1 /*
   2  * Copyright (c) 2016, 2017, 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 javax.xml.soap;
  27 
  28 import java.util.ServiceLoader;
  29 import java.util.logging.Level;
  30 import java.util.logging.Logger;
  31 
  32 /**
  33  * Shared ServiceLoader/FactoryFinder Utils shared among SAAJ, JAXB and JAXWS
  34  * Class duplicated to all those projects.
  35  *
  36  * @author Miroslav.Kos@oracle.com
  37  */
  38 class ServiceLoaderUtil {
  39 
  40     static <P, T extends Exception> P firstByServiceLoader(Class<P> spiClass,
  41                                                            Logger logger,
  42                                                            ExceptionHandler<T> handler) throws T {
  43         logger.log(Level.FINE, "Using java.util.ServiceLoader to find {0}", spiClass.getName());
  44         // service discovery
  45         try {
  46             ServiceLoader<P> serviceLoader = ServiceLoader.load(spiClass);
  47 
  48             for (P impl : serviceLoader) {
  49                 logger.log(Level.FINE, "ServiceProvider loading Facility used; returning object [{0}]", impl.getClass().getName());

  50 
  51                 return impl;
  52             }
  53         } catch (Throwable t) {
  54             throw handler.createException(t, "Error while searching for service [" + spiClass.getName() + "]");
  55         }
  56         return null;
  57     }
  58 
  59     static void checkPackageAccess(String className) {
  60         // make sure that the current thread has an access to the package of the given name.
  61         SecurityManager s = System.getSecurityManager();
  62         if (s != null) {
  63             int i = className.lastIndexOf('.');
  64             if (i != -1) {
  65                 s.checkPackageAccess(className.substring(0, i));
  66             }
  67         }
  68     }
  69 
  70     static Class nullSafeLoadClass(String className, ClassLoader classLoader) throws ClassNotFoundException {
  71         if (classLoader == null) {
  72             return Class.forName(className);
  73         } else {
  74             return classLoader.loadClass(className);
  75         }
  76     }
  77 
  78     // Returns instance of required class. It checks package access (security)
  79     // unless it is defaultClassname. It means if you are trying to instantiate
  80     // default implementation (fallback), pass the class name to both first and second parameter.
  81     static <T extends Exception> Object newInstance(String className,
  82                                                     String defaultImplClassName, ClassLoader classLoader,
  83                                                     final ExceptionHandler<T> handler) throws T {
  84         try {
  85             return safeLoadClass(className, defaultImplClassName, classLoader).newInstance();
  86         } catch (ClassNotFoundException x) {
  87             throw handler.createException(x, "Provider " + className + " not found");
  88         } catch (Exception x) {
  89             throw handler.createException(x, "Provider " + className + " could not be instantiated: " + x);
  90         }
  91     }
  92 
  93     static Class safeLoadClass(String className,
  94                                String defaultImplClassName,
  95                                ClassLoader classLoader) throws ClassNotFoundException {
  96 
  97         try {
  98             checkPackageAccess(className);
  99         } catch (SecurityException se) {
 100             // anyone can access the platform default factory class without permission
 101             if (defaultImplClassName != null && defaultImplClassName.equals(className)) {
 102                 return Class.forName(className);
 103             }
 104             // not platform default implementation ...
 105             throw se;
 106         }
 107         return nullSafeLoadClass(className, classLoader);
 108     }
 109 
 110     static <T extends Exception> ClassLoader contextClassLoader(ExceptionHandler<T> exceptionHandler) throws T {
 111         try {
 112             return Thread.currentThread().getContextClassLoader();
 113         } catch (Exception x) {
 114             throw exceptionHandler.createException(x, x.toString());
 115         }
 116     }
 117 
 118     static abstract class ExceptionHandler<T extends Exception> {
 119 
 120         public abstract T createException(Throwable throwable, String message);
 121 
 122     }
 123 
 124 }
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