1/*
2 *  Licensed to the Apache Software Foundation (ASF) under one or more
3 *  contributor license agreements.  See the NOTICE file distributed with
4 *  this work for additional information regarding copyright ownership.
5 *  The ASF licenses this file to You under the Apache License, Version 2.0
6 *  (the "License"); you may not use this file except in compliance with
7 *  the License.  You may obtain a copy of the License at
8 *
9 *     http://www.apache.org/licenses/LICENSE-2.0
10 *
11 *  Unless required by applicable law or agreed to in writing, software
12 *  distributed under the License is distributed on an "AS IS" BASIS,
13 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 *  See the License for the specific language governing permissions and
15 *  limitations under the License.
16 */
17
18package javax.crypto;
19
20import java.security.InvalidKeyException;
21import java.security.spec.InvalidKeySpecException;
22import java.security.spec.KeySpec;
23
24/**
25 * The <i>Service Provider Interface</i> (<b>SPI</b>) definition for the {@code
26 * SecretKeyFactory} class.
27 */
28public abstract class SecretKeyFactorySpi {
29
30    /**
31     * Creates a new {@code SecretKeyFactorySpi} instance.
32     */
33    public SecretKeyFactorySpi() {
34    }
35
36    /**
37     * Generate a secret key from the specified key specification.
38     *
39     * @param keySpec
40     *            the key specification.
41     * @return a secret key.
42     * @throws InvalidKeySpecException
43     *             if the specified key specification cannot be used to generate
44     *             a secret key.
45     */
46    protected abstract SecretKey engineGenerateSecret(KeySpec keySpec)
47            throws InvalidKeySpecException;
48
49    /**
50     * Returns the key specification of the specified secret key.
51     *
52     * @param key
53     *            the secret key to get the specification from.
54     * @param keySpec
55     *            the target key specification class.
56     * @return an instance of the specified key specification class.
57     * @throws InvalidKeySpecException
58     *             if the specified secret key cannot be transformed into the
59     *             requested key specification.
60     */
61    @SuppressWarnings("unchecked")
62    protected abstract KeySpec engineGetKeySpec(SecretKey key, Class keySpec)
63            throws InvalidKeySpecException;
64
65    /**
66     * Translates the specified secret key into an instance of the corresponding
67     * key from the provider of this key factory.
68     *
69     * @param key
70     *            the secret key to translate.
71     * @return the corresponding translated key.
72     * @throws InvalidKeyException
73     *             if the specified key cannot be translated using this key
74     *             factory.
75     */
76    protected abstract SecretKey engineTranslateKey(SecretKey key)
77            throws InvalidKeyException;
78}