org.taverna.server.master.worker.PasswordIssuer.java Source code

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Here is the source code for org.taverna.server.master.worker.PasswordIssuer.java

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package org.taverna.server.master.worker;
/*
 * 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.
 */

import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;

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

/**
 * A simple password issuing bean.
 * 
 * @author Donal Fellows
 */
public class PasswordIssuer {
    private static final char[] ALPHABET = { 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n',
            'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I',
            'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', '1', '2', '3', '4',
            '5', '6', '7', '8', '9', '0', '!', '@', '#', '$', '%', '^', '&', '*', '(', ')', ',', '.', '<', '>', '/',
            '?', ':', ';', '-', '_', '+', '[', ']', '{', '}', '`', '~' };
    private Log log = LogFactory.getLog("Taverna.Server.Worker");
    private SecureRandom r;
    private int length;

    public PasswordIssuer() {
        r = new SecureRandom();
        log.info("constructing passwords with " + r.getAlgorithm());
        setLength(8);
    }

    public PasswordIssuer(String algorithm) throws NoSuchAlgorithmException {
        r = SecureRandom.getInstance(algorithm);
        log.info("constructing passwords with " + r.getAlgorithm());
        setLength(8);
    }

    public void setLength(int length) {
        this.length = length;
        log.info("issued password will be " + this.length + " symbols chosen from " + ALPHABET.length);
    }

    /**
     * Issue a password.
     * 
     * @return The new password.
     */
    public String issue() {
        StringBuilder sb = new StringBuilder();
        for (int i = 0; i < length; i++)
            sb.append(ALPHABET[r.nextInt(ALPHABET.length)]);
        log.info("issued new password of length " + sb.length());
        return sb.toString();
    }
}