1 /*
   2  * Copyright (c) 2012, 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 java.lang.invoke;
  27 
  28 import java.security.*;
  29 import java.lang.reflect.*;
  30 import java.lang.invoke.MethodHandleNatives.Constants;
  31 import java.lang.invoke.MethodHandles.Lookup;
  32 import static java.lang.invoke.MethodHandleStatics.*;
  33 
  34 /*
  35  * Auxiliary to MethodHandleInfo, wants to nest in MethodHandleInfo but must be non-public.
  36  */
  37 /*non-public*/
  38 final
  39 class InfoFromMemberName implements MethodHandleInfo {
  40     private final MemberName member;
  41     private final int referenceKind;
  42 
  43     InfoFromMemberName(Lookup lookup, MemberName member, byte referenceKind) {
  44         assert(member.isResolved() || member.isMethodHandleInvoke());
  45         assert(member.referenceKindIsConsistentWith(referenceKind));
  46         this.member = member;
  47         this.referenceKind = referenceKind;
  48     }
  49 
  50     @Override
  51     public Class<?> getDeclaringClass() {
  52         return member.getDeclaringClass();
  53     }
  54 
  55     @Override
  56     public String getName() {
  57         return member.getName();
  58     }
  59 
  60     @Override
  61     public MethodType getMethodType() {
  62         return member.getMethodOrFieldType();
  63     }
  64 
  65     @Override
  66     public int getModifiers() {
  67         return member.getModifiers();
  68     }
  69 
  70     @Override
  71     public int getReferenceKind() {
  72         return referenceKind;
  73     }
  74 
  75     @Override
  76     public String toString() {
  77         return MethodHandleInfo.toString(getReferenceKind(), getDeclaringClass(), getName(), getMethodType());
  78     }
  79 
  80     @Override
  81     public <T extends Member> T reflectAs(Class<T> expected, Lookup lookup) {
  82         if (member.isMethodHandleInvoke() && !member.isVarargs()) {
  83             // This member is an instance of a signature-polymorphic method, which cannot be reflected
  84             // A method handle invoker can come in either of two forms:
  85             // A generic placeholder (present in the source code, and varargs)
  86             // and a signature-polymorphic instance (synthetic and not varargs).
  87             // For more information see comments on {@link MethodHandleNatives#linkMethod}.
  88             throw new IllegalArgumentException("cannot reflect signature polymorphic method");
  89         }
  90         Member mem = AccessController.doPrivileged(new PrivilegedAction<Member>() {
  91                 public Member run() {
  92                     try {
  93                         return reflectUnchecked();
  94                     } catch (ReflectiveOperationException ex) {
  95                         throw new IllegalArgumentException(ex);
  96                     }
  97                 }
  98             });
  99         try {
 100             Class<?> defc = getDeclaringClass();
 101             byte refKind = (byte) getReferenceKind();
 102             lookup.checkAccess(refKind, defc, convertToMemberName(refKind, mem));
 103         } catch (IllegalAccessException ex) {
 104             throw new IllegalArgumentException(ex);
 105         }
 106         return expected.cast(mem);
 107     }
 108 
 109     private Member reflectUnchecked() throws ReflectiveOperationException {
 110         byte refKind = (byte) getReferenceKind();
 111         Class<?> defc = getDeclaringClass();
 112         boolean isPublic = Modifier.isPublic(getModifiers());
 113         if (MethodHandleNatives.refKindIsMethod(refKind)) {
 114             if (isPublic)
 115                 return defc.getMethod(getName(), getMethodType().parameterArray());
 116             else
 117                 return defc.getDeclaredMethod(getName(), getMethodType().parameterArray());
 118         } else if (MethodHandleNatives.refKindIsConstructor(refKind)) {
 119             if (isPublic)
 120                 return defc.getConstructor(getMethodType().parameterArray());
 121             else
 122                 return defc.getDeclaredConstructor(getMethodType().parameterArray());
 123         } else if (MethodHandleNatives.refKindIsField(refKind)) {
 124             if (isPublic)
 125                 return defc.getField(getName());
 126             else
 127                 return defc.getDeclaredField(getName());
 128         } else {
 129             throw new IllegalArgumentException("referenceKind="+refKind);
 130         }
 131     }
 132 
 133     private static MemberName convertToMemberName(byte refKind, Member mem) throws IllegalAccessException {
 134         if (mem instanceof Method) {
 135             boolean wantSpecial = (refKind == REF_invokeSpecial);
 136             return MemberName.make((Method) mem, wantSpecial);
 137         } else if (mem instanceof Constructor) {
 138             return MemberName.make((Constructor) mem);
 139         } else if (mem instanceof Field) {
 140             boolean isSetter = (refKind == REF_putField || refKind == REF_putStatic);
 141             return MemberName.make((Field) mem, isSetter);
 142         }
 143         throw new InternalError(mem.getClass().getName());
 144     }
 145 }