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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 org.apache.harmony.luni.util;
     19 
     20 
     21 import java.lang.reflect.AccessibleObject;
     22 import java.security.Policy;
     23 import java.security.PrivilegedAction;
     24 import java.security.Security;
     25 
     26 /**
     27  * Helper class to avoid multiple anonymous inner class for
     28  * <code>{@link java.security.AccessController#doPrivileged(PrivilegedAction)}</code>
     29  * calls.
     30  */
     31 public class PriviAction<T> implements PrivilegedAction<T> {
     32 
     33     private Object arg1;
     34 
     35     private Object arg2;
     36 
     37     private int action;
     38 
     39     private static final int GET_SYSTEM_PROPERTY = 1;
     40 
     41     private static final int GET_SECURITY_POLICY = 2;
     42 
     43     private static final int SET_ACCESSIBLE = 3;
     44 
     45     private static final int GET_SECURITY_PROPERTY = 4;
     46 
     47     /**
     48      * Creates a PrivilegedAction to get the security property with the given
     49      * name.
     50      *
     51      * @param property
     52      *            the name of the property
     53      *
     54      * @see Security#getProperty
     55      */
     56     public static PrivilegedAction<String> getSecurityProperty(String property) {
     57         return new PriviAction<String>(GET_SECURITY_PROPERTY, property);
     58     }
     59 
     60     private PriviAction(int action, Object arg) {
     61         this.action = action;
     62         this.arg1 = arg;
     63     }
     64 
     65     /**
     66      * Creates a PrivilegedAction to get the current security policy object.
     67      *
     68      * @see Policy#getPolicy
     69      */
     70     public PriviAction() {
     71         action = GET_SECURITY_POLICY;
     72     }
     73 
     74     /**
     75      * Creates a PrivilegedAction to disable the access checks to the given
     76      * object.
     77      *
     78      * @param object
     79      *            the object whose accessible flag will be set to
     80      *            <code>true</code>
     81      *
     82      * @see AccessibleObject#setAccessible(boolean)
     83      */
     84     public PriviAction(AccessibleObject object) {
     85         action = SET_ACCESSIBLE;
     86         arg1 = object;
     87     }
     88 
     89     /**
     90      * Creates a PrivilegedAction to return the value of the system property
     91      * with the given key.
     92      *
     93      * @param property
     94      *            the key of the system property
     95      *
     96      * @see System#getProperty(String)
     97      */
     98     public PriviAction(String property) {
     99         action = GET_SYSTEM_PROPERTY;
    100         arg1 = property;
    101     }
    102 
    103     /**
    104      * Creates a PrivilegedAction to return the value of the system property
    105      * with the given key.
    106      *
    107      * @param property
    108      *            the key of the system property
    109      * @param defaultAnswer
    110      *            the return value if the system property does not exist
    111      *
    112      * @see System#getProperty(String, String)
    113      */
    114     public PriviAction(String property, String defaultAnswer) {
    115         action = GET_SYSTEM_PROPERTY;
    116         arg1 = property;
    117         arg2 = defaultAnswer;
    118     }
    119 
    120     /**
    121      * Performs the actual privileged computation as defined by the constructor.
    122      *
    123      * @see java.security.PrivilegedAction#run()
    124      */
    125     @SuppressWarnings("unchecked")
    126     public T run() {
    127         switch (action) {
    128         case GET_SYSTEM_PROPERTY:
    129             return (T)System.getProperty((String) arg1, (String) arg2);
    130         case GET_SECURITY_PROPERTY:
    131             return (T)Security.getProperty((String) arg1);
    132         case GET_SECURITY_POLICY:
    133             return (T)Policy.getPolicy();
    134         case SET_ACCESSIBLE:
    135             ((AccessibleObject) arg1).setAccessible(true);
    136         }
    137         return null;
    138     }
    139 }
    140