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 sun.security.action.GetPropertyAction;
  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 = GetPropertyAction.getProperty("impl.prefix", null);
  44             if (prefix != null)
  45                 prefixImplClass = Class.forName("java.net."+prefix+"DatagramSocketImpl");
  46         } catch (Exception e) {
  47             System.err.println("Can't find class: java.net." +
  48                                 prefix +
  49                                 "DatagramSocketImpl: check impl.prefix property");
  50             //prefixImplClass = null;
  51         }
  52     }
  53 
  54     /**
  55      * Creates a new <code>DatagramSocketImpl</code> instance.
  56      *
  57      * @param   isMulticast     true if this impl if for a MutlicastSocket
  58      * @return  a new instance of a <code>DatagramSocketImpl</code>.
  59      */
  60     static DatagramSocketImpl createDatagramSocketImpl(boolean isMulticast /*unused on unix*/)
  61         throws SocketException {
  62         if (prefixImplClass != null) {
  63             try {
  64                 return (DatagramSocketImpl)prefixImplClass.newInstance();
  65             } catch (Exception e) {
  66                 throw new SocketException("can't instantiate DatagramSocketImpl");
  67             }
  68         } else {
  69             return new java.net.PlainDatagramSocketImpl();
  70         }
  71     }
  72 }