1 /*
   2  * Copyright (c) 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.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  */
  23 
  24 package java.lang.invoke;
  25 
  26 import java.util.ArrayList;
  27 import java.util.Arrays;
  28 import java.util.List;
  29 
  30 import static java.lang.invoke.MethodHandleNatives.Constants.*;
  31 
  32 /**
  33  * Helper class, injected into java.lang.invoke,
  34  * that bridges to the private ClassSpecializer mechanism.
  35  */
  36 
  37 public interface ClassSpecializerHelper {
  38     interface Frob {
  39         Kind kind();
  40         int label();
  41         List<Object> asList();
  42     }
  43     abstract class FrobImpl implements Frob {
  44         private final int label;
  45         public FrobImpl(int label) {
  46             this.label = label;
  47         }
  48         public int label() { return label; }
  49         @Override public abstract Kind kind();
  50 
  51         public String toString() {
  52             final StringBuilder buf = new StringBuilder();
  53             buf.append("Frob[label=").append(label);
  54             final Kind k = kind();
  55             if (k != null) {
  56                 for (MethodHandle mh : k.getters()) {
  57                     Object x = "?";
  58                     try {
  59                         x = mh.invoke(this);
  60                     } catch (Throwable ex) {
  61                         x = "<<"+ex.getMessage()+">>";
  62                     }
  63                     buf.append(", ").append(x);
  64                 }
  65             }
  66             buf.append("]");
  67             return buf.toString();
  68         }
  69 
  70         public List<Object> asList() {
  71             final List<MethodHandle> getters = kind().getters();
  72             ArrayList<Object> res = new ArrayList<>(getters.size());
  73             for (MethodHandle getter : getters) {
  74                 try {
  75                     res.add(getter.invoke(this));
  76                 } catch (Throwable ex) {
  77                     throw new AssertionError(ex);
  78                 }
  79             }
  80             return res;
  81         }
  82     }
  83 
  84     public static class Kind extends ClassSpecializer<Frob, Byte, Kind>.SpeciesData {
  85         public Kind(SpecTest outer, Byte key) {
  86             outer.super(key);
  87         }
  88 
  89         public MethodHandle factory() {
  90             return super.factory();
  91         }
  92 
  93         public List<MethodHandle> getters() {
  94             return super.getters();
  95         }
  96 
  97         private static final List<Class<?>> FIELD_TYPES
  98                 = Arrays.asList(String.class, float.class, Double.class, boolean.class, Object[].class, Object.class);
  99 
 100         public static int MAX_KEY = FIELD_TYPES.size();
 101 
 102         @Override
 103         protected List<Class<?>> deriveFieldTypes(Byte key) {
 104             return FIELD_TYPES.subList(0, key);
 105         }
 106 
 107         @Override
 108         protected Class<? extends Frob> deriveSuperClass() {
 109             return FrobImpl.class;
 110         }
 111 
 112         @Override
 113         protected MethodHandle deriveTransformHelper(MemberName transform, int whichtm) {
 114             throw new AssertionError();
 115         }
 116 
 117         @Override
 118         protected <X> List<X> deriveTransformHelperArguments(MemberName transform, int whichtm, List<X> args, List<X> fields) {
 119             throw new AssertionError();
 120         }
 121     }
 122 
 123     class SpecTest extends ClassSpecializer<Frob, Byte, Kind> {
 124         private static final MemberName SPECIES_DATA_ACCESSOR;
 125         static {
 126             try {
 127                 SPECIES_DATA_ACCESSOR = MethodHandles.publicLookup()
 128                     .resolveOrFail(REF_invokeVirtual, FrobImpl.class, "kind", MethodType.methodType(Kind.class));
 129             } catch (ReflectiveOperationException ex) {
 130                 throw new AssertionError("Bootstrap link error", ex);
 131             }
 132         }
 133 
 134         public SpecTest() {
 135             super(Frob.class, Byte.class, Kind.class,
 136                     MethodType.methodType(void.class, int.class),
 137                     SPECIES_DATA_ACCESSOR,
 138                     "KIND",
 139                     Arrays.asList());
 140         }
 141 
 142         @Override
 143         protected Kind newSpeciesData(Byte key) {
 144             return new Kind(this, key);
 145         }
 146 
 147         public static Kind kind(int key) {
 148             return (Kind) SPEC_TEST.findSpecies((byte)key);
 149         }
 150     }
 151 
 152     static final SpecTest SPEC_TEST = new SpecTest();
 153 
 154 }
 155