1 /*
   2  * Copyright (c) 1997, 2019, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
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  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
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  17  * You should have received a copy of the GNU General Public License version
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  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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  23  * questions.
  24  */
  25 
  26 package java.security;
  27 
  28 import java.security.spec.AlgorithmParameterSpec;
  29 
  30 /**
  31  * This class defines the <i>Service Provider Interface</i> (<b>SPI</b>)
  32  * for the {@code AlgorithmParameterGenerator} class, which
  33  * is used to generate a set of parameters to be used with a certain algorithm.
  34  *
  35  * <p> All the abstract methods in this class must be implemented by each
  36  * cryptographic service provider who wishes to supply the implementation
  37  * of a parameter generator for a particular algorithm.
  38  *
  39  * <p> In case the client does not explicitly initialize the
  40  * AlgorithmParameterGenerator (via a call to an {@code engineInit}
  41  * method), each provider must supply (and document) a default initialization.
  42  * See the Keysize Restriction sections of the
  43  * {@extLink security_guide_jdk_providers JDK Providers}
  44  * document for information on the AlgorithmParameterGenerator defaults
  45  * used by JDK providers.
  46  * However, note that defaults may vary across different providers.
  47  * Additionally, the default value for a provider may change in a future
  48  * version. Therefore, it is recommended to explicitly initialize the
  49  * AlgorithmParameterGenerator instead of relying on provider-specific defaults.
  50  *
  51  * @author Jan Luehe
  52  *
  53  *
  54  * @see AlgorithmParameterGenerator
  55  * @see AlgorithmParameters
  56  * @see java.security.spec.AlgorithmParameterSpec
  57  *
  58  * @since 1.2
  59  */
  60 
  61 public abstract class AlgorithmParameterGeneratorSpi {
  62 
  63     /**
  64      * Initializes this parameter generator for a certain size
  65      * and source of randomness.
  66      *
  67      * @param size the size (number of bits).
  68      * @param random the source of randomness.
  69      */
  70     protected abstract void engineInit(int size, SecureRandom random);
  71 
  72     /**
  73      * Initializes this parameter generator with a set of
  74      * algorithm-specific parameter generation values.
  75      *
  76      * @param genParamSpec the set of algorithm-specific parameter generation values.
  77      * @param random the source of randomness.
  78      *
  79      * @throws    InvalidAlgorithmParameterException if the given parameter
  80      * generation values are inappropriate for this parameter generator.
  81      */
  82     protected abstract void engineInit(AlgorithmParameterSpec genParamSpec,
  83                                        SecureRandom random)
  84         throws InvalidAlgorithmParameterException;
  85 
  86     /**
  87      * Generates the parameters.
  88      *
  89      * @return the new AlgorithmParameters object.
  90      */
  91     protected abstract AlgorithmParameters engineGenerateParameters();
  92 }