de.u808.common.MD5Util.java Source code

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Here is the source code for de.u808.common.MD5Util.java

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/*
 * Copyright 2008-2009 Andreas Friedel
 *
 * 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 de.u808.common;

import java.math.BigInteger;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

/**
 * Utility class to create MD5 hashes.
 * @author Andreas Friedel
 *
 */
public class MD5Util {

    private MessageDigest md = null;

    private static MD5Util INSTANCE = null;

    private static Log log = LogFactory.getLog(MD5Util.class);

    private MD5Util() {
        try {
            md = MessageDigest.getInstance("MD5");
        } catch (NoSuchAlgorithmException e) {
            log.error("Failed to create MD5Util", e);
        }
    }

    /**
     * Singleton instantiate method.
     * 
     * @return The singleton instance of the class.
     */
    public static MD5Util getInstance() {
        if (INSTANCE == null) {
            INSTANCE = new MD5Util();
        }
        return INSTANCE;
    }

    /**
     * Creates MD5 Hex String for the input.  
     * 
     * @param s The string to create the hash for.
     * @return The MD5 Hex String for the input string.
     */
    public String getMD5Hex(String s) {
        md.update(s.getBytes(), 0, s.length());
        String md5Hex = new BigInteger(1, md.digest()).toString(16);
        md.reset();
        return md5Hex;
    }

}