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      1 /*
      2  *  Licensed to the Apache Software Foundation (ASF) under one or more
      3  *  contributor license agreements.  See the NOTICE file distributed with
      4  *  this work for additional information regarding copyright ownership.
      5  *  The ASF licenses this file to You under the Apache License, Version 2.0
      6  *  (the "License"); you may not use this file except in compliance with
      7  *  the License.  You may obtain a copy of the License at
      8  *
      9  *     http://www.apache.org/licenses/LICENSE-2.0
     10  *
     11  *  Unless required by applicable law or agreed to in writing, software
     12  *  distributed under the License is distributed on an "AS IS" BASIS,
     13  *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     14  *  See the License for the specific language governing permissions and
     15  *  limitations under the License.
     16  */
     17 
     18 package java.security;
     19 
     20 /**
     21  * Represents the Service Provider Interface (SPI) for java.security.Policy
     22  * class.
     23  *
     24  * <p>If there is any class that wants to provide a Policy implementation, all
     25  * abstract methods in this SPI should be implemented.
     26  *
     27  * <p>The detailed implementations should offer a public constructor, in which a
     28  * Policy.Paramters implementation acts as an input parameter.If the
     29  * Policy.Paramters input cannot by understood by the constructor, an
     30  * IllegalArgumentException will be thrown.
     31  */
     32 public abstract class PolicySpi {
     33 
     34     public PolicySpi() {
     35         // default constructor
     36     }
     37 
     38     /**
     39      * Answers if the policy has granted a Permission to a
     40      * ProtectionDomain.
     41      *
     42      * @param domain -
     43      *            the domain to check.
     44      * @param permission -
     45      *            check whether this permission is granted to the specified
     46      *            domain.
     47      * @return - true if the permission is granted to the domain.
     48      *
     49      */
     50     protected abstract boolean engineImplies(ProtectionDomain domain,
     51             Permission permission);
     52 
     53     /**
     54      * Refreshes/reloads the policy configuration. The behavior of this method
     55      * depends on the implementation. For example, calling refresh on a
     56      * file-based policy will cause the file to be re-read.
     57      *
     58      * The default implementation of this method does nothing. This method
     59      * should be overridden if a refresh operation is supported by the policy
     60      * implementation.
     61      *
     62      */
     63     protected void engineRefresh() {
     64         // do nothing in default implementation
     65     }
     66 
     67     /**
     68      * Answers a PermissionCollection object containing the set of permissions
     69      * granted to the specified CodeSource.
     70      *
     71      * The default implementation of this method returns
     72      * Policy.UNSUPPORTED_EMPTY_COLLECTION object. This method can be overridden
     73      * if the policy implementation can return a set of permissions granted to a
     74      * CodeSource.
     75      *
     76      * @param codesource -
     77      *            the CodeSource to which the returned PermissionCollection has
     78      *            been granted.
     79      * @return a set of permissions granted to the specified CodeSource. If this
     80      *         operation is supported, the returned set of permissions must be a
     81      *         new mutable instance and it must support heterogeneous Permission
     82      *         types. If this operation is not supported,
     83      *         Policy.UNSUPPORTED_EMPTY_COLLECTION is returned.
     84      */
     85     protected PermissionCollection engineGetPermissions(CodeSource codesource) {
     86         return Policy.UNSUPPORTED_EMPTY_COLLECTION;
     87     }
     88 
     89     /**
     90      * Answers a PermissionCollection object containing the set of permissions
     91      * granted to the specified ProtectionDomain.
     92      *
     93      * The default implementation of this method returns
     94      * Policy.UNSUPPORTED_EMPTY_COLLECTION object. This method can be overridden
     95      * if the policy implementation can return a set of permissions granted to a
     96      * ProtectionDomain.
     97      *
     98      * @param domain -
     99      *            the ProtectionDomain to which the returned
    100      *            PermissionCollection has been granted.
    101      * @return a set of permissions granted to the specified ProtectionDomain.
    102      *         If this operation is supported, the returned set of permissions
    103      *         must be a new mutable instance and it must support heterogeneous
    104      *         Permission types. If this operation is not supported,
    105      *         Policy.UNSUPPORTED_EMPTY_COLLECTION is returned.
    106      */
    107     protected PermissionCollection engineGetPermissions(ProtectionDomain domain) {
    108         return Policy.UNSUPPORTED_EMPTY_COLLECTION;
    109     }
    110 }
    111