/*
 * =============================================================================
 * 
 *   Copyright (c) 2007-2010, The JASYPT team (http://www.jasypt.org)
 * 
 *   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.jasypt.salt;

import java.io.UnsupportedEncodingException;

import org.jasypt.commons.CommonUtils;
import org.jasypt.exceptions.EncryptionInitializationException;

 This implementation of SaltGenerator always returns a fixed salt set by the user as a String, which is returned as salt bytes using the specified charset for conversion (UTF-8 by default). 

If the requested salt has a size in bytes smaller than the specified salt, 
the first n bytes are returned. If it is larger, an exception is thrown.


This class is thread-safe.

Author:
Daniel Fernández
Since:
1.2
Deprecated:
Deprecated in 1.9.2 in favour of StringFixedSaltGenerator, which implements the new FixedSaltGenerator interface and therefore is able to benefit from the performance improvements associated with it. This class will be removed in 1.10.0 (or 2.0.0)./**
 * <p>
 * This implementation of {@link SaltGenerator} always returns a fixed salt
 * set by the user as a String, which is returned as salt bytes using the 
 * specified charset for conversion (UTF-8 by default).
 * </p>
 * <p>
 * If the requested salt has a size in bytes smaller than the specified salt, 
 * the first n bytes are returned. If it is larger, an exception is thrown.
 * </p>
 * <p>
 * This class is <i>thread-safe</i>.
 * </p>
 * 
 * @since 1.2
 * 
 * @author Daniel Fern&aacute;ndez
 * 
 * @deprecated Deprecated in 1.9.2 in favour of {@link StringFixedSaltGenerator}, which
 *             implements the new {@link FixedSaltGenerator} interface and therefore is able to benefit
 *             from the performance improvements associated with it. This class will be removed
 *             in 1.10.0 (or 2.0.0).
 * 
 */
public class FixedStringSaltGenerator implements SaltGenerator {

    private static final String DEFAULT_CHARSET = "UTF-8";
    
    private String salt = null;
    private String charset = DEFAULT_CHARSET;
    
    private byte[] saltBytes = null;
    
    
Creates a new instance of FixedStringSaltGenerator
/**
     * Creates a new instance of <tt>FixedStringSaltGenerator</tt>
     *
     */
    public FixedStringSaltGenerator() {
        super();
    }

    
    
Sets the salt to be returned.
Params:
salt – the specified salt./**
     * Sets the salt to be returned.
     * 
     * @param salt the specified salt.
     */
    public synchronized void setSalt(final String salt) {
        CommonUtils.validateNotNull(salt, "Salt cannot be set null");
        this.salt = salt;
    }

    
    
Sets the charset to be applied to the salt for conversion into bytes.
Params:
charset – the specified charset/**
     * Sets the charset to be applied to the salt for conversion into bytes.
     * 
     * @param charset the specified charset
     */
    public synchronized void setCharset(final String charset) {
        CommonUtils.validateNotNull(charset, "Charset cannot be set null");
        this.charset = charset;
    }

    
    
Return salt with the specified byte length.
Params:
lengthBytes – length in bytes.
Returns:
the generated salt./**
     * Return salt with the specified byte length.
     * 
     * @param lengthBytes length in bytes.
     * @return the generated salt. 
     */
    public byte[] generateSalt(final int lengthBytes) {
        if (this.salt == null) {
            throw new EncryptionInitializationException(
                    "Salt has not been set");
        }
        if (this.saltBytes == null) {
            try {
                this.saltBytes = this.salt.getBytes(this.charset);
            } catch (UnsupportedEncodingException e) {
                throw new EncryptionInitializationException(
                    "Invalid charset specified: " + this.charset);
            }
        }
        if (this.saltBytes.length < lengthBytes) {
            throw new EncryptionInitializationException(
                    "Requested salt larger than set");
        }
        final byte[] generatedSalt = new byte[lengthBytes];
        System.arraycopy(this.saltBytes, 0, generatedSalt, 0, lengthBytes);
        return generatedSalt;
    }


    
As this salt generator provides a fixed salt, its inclusion 
unencrypted in encryption results
is not necessary, and in fact not desirable (so that it remains hidden).
Returns:
false/**
     * As this salt generator provides a fixed salt, its inclusion 
     * unencrypted in encryption results
     * is not necessary, and in fact not desirable (so that it remains hidden).
     * 
     * @return false
     */
    public boolean includePlainSaltInEncryptionResults() {
        return false;
    }

    
}