1 /*
   2  * Copyright (c) 2018, 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 package java.lang.constant;
  26 
  27 import java.lang.invoke.MethodHandle;
  28 import java.lang.invoke.MethodHandles;
  29 import java.lang.invoke.MethodType;
  30 import java.util.Optional;
  31 
  32 import static java.lang.constant.ConstantDescs.BSM_INVOKE;
  33 import static java.lang.constant.ConstantDescs.CR_MethodHandle;
  34 import static java.util.Objects.requireNonNull;
  35 
  36 /**
  37  * A <a href="package-summary.html#nominal">nominal descriptor</a> for a
  38  * {@link MethodHandle} constant that performs a {@link MethodHandle#asType(MethodType)}
  39  * adaptation on another {@link MethodHandle}.
  40  */
  41 final class AsTypeMethodHandleDesc extends DynamicConstantDesc<MethodHandle>
  42         implements MethodHandleDesc {
  43 
  44     private final MethodHandleDesc underlying;
  45     private final MethodTypeDesc type;
  46 
  47     AsTypeMethodHandleDesc(MethodHandleDesc underlying, MethodTypeDesc type) {
  48         super(BSM_INVOKE, ConstantDescs.DEFAULT_NAME, CR_MethodHandle,
  49               ConstantDescs.MHR_METHODHANDLE_ASTYPE, underlying, type);
  50         this.underlying = requireNonNull(underlying);
  51         this.type = requireNonNull(type);
  52     }
  53 
  54     @Override
  55     public MethodTypeDesc methodType() {
  56         return type;
  57     }
  58 
  59     @Override
  60     public MethodHandle resolveConstantDesc(MethodHandles.Lookup lookup)
  61             throws ReflectiveOperationException {
  62         MethodHandle handle = underlying.resolveConstantDesc(lookup);
  63         MethodType methodType = type.resolveConstantDesc(lookup);
  64         return handle.asType(methodType);
  65     }
  66 
  67     @Override
  68     public Optional<? extends ConstantDesc<ConstantDesc<MethodHandle>>> describeConstable() {
  69         return ConstantUtils.symbolizeHelper(ConstantDescs.MHR_METHODHANDLEDESC_ASTYPE, ConstantDescs.CR_MethodHandleDesc,
  70                                              underlying, type);
  71     }
  72 
  73     @Override
  74     public String toString() {
  75         return  String.format("%s.asType%s", underlying.toString(), type.displayDescriptor());
  76     }
  77 }