } return checksum; } /** * Override Object.toString(). * @return some information about this algorithm. */ public String toString() { StringBuffer buf = new StringBuffer(); buf.append("<DigestAlgorithm:"); buf.append("algorithm=").append(algorithm); buf.append(";provider=").append(provider); buf.append(">"); return buf.toString(); } }

Other Ant examples (source code examples)

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Ant example source code file (DigestAlgorithm.java)

This example Ant source code file (DigestAlgorithm.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, digestalgorithm, digestalgorithm, digestinputstream, exception, fileinputstream, io, md5, nosuchalgorithmexception, nosuchproviderexception, security, string, string, stringbuffer, stringbuffer

The DigestAlgorithm.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.types.selectors.modifiedselector;


import java.io.File;
import java.io.FileInputStream;
import java.security.DigestInputStream;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.security.NoSuchProviderException;
import org.apache.tools.ant.BuildException;


/**
 * Computes a 'hashvalue' for the content of file using
 * java.security.MessageDigest.
 * Use of this algorithm doesn't require any additional nested <param>s.
 * Supported <param>s are:
 * <table>
 * <tr>
 *   <th>name
valuesdescriptionrequired
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