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25 
26 package java.security;
27 
28 import java.io.*;
29 import java.security.spec.AlgorithmParameterSpec;
30 import java.security.spec.InvalidParameterSpecException;
31 
32 /**
33  * This class defines the <i>Service Provider Interface</i> (<b>SPI</b>)
34  * for the {@code AlgorithmParameters} class, which is used to manage
35  * algorithm parameters.
36  *
37  * <p> All the abstract methods in this class must be implemented by each
38  * cryptographic service provider who wishes to supply parameter management
39  * for a particular algorithm.
40  *
41  * @author Jan Luehe
42  *
43  *
44  * @see AlgorithmParameters
45  * @see java.security.spec.AlgorithmParameterSpec
46  * @see java.security.spec.DSAParameterSpec
47  *
48  * @since 1.2
49  */
50 
51 public abstract class AlgorithmParametersSpi {
52 
53     /**
54      * Initializes this parameters object using the parameters
55      * specified in {@code paramSpec}.
56      *
57      * @param paramSpec the parameter specification.
58      *
59      * @exception InvalidParameterSpecException if the given parameter
60      * specification is inappropriate for the initialization of this parameter
61      * object.
62      */
engineInit(AlgorithmParameterSpec paramSpec)63     protected abstract void engineInit(AlgorithmParameterSpec paramSpec)
64         throws InvalidParameterSpecException;
65 
66     /**
67      * Imports the specified parameters and decodes them
68      * according to the primary decoding format for parameters.
69      * The primary decoding format for parameters is ASN.1, if an ASN.1
70      * specification for this type of parameters exists.
71      *
72      * @param params the encoded parameters.
73      *
74      * @exception IOException on decoding errors
75      */
engineInit(byte[] params)76     protected abstract void engineInit(byte[] params)
77         throws IOException;
78 
79     /**
80      * Imports the parameters from {@code params} and
81      * decodes them according to the specified decoding format.
82      * If {@code format} is null, the
83      * primary decoding format for parameters is used. The primary decoding
84      * format is ASN.1, if an ASN.1 specification for these parameters
85      * exists.
86      *
87      * @param params the encoded parameters.
88      *
89      * @param format the name of the decoding format.
90      *
91      * @exception IOException on decoding errors
92      */
engineInit(byte[] params, String format)93     protected abstract void engineInit(byte[] params, String format)
94         throws IOException;
95 
96     /**
97      * Returns a (transparent) specification of this parameters
98      * object.
99      * {@code paramSpec} identifies the specification class in which
100      * the parameters should be returned. It could, for example, be
101      * {@code DSAParameterSpec.class}, to indicate that the
102      * parameters should be returned in an instance of the
103      * {@code DSAParameterSpec} class.
104      *
105      * @param <T> the type of the parameter specification to be returned
106      *
107      * @param paramSpec the specification class in which
108      * the parameters should be returned.
109      *
110      * @return the parameter specification.
111      *
112      * @exception InvalidParameterSpecException if the requested parameter
113      * specification is inappropriate for this parameter object.
114      */
115     protected abstract
116         <T extends AlgorithmParameterSpec>
engineGetParameterSpec(Class<T> paramSpec)117         T engineGetParameterSpec(Class<T> paramSpec)
118         throws InvalidParameterSpecException;
119 
120     /**
121      * Returns the parameters in their primary encoding format.
122      * The primary encoding format for parameters is ASN.1, if an ASN.1
123      * specification for this type of parameters exists.
124      *
125      * @return the parameters encoded using their primary encoding format.
126      *
127      * @exception IOException on encoding errors.
128      */
engineGetEncoded()129     protected abstract byte[] engineGetEncoded() throws IOException;
130 
131     /**
132      * Returns the parameters encoded in the specified format.
133      * If {@code format} is null, the
134      * primary encoding format for parameters is used. The primary encoding
135      * format is ASN.1, if an ASN.1 specification for these parameters
136      * exists.
137      *
138      * @param format the name of the encoding format.
139      *
140      * @return the parameters encoded using the specified encoding scheme.
141      *
142      * @exception IOException on encoding errors.
143      */
engineGetEncoded(String format)144     protected abstract byte[] engineGetEncoded(String format)
145         throws IOException;
146 
147     /**
148      * Returns a formatted string describing the parameters.
149      *
150      * @return a formatted string describing the parameters.
151      */
engineToString()152     protected abstract String engineToString();
153 }
154