1 /*
   2  * Copyright (c) 2007, 2019, 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 java.net;
  27 
  28 import sun.security.action.GetPropertyAction;
  29 
  30 /**
  31  * This class defines a factory for creating DatagramSocketImpls. It defaults
  32  * to creating plain DatagramSocketImpls, but may create other DatagramSocketImpls
  33  * by setting the impl.prefix system property.
  34  *
  35  * @author Chris Hegarty
  36  */
  37 
  38 class DefaultDatagramSocketImplFactory {
  39     static Class<?> prefixImplClass = null;
  40 
  41     static {
  42         String prefix = null;
  43         try {
  44             prefix = GetPropertyAction.privilegedGetProperty("impl.prefix");
  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                 @SuppressWarnings("deprecation")
  66                 DatagramSocketImpl result = (DatagramSocketImpl)prefixImplClass.newInstance();
  67                 return result;
  68             } catch (Exception e) {
  69                 throw new SocketException("can't instantiate DatagramSocketImpl");
  70             }
  71         } else {
  72             return new java.net.PlainDatagramSocketImpl(isMulticast);
  73         }
  74     }
  75 }