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      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 
     18 package javax.crypto;
     19 
     20 import java.security.AlgorithmParameters;
     21 import java.security.InvalidAlgorithmParameterException;
     22 import java.security.InvalidKeyException;
     23 import java.security.Key;
     24 import java.security.spec.AlgorithmParameterSpec;
     25 
     26 /**
     27  * The <i>Service Provider Interface</i> (<b>SPI</b>) definition for the {@code
     28  * ExemptionMechanism} class.
     29  */
     30 public abstract class ExemptionMechanismSpi {
     31 
     32     /**
     33      * Creates a new {@code ExemptionMechanismSpi} instance.
     34      */
     35     public ExemptionMechanismSpi() {
     36     }
     37 
     38     /**
     39      * Generates the result key blob for this exemption mechanism.
     40      *
     41      * @return the result key blob for this exemption mechanism.
     42      * @throws ExemptionMechanismException
     43      *             if error(s) occur during generation.
     44      */
     45     protected abstract byte[] engineGenExemptionBlob()
     46             throws ExemptionMechanismException;
     47 
     48     /**
     49      * Generates the result key blob for this exemption mechanism and stores it
     50      * into the {@code output} buffer at offset {@code outputOffset}.
     51      *
     52      * @param output
     53      *            the output buffer for the result key blob.
     54      * @param outputOffset
     55      *            the offset in the output buffer to start.
     56      * @return the number of bytes written to the {@code output} buffer.
     57      * @throws ShortBufferException
     58      *             if the provided buffer is too small for the result key blob.
     59      * @throws ExemptionMechanismException
     60      *             if error(s) occur during generation.
     61      */
     62     protected abstract int engineGenExemptionBlob(byte[] output,
     63             int outputOffset) throws ShortBufferException,
     64             ExemptionMechanismException;
     65 
     66     /**
     67      * Returns the size in bytes for the output buffer needed to hold the output
     68      * of the next {@link #engineGenExemptionBlob} call, given the specified
     69      * {@code inputLen} (in bytes).
     70      *
     71      * @param inputLen
     72      *            the specified input length (in bytes).
     73      * @return the size in bytes for the output buffer.
     74      */
     75     protected abstract int engineGetOutputSize(int inputLen);
     76 
     77     /**
     78      * Initializes this {@code ExemptionMechanism} instance with the specified
     79      * key.
     80      *
     81      * @param key
     82      *            the key to initialize this instance with.
     83      * @throws InvalidKeyException
     84      *             if the key cannot be used to initialize this mechanism.
     85      * @throws ExemptionMechanismException
     86      *             if error(s) occur during initialization.
     87      */
     88     protected abstract void engineInit(Key key) throws InvalidKeyException,
     89             ExemptionMechanismException;
     90 
     91     /**
     92      * Initializes this {@code ExemptionMechanism} instance with the specified
     93      * key and algorithm parameters.
     94      *
     95      * @param key
     96      *            the key to initialize this instance with.
     97      * @param params
     98      *            the parameters for this exemption mechanism algorithm.
     99      * @throws InvalidKeyException
    100      *             if the key cannot be used to initialize this mechanism.
    101      * @throws InvalidAlgorithmParameterException
    102      *             if the parameters cannot be used to initialize this
    103      *             mechanism.
    104      * @throws ExemptionMechanismException
    105      *             if error(s) occur during initialization.
    106      */
    107     protected abstract void engineInit(Key key, AlgorithmParameters params)
    108             throws InvalidKeyException, InvalidAlgorithmParameterException,
    109             ExemptionMechanismException;
    110 
    111     /**
    112      * Initializes this {@code ExemptionMechanism} instance with the specified
    113      * key and algorithm parameters.
    114      *
    115      * @param key
    116      *            the key to initialize this instance with.
    117      * @param params
    118      *            the parameters for this exemption mechanism algorithm.
    119      * @throws InvalidKeyException
    120      *             if the key cannot be used to initialize this mechanism.
    121      * @throws InvalidAlgorithmParameterException
    122      *             the the parameters cannot be used to initialize this
    123      *             mechanism.
    124      * @throws ExemptionMechanismException
    125      *             if error(s) occur during initialization.
    126      */
    127     protected abstract void engineInit(Key key, AlgorithmParameterSpec params)
    128             throws InvalidKeyException, InvalidAlgorithmParameterException,
    129             ExemptionMechanismException;
    130 }