org.apache.wookie.util.HashGenerator.java Source code

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Here is the source code for org.apache.wookie.util.HashGenerator.java

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/*
 *  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.
 */

/**
 * from http://www.devbistro.com/articles/Java/Password-Encryption
 */
package org.apache.wookie.util;

import java.io.UnsupportedEncodingException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

import org.apache.commons.codec.binary.Base64;
import org.apache.wookie.exceptions.SystemUnavailableException;

/**
 * A class for generating digests/hashing
 * @author Paul Sharples
 * @version $Id: HashGenerator.java,v 1.2 2009-07-28 16:05:21 scottwilson Exp $
 */
public final class HashGenerator {

    private static HashGenerator _instance;

    private final String _defaultAlgorithm = "SHA";

    private String _algorithm = _defaultAlgorithm;

    private HashGenerator() {
    }

    public synchronized String encrypt(String pText, String algorithm) throws SystemUnavailableException {
        _algorithm = algorithm;
        return generateEncryption(pText);
    }

    public synchronized String encrypt(String pText) throws SystemUnavailableException {
        // always set this back to SHA in case it was chnaged
        _algorithm = _defaultAlgorithm;
        return generateEncryption(pText);
    }

    public synchronized String generateEncryption(String plaintext) throws SystemUnavailableException {

        MessageDigest md = null;
        try {
            md = MessageDigest.getInstance(_algorithm);
        } catch (NoSuchAlgorithmException e) {
            throw new SystemUnavailableException(e.getMessage());
        }
        try {
            md.update(plaintext.getBytes("UTF-8"));
        } catch (UnsupportedEncodingException e) {
            throw new SystemUnavailableException(e.getMessage());
        }

        byte raw[] = md.digest(); //step 4
        String hash = new String((new Base64()).encode(raw));
        return hash; //step 6
    }

    public static synchronized HashGenerator getInstance() {

        if (_instance == null) {
            _instance = new HashGenerator();
        }
        return _instance;
    }
}