MD5Generator.java

/**
 *       Copyright 2010 Newcastle University
 *
 *          http://research.ncl.ac.uk/smart/
 *
 * 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.amber.oauth2.as.issuer;

import java.security.MessageDigest;
import java.util.UUID;

import org.apache.amber.oauth2.common.exception.OAuthSystemException;


/**
 * Exemplar OAuth Token Generator
 *
 * @author Maciej Machulak (m.p.machulak@ncl.ac.uk)
 * @author Lukasz Moren (lukasz.moren@ncl.ac.uk)
 * @author Aad van Moorsel (aad.vanmoorsel@ncl.ac.uk)
 */
public class MD5Generator implements ValueGenerator {

    @Override
    public String generateValue() throws OAuthSystemException {
        return generateValue(UUID.randomUUID().toString());
    }

    @Override
    public String generateValue(String param) throws OAuthSystemException {
        try {
            MessageDigest algorithm = MessageDigest.getInstance("MD5");
            algorithm.reset();
            algorithm.update(param.getBytes());
            byte[] messageDigest = algorithm.digest();
            StringBuffer hexString = new StringBuffer();
            for (int i = 0; i < messageDigest.length; i++) {
                hexString.append(Integer.toHexString(0xFF & messageDigest[i]));
            }

            return hexString.toString();
        } catch (Exception e) {
            throw new OAuthSystemException("OAuth Token cannot be generated.", e);
        }
    }
}