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/*
 * Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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package java.lang.constant;

import java.lang.invoke.MethodHandle;
import java.lang.invoke.MethodHandleInfo;
import java.util.OptionalInt;
import java.util.stream.Stream;

import jdk.internal.vm.annotation.Stable;

import static java.lang.invoke.MethodHandleInfo.REF_getField;
import static java.lang.invoke.MethodHandleInfo.REF_getStatic;
import static java.lang.invoke.MethodHandleInfo.REF_invokeInterface;
import static java.lang.invoke.MethodHandleInfo.REF_invokeSpecial;
import static java.lang.invoke.MethodHandleInfo.REF_invokeStatic;
import static java.lang.invoke.MethodHandleInfo.REF_invokeVirtual;
import static java.lang.invoke.MethodHandleInfo.REF_newInvokeSpecial;
import static java.lang.invoke.MethodHandleInfo.REF_putField;
import static java.lang.invoke.MethodHandleInfo.REF_putStatic;

/**
 * A nominal descriptor for a direct
 * {@link MethodHandle}.  A {@linkplain DirectMethodHandleDesc} corresponds to
 * a {@code Constant_MethodHandle_info} entry in the constant pool of a classfile.
 *
 * @since 12
 */
public sealed interface DirectMethodHandleDesc
        extends MethodHandleDesc
        permits DirectMethodHandleDescImpl {
    /**
     * Kinds of method handles that can be described with {@linkplain DirectMethodHandleDesc}.
     *
     * @since 12
     */
    enum Kind {
        /** A method handle for a method invoked as with {@code invokestatic} */
        STATIC(REF_invokeStatic),
        /** A method handle for a method invoked as with {@code invokestatic} */
        INTERFACE_STATIC(REF_invokeStatic, true),
        /** A method handle for a method invoked as with {@code invokevirtual} */
        VIRTUAL(REF_invokeVirtual),
        /** A method handle for a method invoked as with {@code invokeinterface} */
        INTERFACE_VIRTUAL(REF_invokeInterface, true),
        /** A method handle for a method invoked as with {@code invokespecial} */
        SPECIAL(REF_invokeSpecial),
        /** A method handle for an interface method invoked as with {@code invokespecial} */
        INTERFACE_SPECIAL(REF_invokeSpecial, true),
        /** A method handle for a constructor */
        CONSTRUCTOR(REF_newInvokeSpecial),
        /** A method handle for a read accessor for an instance field  */
        GETTER(REF_getField),
        /** A method handle for a write accessor for an instance field  */
        SETTER(REF_putField),
        /** A method handle for a read accessor for a static field  */
        STATIC_GETTER(REF_getStatic),
        /** A method handle for a write accessor for a static field  */
        STATIC_SETTER(REF_putStatic);

        /** The corresponding {@code refKind} value for this kind of method handle,
         * as defined by {@link MethodHandleInfo}
         */
        public final int refKind;

        /** Is this an interface
         */
        public final boolean isInterface;
        Kind(int refKind) {
            this(refKind, false);
        }

        Kind(int refKind, boolean isInterface) { this.refKind = refKind; this.isInterface = isInterface; }

        /**
         * Returns the enumeration member with the given {@code refKind} field.
         * Behaves as if {@code valueOf(refKind, false)}.  As a special case,
         * if {@code refKind} is {@code REF_invokeInterface} (9) then the
         * {@code isInterface} field will be true.
         *
         * @param refKind refKind of desired member
         * @return the matching enumeration member
         * @throws IllegalArgumentException if there is no such member
         */
        public static Kind valueOf(int refKind) {
            return valueOf(refKind, refKind == REF_invokeInterface);
        }

        /**
         * Returns the enumeration member with the given the {@code refKind} and
         * {@code isInterface} arguments.
         * For most values of {@code refKind} there is an exact match regardless of the value of {@code isInterface}.
         * These are:
         * 
    *
  • {@code REF_invokeVirtual} which matches to {@code VIRTUAL} *
  • {@code REF_invokeInterface} which matches to {@code INTERFACE_VIRTUAL} *
  • {@code REF_newInvokeSpecial} which matches to {@code CONSTRUCTOR} *
  • {@code REF_getField} which matches to {@code GETTER} *
  • {@code REF_putField} which matches to {@code SETTER} *
  • {@code REF_getStatic} which matches to {@code STATIC_GETTER} *
  • {@code REF_putStatic} which matches to {@code STATIC_SETTER} *
* As for the rest, the returned kind will depend on the value (false or true accordingly) of {@code isInterface}: *
    *
  • {@code REF_invokeStatic} which matches to {@code STATIC} or {@code INTERFACE_STATIC} *
  • {@code REF_invokeSpecial} which matches to {@code SPECIAL} or {@code INTERFACE_SPECIAL} *
* @param refKind refKind of desired member * @param isInterface whether desired member is for interface methods * @return the matching enumeration member * @throws IllegalArgumentException if there is no such member */ public static Kind valueOf(int refKind, boolean isInterface) { int i = tableIndex(refKind, isInterface); if (i >= 2 && i < TABLE.length) { return TABLE[i]; } throw new IllegalArgumentException(String.format("refKind=%d isInterface=%s", refKind, isInterface)); } private static int tableIndex(int refKind, boolean isInterface) { if (refKind < 0) return refKind; return (refKind * 2) + (isInterface ? 1 : 0); } private static final @Stable Kind[] TABLE; static { // Pack the static table. int max = 0; for (Kind k : values()) max = Math.max(max, tableIndex(k.refKind, true)); TABLE = new Kind[max+1]; for (Kind kind : values()) { int i = tableIndex(kind.refKind, kind.isInterface); if (i >= TABLE.length || TABLE[i] != null) throw new AssertionError("TABLE entry for " + kind); TABLE[i] = kind; } // Pack in some aliases also. int ii = tableIndex(REF_invokeInterface, false); if (TABLE[ii] != null) throw new AssertionError("TABLE entry for (invokeInterface, false) used by " + TABLE[ii]); TABLE[ii] = INTERFACE_VIRTUAL; for (Kind kind : values()) { if (!kind.isInterface) { // Add extra cache entry to alias the isInterface case. // For example, (REF_getStatic, X) will produce STATIC_GETTER // for either truth value of X. int i = tableIndex(kind.refKind, true); if (TABLE[i] == null) { TABLE[i] = kind; } } } } /** * Does this {@code Kind} correspond to a virtual method invocation? * * @return if this {@code Kind} corresponds to a virtual method invocation */ boolean isVirtualMethod() { switch (this) { case VIRTUAL: case SPECIAL: case INTERFACE_VIRTUAL: case INTERFACE_SPECIAL: return true; default: return false; } } } /** * Returns the {@code kind} of the method handle described by this nominal * descriptor. * * @return the {@link Kind} */ Kind kind(); /** * Returns the {@code refKind} of the method handle described by this nominal * reference, as defined by {@link MethodHandleInfo}. * * @return the reference kind */ int refKind(); /** * Indicates if the method is declared by an interface * * @return true if the method is declared by an interface */ boolean isOwnerInterface(); /** * Returns a {@link ClassDesc} describing the class declaring the * method or field described by this nominal descriptor. * * @return the class declaring the method or field */ ClassDesc owner(); /** * Returns the name of the method or field described by this nominal descriptor. * For constructors, returns the reserved name {@code ""}. * * @return the name of the method or field */ String methodName(); /** * Returns the lookup descriptor of the method handle described by this descriptor, * after adjusting for the invocation mode. This will correspond to either * a method type descriptor string (for methods and constructors), or a field * descriptor string (for field access method handles). The lookup descriptor * string is in the same format as accepted by {@link MethodHandleDesc#of(Kind, ClassDesc, String, String)}. * * @return the lookup descriptor string */ String lookupDescriptor(); }




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