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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
     22  * or visit www.oracle.com if you need additional information or have any
     23  * questions.
     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 }
     88