1 /*
   2  * Copyright (c) 2014, 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 com.sun.xml.internal.messaging.saaj.soap;
  27 
  28 import java.security.AccessController;
  29 import java.security.PrivilegedAction;
  30 import java.text.MessageFormat;
  31 import java.util.ResourceBundle;
  32 import java.util.WeakHashMap;
  33 
  34 /**
  35  * Simple utility ensuring that the value is cached only in case it is non-internal implementation
  36  */
  37 abstract class ContextClassloaderLocal<V> {
  38 
  39     private static final String FAILED_TO_CREATE_NEW_INSTANCE = "FAILED_TO_CREATE_NEW_INSTANCE";
  40 
  41     private WeakHashMap<ClassLoader, V> CACHE = new WeakHashMap<ClassLoader, V>();
  42 
  43     public V get() throws Error {
  44         ClassLoader tccl = getContextClassLoader();
  45         V instance = CACHE.get(tccl);
  46         if (instance == null) {
  47             instance = createNewInstance();
  48             CACHE.put(tccl, instance);
  49         }
  50         return instance;
  51     }
  52 
  53     public void set(V instance) {
  54         CACHE.put(getContextClassLoader(), instance);
  55     }
  56 
  57     protected abstract V initialValue() throws Exception;
  58 
  59     private V createNewInstance() {
  60         try {
  61             return initialValue();
  62         } catch (Exception e) {
  63             throw new Error(format(FAILED_TO_CREATE_NEW_INSTANCE, getClass().getName()), e);
  64         }
  65     }
  66 
  67     private static String format(String property, Object... args) {
  68         String text = ResourceBundle.getBundle(ContextClassloaderLocal.class.getName()).getString(property);
  69         return MessageFormat.format(text, args);
  70     }
  71 
  72     private static ClassLoader getContextClassLoader() {
  73         return (ClassLoader)
  74                 AccessController.doPrivileged(new PrivilegedAction() {
  75                     public Object run() {
  76                         ClassLoader cl = null;
  77                         try {
  78                             cl = Thread.currentThread().getContextClassLoader();
  79                         } catch (SecurityException ex) {
  80                         }
  81                         return cl;
  82                     }
  83                 });
  84     }
  85 }
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