org.soulwing.crypt4j.DesCrypt.java Source code

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Here is the source code for org.soulwing.crypt4j.DesCrypt.java

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/*
 * File created on Feb 28, 2014 
 *
 * Copyright (c) 2014 Carl Harris, Jr.
 *
 * 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 org.soulwing.crypt4j;

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

import org.apache.commons.codec.digest.UnixCrypt;

/**
 * A DES crypt implementation that simply delegates to the implementation
 * in Commons Codec.
 *
 * @author Carl Harris
 */
class DesCrypt extends Crypt {

    private static final String UNIX_CRYPT_CLASS = "org.apache.commons.codec.digest.UnixCrypt";

    /**
     * Constructs a new instance.
     * @param type
     */
    public DesCrypt(Type type) {
        super(type);
    }

    /**
     * {@inheritDoc}
     */
    @Override
    protected String doCrypt(Password password, Salt salt)
            throws NoSuchAlgorithmException, UnsupportedEncodingException {
        checkUnixCryptAvailability();
        return UnixCrypt.crypt(password.getBytes(CHARACTER_ENCODING), salt.getText(2));
    }

    private void checkUnixCryptAvailability() throws NoSuchAlgorithmException {
        try {
            getClassLoader().loadClass(UNIX_CRYPT_CLASS);
        } catch (ClassNotFoundException ex) {
            throw new NoSuchAlgorithmException("DES unavailable; Commons Codec library not on classpath");
        }
    }

    private ClassLoader getClassLoader() {
        ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
        if (classLoader == null) {
            classLoader = getClass().getClassLoader();
        }
        return classLoader;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    protected String encodePassword(byte[] password) {
        throw new UnsupportedOperationException();
    }

}