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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  * However, note that defaults may vary across different providers.
43  * Additionally, the default value for a provider may change in a future
44  * version. Therefore, it is recommended to explicitly initialize the
45  * AlgorithmParameterGenerator instead of relying on provider-specific defaults.
46  *
47  * @author Jan Luehe
48  *
49  *
50  * @see AlgorithmParameterGenerator
51  * @see AlgorithmParameters
52  * @see java.security.spec.AlgorithmParameterSpec
53  *
54  * @since 1.2
55  */
56 
57 public abstract class AlgorithmParameterGeneratorSpi {
58 
59     /**
60      * Initializes this parameter generator for a certain size
61      * and source of randomness.
62      *
63      * @param size the size (number of bits).
64      * @param random the source of randomness.
65      */
engineInit(int size, SecureRandom random)66     protected abstract void engineInit(int size, SecureRandom random);
67 
68     /**
69      * Initializes this parameter generator with a set of
70      * algorithm-specific parameter generation values.
71      *
72      * @param genParamSpec the set of algorithm-specific parameter generation values.
73      * @param random the source of randomness.
74      *
75      * @exception InvalidAlgorithmParameterException if the given parameter
76      * generation values are inappropriate for this parameter generator.
77      */
engineInit(AlgorithmParameterSpec genParamSpec, SecureRandom random)78     protected abstract void engineInit(AlgorithmParameterSpec genParamSpec,
79                                        SecureRandom random)
80         throws InvalidAlgorithmParameterException;
81 
82     /**
83      * Generates the parameters.
84      *
85      * @return the new AlgorithmParameters object.
86      */
engineGenerateParameters()87     protected abstract AlgorithmParameters engineGenerateParameters();
88 }
89