1 /*
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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
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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.
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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
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19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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24  */
25 package java.net;
26 
27 import java.security.AccessController;
28 
29 /**
30  * This class defines a factory for creating DatagramSocketImpls. It defaults
31  * to creating plain DatagramSocketImpls, but may create other DatagramSocketImpls
32  * by setting the impl.prefix system property.
33  *
34  * @author Chris Hegarty
35  */
36 
37 class DefaultDatagramSocketImplFactory {
38     static Class<?> prefixImplClass = null;
39 
40     static {
41         String prefix = null;
42         try {
43             prefix = AccessController.doPrivileged(
44                 new sun.security.action.GetPropertyAction("impl.prefix", null));
45             if (prefix != null)
46                 prefixImplClass = Class.forName("java.net."+prefix+"DatagramSocketImpl");
47         } catch (Exception e) {
48             System.err.println("Can't find class: java.net." +
49                                 prefix +
50                                 "DatagramSocketImpl: check impl.prefix property");
51             //prefixImplClass = null;
52         }
53     }
54 
55     /**
56      * Creates a new <code>DatagramSocketImpl</code> instance.
57      *
58      * @param   isMulticast     true if this impl if for a MutlicastSocket
59      * @return  a new instance of a <code>DatagramSocketImpl</code>.
60      */
createDatagramSocketImpl(boolean isMulticast )61     static DatagramSocketImpl createDatagramSocketImpl(boolean isMulticast /*unused on unix*/)
62         throws SocketException {
63         if (prefixImplClass != null) {
64             try {
65                 return (DatagramSocketImpl)prefixImplClass.newInstance();
66             } catch (Exception e) {
67                 throw new SocketException("can't instantiate DatagramSocketImpl");
68             }
69         } else {
70             return new java.net.PlainDatagramSocketImpl();
71         }
72     }
73 }
74