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1   /*
2    * Copyright (c) 1998, 2006, Oracle and/or its affiliates. All rights reserved.
3    * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4    *
5    * This code is free software; you can redistribute it and/or modify it
6    * under the terms of the GNU General Public License version 2 only, as
7    * published by the Free Software Foundation.  Oracle designates this
8    * particular file as subject to the "Classpath" exception as provided
9    * by Oracle in the LICENSE file that accompanied this code.
10   *
11   * This code is distributed in the hope that it will be useful, but WITHOUT
12   * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13   * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14   * version 2 for more details (a copy is included in the LICENSE file that
15   * accompanied this code).
16   *
17   * You should have received a copy of the GNU General Public License version
18   * 2 along with this work; if not, write to the Free Software Foundation,
19   * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20   *
21   * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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24   */
25  
26  package sun.security.action;
27  
28  /**
29   * A convenience class for retrieving the string value of a system
30   * property as a privileged action.
31   *
32   * <p>An instance of this class can be used as the argument of
33   * <code>AccessController.doPrivileged</code>.
34   *
35   * <p>The following code retrieves the value of the system
36   * property named <code>"prop"</code> as a privileged action: <p>
37   *
38   * <pre>
39   * String s = java.security.AccessController.doPrivileged
40   *                      (new GetPropertyAction("prop"));
41   * </pre>
42   *
43   * @author Roland Schemers
44   * @see java.security.PrivilegedAction
45   * @see java.security.AccessController
46   * @since 1.2
47   */
48  
49  public class GetPropertyAction
50          implements java.security.PrivilegedAction<String> {
51      private String theProp;
52      private String defaultVal;
53  
54      /**
55       * Constructor that takes the name of the system property whose
56       * string value needs to be determined.
57       *
58       * @param theProp the name of the system property.
59       */
60      public GetPropertyAction(String theProp) {
61          this.theProp = theProp;
62      }
63  
64      /**
65       * Constructor that takes the name of the system property and the default
66       * value of that property.
67       *
68       * @param theProp the name of the system property.
69       * @param defaulVal the default value.
70       */
71      public GetPropertyAction(String theProp, String defaultVal) {
72          this.theProp = theProp;
73          this.defaultVal = defaultVal;
74      }
75  
76      /**
77       * Determines the string value of the system property whose
78       * name was specified in the constructor.
79       *
80       * @return the string value of the system property,
81       *         or the default value if there is no property with that key.
82       */
83      public String run() {
84          String value = System.getProperty(theProp);
85          return (value == null) ? defaultVal : value;
86      }
87  }