1 /*
   2  * Copyright (c) 1997, 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 
  26 package com.sun.xml.internal.bind.v2;
  27 
  28 import java.lang.reflect.Constructor;
  29 import java.lang.reflect.InvocationTargetException;
  30 import java.lang.reflect.Method;
  31 import java.lang.reflect.Modifier;
  32 import java.lang.ref.WeakReference;
  33 import java.security.AccessController;
  34 import java.security.PrivilegedAction;
  35 import java.util.Map;
  36 import java.util.WeakHashMap;
  37 import java.util.logging.Level;
  38 import java.util.logging.Logger;
  39 
  40 import com.sun.xml.internal.bind.Util;
  41 
  42 /**
  43  * Creates new instances of classes.
  44  *
  45  * <p>
  46  * This code handles the case where the class is not public or the constructor is
  47  * not public.
  48  *
  49  * @since 2.0
  50  * @author Kohsuke Kawaguchi
  51  */
  52 public final class ClassFactory {
  53     private static final Class[] emptyClass = new Class[0];
  54     private static final Object[] emptyObject = new Object[0];
  55 
  56     private static final Logger logger = Util.getClassLogger();
  57 
  58     /**
  59      * Cache from a class to its default constructor.
  60      *
  61      * To avoid synchronization among threads, we use {@link ThreadLocal}.
  62      */
  63     private static final ThreadLocal<Map<Class, WeakReference<Constructor>>> tls = new ThreadLocal<Map<Class,WeakReference<Constructor>>>() {
  64         @Override
  65         public Map<Class,WeakReference<Constructor>> initialValue() {
  66             return new WeakHashMap<Class,WeakReference<Constructor>>();
  67         }
  68     };
  69 
  70     public static void cleanCache() {
  71         if (tls != null) {
  72             try {
  73                 tls.remove();
  74             } catch (Exception e) {
  75                 logger.log(Level.WARNING, "Unable to clean Thread Local cache of classes used in Unmarshaller: {0}", e.getLocalizedMessage());
  76             }
  77         }
  78     }
  79 
  80     /**
  81      * Creates a new instance of the class but throw exceptions without catching it.
  82      */
  83     public static <T> T create0( final Class<T> clazz ) throws IllegalAccessException, InvocationTargetException, InstantiationException {
  84         Map<Class,WeakReference<Constructor>> m = tls.get();
  85         Constructor<T> cons = null;
  86         WeakReference<Constructor> consRef = m.get(clazz);
  87         if(consRef!=null)
  88             cons = consRef.get();
  89         if(cons==null) {
  90             if (System.getSecurityManager() == null) {
  91                 cons = tryGetDeclaredConstructor(clazz);
  92             } else {
  93                 cons = AccessController.doPrivileged(new PrivilegedAction<Constructor<T>>() {
  94                     @Override
  95                     public Constructor<T> run() {
  96                         return tryGetDeclaredConstructor(clazz);
  97                     }
  98                 });
  99             }
 100 
 101             int classMod = clazz.getModifiers();
 102 
 103             if(!Modifier.isPublic(classMod) || !Modifier.isPublic(cons.getModifiers())) {
 104                 // attempt to make it work even if the constructor is not accessible
 105                 try {
 106                     cons.setAccessible(true);
 107                 } catch(SecurityException e) {
 108                     // but if we don't have a permission to do so, work gracefully.
 109                     logger.log(Level.FINE,"Unable to make the constructor of "+clazz+" accessible",e);
 110                     throw e;
 111                 }
 112             }
 113 
 114             m.put(clazz,new WeakReference<Constructor>(cons));
 115         }
 116         return cons.newInstance(emptyObject);
 117     }
 118 
 119     private static <T> Constructor<T> tryGetDeclaredConstructor(Class<T> clazz) {
 120         try {
 121             return clazz.getDeclaredConstructor((Class<T>[])emptyClass);
 122         } catch (NoSuchMethodException e) {
 123             logger.log(Level.INFO,"No default constructor found on "+clazz,e);
 124             NoSuchMethodError exp;
 125             if(clazz.getDeclaringClass()!=null && !Modifier.isStatic(clazz.getModifiers())) {
 126                 exp = new NoSuchMethodError(Messages.NO_DEFAULT_CONSTRUCTOR_IN_INNER_CLASS
 127                                                     .format(clazz.getName()));
 128             } else {
 129                 exp = new NoSuchMethodError(e.getMessage());
 130             }
 131             exp.initCause(e);
 132             throw exp;
 133         }
 134     }
 135 
 136     /**
 137      * The same as {@link #create0} but with an error handling to make
 138      * the instantiation error fatal.
 139      */
 140     public static <T> T create( Class<T> clazz ) {
 141         try {
 142             return create0(clazz);
 143         } catch (InstantiationException e) {
 144             logger.log(Level.INFO,"failed to create a new instance of "+clazz,e);
 145             throw new InstantiationError(e.toString());
 146         } catch (IllegalAccessException e) {
 147             logger.log(Level.INFO,"failed to create a new instance of "+clazz,e);
 148             throw new IllegalAccessError(e.toString());
 149         } catch (InvocationTargetException e) {
 150             Throwable target = e.getTargetException();
 151 
 152             // most likely an error on the user's code.
 153             // just let it through for the ease of debugging
 154             if(target instanceof RuntimeException)
 155                 throw (RuntimeException)target;
 156 
 157             // error. just forward it for the ease of debugging
 158             if(target instanceof Error)
 159                 throw (Error)target;
 160 
 161             // a checked exception.
 162             // not sure how we should report this error,
 163             // but for now we just forward it by wrapping it into a runtime exception
 164             throw new IllegalStateException(target);
 165         }
 166     }
 167 
 168     /**
 169      *  Call a method in the factory class to get the object.
 170      */
 171     public static Object create(Method method) {
 172         Throwable errorMsg;
 173         try {
 174             return method.invoke(null, emptyObject);
 175         } catch (InvocationTargetException ive) {
 176             Throwable target = ive.getTargetException();
 177 
 178             if(target instanceof RuntimeException)
 179                 throw (RuntimeException)target;
 180 
 181             if(target instanceof Error)
 182                 throw (Error)target;
 183 
 184             throw new IllegalStateException(target);
 185         } catch (IllegalAccessException e) {
 186             logger.log(Level.INFO,"failed to create a new instance of "+method.getReturnType().getName(),e);
 187             throw new IllegalAccessError(e.toString());
 188         } catch (IllegalArgumentException iae){
 189             logger.log(Level.INFO,"failed to create a new instance of "+method.getReturnType().getName(),iae);
 190             errorMsg = iae;
 191         } catch (NullPointerException npe){
 192             logger.log(Level.INFO,"failed to create a new instance of "+method.getReturnType().getName(),npe);
 193             errorMsg = npe;
 194         } catch (ExceptionInInitializerError eie){
 195             logger.log(Level.INFO,"failed to create a new instance of "+method.getReturnType().getName(),eie);
 196             errorMsg = eie;
 197         }
 198 
 199         NoSuchMethodError exp;
 200         exp = new NoSuchMethodError(errorMsg.getMessage());
 201         exp.initCause(errorMsg);
 202         throw exp;
 203     }
 204 
 205     /**
 206      * Infers the instanciable implementation class that can be assigned to the given field type.
 207      *
 208      * @return null
 209      *      if inference fails.
 210      */
 211     public static <T> Class<? extends T> inferImplClass(Class<T> fieldType, Class[] knownImplClasses) {
 212         if(!fieldType.isInterface())
 213             return fieldType;
 214 
 215         for( Class<?> impl : knownImplClasses ) {
 216             if(fieldType.isAssignableFrom(impl))
 217                 return impl.asSubclass(fieldType);
 218         }
 219 
 220         // if we can't find an implementation class,
 221         // let's just hope that we will never need to create a new object,
 222         // and returns null
 223         return null;
 224     }
 225 }