1 /*
   2  * Copyright (c) 2007,2011, 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 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      */
  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 }