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25 
26 package sun.security.action;
27 
28 import java.security.AccessController;
29 import java.security.PrivilegedAction;
30 import java.util.Properties;
31 
32 /**
33  * A convenience class for retrieving the string value of a system
34  * property as a privileged action.
35  *
36  * <p>An instance of this class can be used as the argument of
37  * <code>AccessController.doPrivileged</code>.
38  *
39  * <p>The following code retrieves the value of the system
40  * property named <code>"prop"</code> as a privileged action:
41  *
42  * <pre>
43  * String s = java.security.AccessController.doPrivileged
44  *                      (new GetPropertyAction("prop"));
45  * </pre>
46  *
47  * @author Roland Schemers
48  * @see java.security.PrivilegedAction
49  * @see java.security.AccessController
50  * @since 1.2
51  */
52 
53 public class GetPropertyAction implements PrivilegedAction<String> {
54     private String theProp;
55     private String defaultVal;
56 
57     /**
58      * Constructor that takes the name of the system property whose
59      * string value needs to be determined.
60      *
61      * @param theProp the name of the system property.
62      */
GetPropertyAction(String theProp)63     public GetPropertyAction(String theProp) {
64         this.theProp = theProp;
65     }
66 
67     /**
68      * Constructor that takes the name of the system property and the default
69      * value of that property.
70      *
71      * @param theProp the name of the system property.
72      * @param defaultVal the default value.
73      */
GetPropertyAction(String theProp, String defaultVal)74     public GetPropertyAction(String theProp, String defaultVal) {
75         this.theProp = theProp;
76         this.defaultVal = defaultVal;
77     }
78 
79     /**
80      * Determines the string value of the system property whose
81      * name was specified in the constructor.
82      *
83      * @return the string value of the system property,
84      *         or the default value if there is no property with that key.
85      */
run()86     public String run() {
87         String value = System.getProperty(theProp);
88         return (value == null) ? defaultVal : value;
89     }
90 
91     /**
92      * Convenience method to get a property without going through doPrivileged
93      * if no security manager is present. This is unsafe for inclusion in a
94      * public API but allowable here since this class is now encapsulated.
95      *
96      * Note that this method performs a privileged action using caller-provided
97      * inputs. The caller of this method should take care to ensure that the
98      * inputs are not tainted and the returned property is not made accessible
99      * to untrusted code if it contains sensitive information.
100      *
101      * @param theProp the name of the system property.
102      */
103     @SuppressWarnings("removal")
privilegedGetProperty(String theProp)104     public static String privilegedGetProperty(String theProp) {
105         if (System.getSecurityManager() == null) {
106             return System.getProperty(theProp);
107         } else {
108             return AccessController.doPrivileged(
109                     new GetPropertyAction(theProp));
110         }
111     }
112 
113     /**
114      * Convenience method to get a property without going through doPrivileged
115      * if no security manager is present. This is unsafe for inclusion in a
116      * public API but allowable here since this class is now encapsulated.
117      *
118      * Note that this method performs a privileged action using caller-provided
119      * inputs. The caller of this method should take care to ensure that the
120      * inputs are not tainted and the returned property is not made accessible
121      * to untrusted code if it contains sensitive information.
122      *
123      * @param theProp the name of the system property.
124      * @param defaultVal the default value.
125      */
126     @SuppressWarnings("removal")
privilegedGetProperty(String theProp, String defaultVal)127     public static String privilegedGetProperty(String theProp,
128             String defaultVal) {
129         if (System.getSecurityManager() == null) {
130             return System.getProperty(theProp, defaultVal);
131         } else {
132             return AccessController.doPrivileged(
133                     new GetPropertyAction(theProp, defaultVal));
134         }
135     }
136 
137     /**
138      * Convenience method to call <code>System.getProperties</code> without
139      * having to go through doPrivileged if no security manager is present.
140      * This is unsafe for inclusion in a public API but allowable here since
141      * this class is now encapsulated.
142      *
143      * Note that this method performs a privileged action, and callers of
144      * this method should take care to ensure that the returned properties
145      * are not made accessible to untrusted code since it may contain
146      * sensitive information.
147      */
148     @SuppressWarnings("removal")
privilegedGetProperties()149     public static Properties privilegedGetProperties() {
150         if (System.getSecurityManager() == null) {
151             return System.getProperties();
152         } else {
153             return AccessController.doPrivileged(
154                     new PrivilegedAction<Properties>() {
155                         public Properties run() {
156                             return System.getProperties();
157                         }
158                     }
159             );
160         }
161     }
162 }
163