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25 
26 
27 package java.security;
28 
29 /**
30  * This class defines the <i>Service Provider Interface</i> (<b>SPI</b>)
31  * for the {@code Policy} class.
32  * All the abstract methods in this class must be implemented by each
33  * service provider who wishes to supply a Policy implementation.
34  *
35  * <p> Subclass implementations of this abstract class must provide
36  * a public constructor that takes a {@code Policy.Parameters}
37  * object as an input parameter.  This constructor also must throw
38  * an IllegalArgumentException if it does not understand the
39  * {@code Policy.Parameters} input.
40  *
41  *
42  * @since 1.6
43  */
44 
45 public abstract class PolicySpi {
46 
47     /**
48      * Check whether the policy has granted a Permission to a ProtectionDomain.
49      *
50      * @param domain the ProtectionDomain to check.
51      *
52      * @param permission check whether this permission is granted to the
53      *          specified domain.
54      *
55      * @return boolean true if the permission is granted to the domain.
56      */
engineImplies(ProtectionDomain domain, Permission permission)57     protected abstract boolean engineImplies
58         (ProtectionDomain domain, Permission permission);
59 
60     /**
61      * Refreshes/reloads the policy configuration. The behavior of this method
62      * depends on the implementation. For example, calling {@code refresh}
63      * on a file-based policy will cause the file to be re-read.
64      *
65      * <p> The default implementation of this method does nothing.
66      * This method should be overridden if a refresh operation is supported
67      * by the policy implementation.
68      */
engineRefresh()69     protected void engineRefresh() { }
70 
71     /**
72      * Return a PermissionCollection object containing the set of
73      * permissions granted to the specified CodeSource.
74      *
75      * <p> The default implementation of this method returns
76      * Policy.UNSUPPORTED_EMPTY_COLLECTION object.  This method can be
77      * overridden if the policy implementation can return a set of
78      * permissions granted to a CodeSource.
79      *
80      * @param codesource the CodeSource to which the returned
81      *          PermissionCollection has been granted.
82      *
83      * @return a set of permissions granted to the specified CodeSource.
84      *          If this operation is supported, the returned
85      *          set of permissions must be a new mutable instance
86      *          and it must support heterogeneous Permission types.
87      *          If this operation is not supported,
88      *          Policy.UNSUPPORTED_EMPTY_COLLECTION is returned.
89      */
engineGetPermissions(CodeSource codesource)90     protected PermissionCollection engineGetPermissions
91                                         (CodeSource codesource) {
92         return Policy.UNSUPPORTED_EMPTY_COLLECTION;
93     }
94 
95     /**
96      * Return a PermissionCollection object containing the set of
97      * permissions granted to the specified ProtectionDomain.
98      *
99      * <p> The default implementation of this method returns
100      * Policy.UNSUPPORTED_EMPTY_COLLECTION object.  This method can be
101      * overridden if the policy implementation can return a set of
102      * permissions granted to a ProtectionDomain.
103      *
104      * @param domain the ProtectionDomain to which the returned
105      *          PermissionCollection has been granted.
106      *
107      * @return a set of permissions granted to the specified ProtectionDomain.
108      *          If this operation is supported, the returned
109      *          set of permissions must be a new mutable instance
110      *          and it must support heterogeneous Permission types.
111      *          If this operation is not supported,
112      *          Policy.UNSUPPORTED_EMPTY_COLLECTION is returned.
113      */
engineGetPermissions(ProtectionDomain domain)114     protected PermissionCollection engineGetPermissions
115                                         (ProtectionDomain domain) {
116         return Policy.UNSUPPORTED_EMPTY_COLLECTION;
117     }
118 }
119