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25 
26 package java.security.spec;
27 
28 /**
29  * This class represents a public or private key in encoded format.
30  *
31  * @author Jan Luehe
32  *
33  *
34  * @see java.security.Key
35  * @see java.security.KeyFactory
36  * @see KeySpec
37  * @see X509EncodedKeySpec
38  * @see PKCS8EncodedKeySpec
39  *
40  * @since 1.2
41  */
42 
43 public abstract class EncodedKeySpec implements KeySpec {
44 
45     private byte[] encodedKey;
46     private String algorithmName;
47 
48     /**
49      * Creates a new {@code EncodedKeySpec} with the given encoded key.
50      *
51      * @param encodedKey the encoded key. The contents of the
52      * array are copied to protect against subsequent modification.
53      * @throws NullPointerException if {@code encodedKey}
54      * is null.
55      */
EncodedKeySpec(byte[] encodedKey)56     public EncodedKeySpec(byte[] encodedKey) {
57         this.encodedKey = encodedKey.clone();
58     }
59 
60     /**
61      * Creates a new {@code EncodedKeySpec} with the given encoded key.
62      * This constructor is useful when subsequent callers of the
63      * {@code EncodedKeySpec} object might not know the algorithm
64      * of the key.
65      *
66      * @param encodedKey the encoded key. The contents of the
67      * array are copied to protect against subsequent modification.
68      * @param algorithm the algorithm name of the encoded key
69      * See the KeyFactory section in the <a href=
70      * "{@docRoot}/../specs/security/standard-names.html#keyfactory-algorithms">
71      * Java Security Standard Algorithm Names Specification</a>
72      * for information about standard algorithm names.
73      * @throws NullPointerException if {@code encodedKey}
74      * or {@code algorithm} is null.
75      * @throws IllegalArgumentException if {@code algorithm} is
76      * the empty string {@code ""}
77      * @since 9
78      */
EncodedKeySpec(byte[] encodedKey, String algorithm)79     protected EncodedKeySpec(byte[] encodedKey, String algorithm) {
80         if (algorithm == null) {
81             throw new NullPointerException("algorithm name may not be null");
82         }
83         if (algorithm.isEmpty()) {
84             throw new IllegalArgumentException("algorithm name "
85                                              + "may not be empty");
86         }
87         this.encodedKey = encodedKey.clone();
88         this.algorithmName = algorithm;
89 
90     }
91 
92     /**
93      * Returns the name of the algorithm of the encoded key.
94      *
95      * @return the name of the algorithm, or null if not specified
96      * @since 9
97      */
getAlgorithm()98     public String getAlgorithm() {
99         return algorithmName;
100     }
101 
102     /**
103      * Returns the encoded key.
104      *
105      * @return the encoded key. Returns a new array each time
106      * this method is called.
107      */
getEncoded()108     public byte[] getEncoded() {
109         return this.encodedKey.clone();
110     }
111 
112     /**
113      * Returns the name of the encoding format associated with this
114      * key specification.
115      *
116      * <p>If the opaque representation of a key
117      * (see {@link java.security.Key Key}) can be transformed
118      * (see {@link java.security.KeyFactory KeyFactory})
119      * into this key specification (or a subclass of it),
120      * {@code getFormat} called
121      * on the opaque key returns the same value as the
122      * {@code getFormat} method
123      * of this key specification.
124      *
125      * @return a string representation of the encoding format.
126      */
getFormat()127     public abstract String getFormat();
128 }
129