1 /*
   2  * Copyright (c) 2008, 2012, 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 sun.invoke.util.BytecodeDescriptor;
  29 import sun.invoke.util.VerifyAccess;
  30 
  31 import java.lang.reflect.Constructor;
  32 import java.lang.reflect.Field;
  33 import java.lang.reflect.Method;
  34 import java.lang.reflect.Member;
  35 import java.lang.reflect.Modifier;
  36 import java.util.ArrayList;
  37 import java.util.Arrays;
  38 import java.util.Collections;
  39 import java.util.Iterator;
  40 import java.util.List;
  41 import static java.lang.invoke.MethodHandleNatives.Constants.*;
  42 import static java.lang.invoke.MethodHandleStatics.*;
  43 import java.util.Objects;
  44 
  45 /**
  46  * A {@code MemberName} is a compact symbolic datum which fully characterizes
  47  * a method or field reference.
  48  * A member name refers to a field, method, constructor, or member type.
  49  * Every member name has a simple name (a string) and a type (either a Class or MethodType).
  50  * A member name may also have a non-null declaring class, or it may be simply
  51  * a naked name/type pair.
  52  * A member name may also have non-zero modifier flags.
  53  * Finally, a member name may be either resolved or unresolved.
  54  * If it is resolved, the existence of the named
  55  * <p>
  56  * Whether resolved or not, a member name provides no access rights or
  57  * invocation capability to its possessor.  It is merely a compact
  58  * representation of all symbolic information necessary to link to
  59  * and properly use the named member.
  60  * <p>
  61  * When resolved, a member name's internal implementation may include references to JVM metadata.
  62  * This representation is stateless and only decriptive.
  63  * It provides no private information and no capability to use the member.
  64  * <p>
  65  * By contrast, a {@linkplain java.lang.reflect.Method} contains fuller information
  66  * about the internals of a method (except its bytecodes) and also
  67  * allows invocation.  A MemberName is much lighter than a Method,
  68  * since it contains about 7 fields to the 16 of Method (plus its sub-arrays),
  69  * and those seven fields omit much of the information in Method.
  70  * @author jrose
  71  */
  72 /*non-public*/ final class MemberName implements Member, Cloneable {
  73     private Class<?>   clazz;       // class in which the method is defined
  74     private String     name;        // may be null if not yet materialized
  75     private Object     type;        // may be null if not yet materialized
  76     private int        flags;       // modifier bits; see reflect.Modifier
  77     //@Injected JVM_Method* vmtarget;
  78     //@Injected int         vmindex;
  79     private Object     resolution;  // if null, this guy is resolved
  80 
  81     /** Return the declaring class of this member.
  82      *  In the case of a bare name and type, the declaring class will be null.
  83      */
  84     public Class<?> getDeclaringClass() {
  85         return clazz;
  86     }
  87 
  88     /** Utility method producing the class loader of the declaring class. */
  89     public ClassLoader getClassLoader() {
  90         return clazz.getClassLoader();
  91     }
  92 
  93     /** Return the simple name of this member.
  94      *  For a type, it is the same as {@link Class#getSimpleName}.
  95      *  For a method or field, it is the simple name of the member.
  96      *  For a constructor, it is always {@code "&lt;init&gt;"}.
  97      */
  98     public String getName() {
  99         if (name == null) {
 100             expandFromVM();
 101             if (name == null)  return null;
 102         }
 103         return name;
 104     }
 105 
 106     public MethodType getMethodOrFieldType() {
 107         if (isInvocable())
 108             return getMethodType();
 109         if (isGetter())
 110             return MethodType.methodType(getFieldType());
 111         if (isSetter())
 112             return MethodType.methodType(void.class, getFieldType());
 113         throw new InternalError("not a method or field: "+this);
 114     }
 115 
 116     /** Return the declared type of this member, which
 117      *  must be a method or constructor.
 118      */
 119     public MethodType getMethodType() {
 120         if (type == null) {
 121             expandFromVM();
 122             if (type == null)  return null;
 123         }
 124         if (!isInvocable())
 125             throw newIllegalArgumentException("not invocable, no method type");
 126         if (type instanceof MethodType) {
 127             return (MethodType) type;
 128         }
 129         if (type instanceof String) {
 130             String sig = (String) type;
 131             MethodType res = MethodType.fromMethodDescriptorString(sig, getClassLoader());
 132             this.type = res;
 133             return res;
 134         }
 135         if (type instanceof Object[]) {
 136             Object[] typeInfo = (Object[]) type;
 137             Class<?>[] ptypes = (Class<?>[]) typeInfo[1];
 138             Class<?> rtype = (Class<?>) typeInfo[0];
 139             MethodType res = MethodType.methodType(rtype, ptypes);
 140             this.type = res;
 141             return res;
 142         }
 143         throw new InternalError("bad method type "+type);
 144     }
 145 
 146     /** Return the actual type under which this method or constructor must be invoked.
 147      *  For non-static methods or constructors, this is the type with a leading parameter,
 148      *  a reference to declaring class.  For static methods, it is the same as the declared type.
 149      */
 150     public MethodType getInvocationType() {
 151         MethodType itype = getMethodOrFieldType();
 152         if (isConstructor() && getReferenceKind() == REF_newInvokeSpecial)
 153             return itype.changeReturnType(clazz);
 154         if (!isStatic())
 155             return itype.insertParameterTypes(0, clazz);
 156         return itype;
 157     }
 158 
 159     /** Utility method producing the parameter types of the method type. */
 160     public Class<?>[] getParameterTypes() {
 161         return getMethodType().parameterArray();
 162     }
 163 
 164     /** Utility method producing the return type of the method type. */
 165     public Class<?> getReturnType() {
 166         return getMethodType().returnType();
 167     }
 168 
 169     /** Return the declared type of this member, which
 170      *  must be a field or type.
 171      *  If it is a type member, that type itself is returned.
 172      */
 173     public Class<?> getFieldType() {
 174         if (type == null) {
 175             expandFromVM();
 176             if (type == null)  return null;
 177         }
 178         if (isInvocable())
 179             throw newIllegalArgumentException("not a field or nested class, no simple type");
 180         if (type instanceof Class<?>) {
 181             return (Class<?>) type;
 182         }
 183         if (type instanceof String) {
 184             String sig = (String) type;
 185             MethodType mtype = MethodType.fromMethodDescriptorString("()"+sig, getClassLoader());
 186             Class<?> res = mtype.returnType();
 187             this.type = res;
 188             return res;
 189         }
 190         throw new InternalError("bad field type "+type);
 191     }
 192 
 193     /** Utility method to produce either the method type or field type of this member. */
 194     public Object getType() {
 195         return (isInvocable() ? getMethodType() : getFieldType());
 196     }
 197 
 198     /** Utility method to produce the signature of this member,
 199      *  used within the class file format to describe its type.
 200      */
 201     public String getSignature() {
 202         if (type == null) {
 203             expandFromVM();
 204             if (type == null)  return null;
 205         }
 206         if (type instanceof String)
 207             return (String) type;
 208         if (isInvocable())
 209             return BytecodeDescriptor.unparse(getMethodType());
 210         else
 211             return BytecodeDescriptor.unparse(getFieldType());
 212     }
 213 
 214     /** Return the modifier flags of this member.
 215      *  @see java.lang.reflect.Modifier
 216      */
 217     public int getModifiers() {
 218         return (flags & RECOGNIZED_MODIFIERS);
 219     }
 220 
 221     /** Return the reference kind of this member, or zero if none.
 222      */
 223     public byte getReferenceKind() {
 224         return (byte) ((flags >>> MN_REFERENCE_KIND_SHIFT) & MN_REFERENCE_KIND_MASK);
 225     }
 226     private boolean referenceKindIsConsistent() {
 227         byte refKind = getReferenceKind();
 228         if (refKind == REF_NONE)  return isType();
 229         if (isField()) {
 230             assert(staticIsConsistent());
 231             assert(MethodHandleNatives.refKindIsField(refKind));
 232         } else if (isConstructor()) {
 233             assert(refKind == REF_newInvokeSpecial || refKind == REF_invokeSpecial);
 234         } else if (isMethod()) {
 235             assert(staticIsConsistent());
 236             assert(MethodHandleNatives.refKindIsMethod(refKind));
 237             if (clazz.isInterface())
 238                 assert(refKind == REF_invokeInterface ||
 239                        refKind == REF_invokeStatic    ||
 240                        refKind == REF_invokeSpecial   ||
 241                        refKind == REF_invokeVirtual && isObjectPublicMethod());
 242         } else {
 243             assert(false);
 244         }
 245         return true;
 246     }
 247     private boolean isObjectPublicMethod() {
 248         if (clazz == Object.class)  return true;
 249         MethodType mtype = getMethodType();
 250         if (name.equals("toString") && mtype.returnType() == String.class && mtype.parameterCount() == 0)
 251             return true;
 252         if (name.equals("hashCode") && mtype.returnType() == int.class && mtype.parameterCount() == 0)
 253             return true;
 254         if (name.equals("equals") && mtype.returnType() == boolean.class && mtype.parameterCount() == 1 && mtype.parameterType(0) == Object.class)
 255             return true;
 256         return false;
 257     }
 258     /*non-public*/ boolean referenceKindIsConsistentWith(int originalRefKind) {
 259         int refKind = getReferenceKind();
 260         if (refKind == originalRefKind)  return true;
 261         switch (originalRefKind) {
 262         case REF_invokeInterface:
 263             // Looking up an interface method, can get (e.g.) Object.hashCode
 264             assert(refKind == REF_invokeVirtual ||
 265                    refKind == REF_invokeSpecial) : this;
 266             return true;
 267         case REF_invokeVirtual:
 268         case REF_newInvokeSpecial:
 269             // Looked up a virtual, can get (e.g.) final String.hashCode.
 270             assert(refKind == REF_invokeSpecial) : this;
 271             return true;
 272         }
 273         assert(false) : this+" != "+MethodHandleNatives.refKindName((byte)originalRefKind);
 274         return true;
 275     }
 276     private boolean staticIsConsistent() {
 277         byte refKind = getReferenceKind();
 278         return MethodHandleNatives.refKindIsStatic(refKind) == isStatic() || getModifiers() == 0;
 279     }
 280     private boolean vminfoIsConsistent() {
 281         byte refKind = getReferenceKind();
 282         assert(isResolved());  // else don't call
 283         Object vminfo = MethodHandleNatives.getMemberVMInfo(this);
 284         assert(vminfo instanceof Object[]);
 285         long vmindex = (Long) ((Object[])vminfo)[0];
 286         Object vmtarget = ((Object[])vminfo)[1];
 287         if (MethodHandleNatives.refKindIsField(refKind)) {
 288             assert(vmindex >= 0) : vmindex + ":" + this;
 289             assert(vmtarget instanceof Class);
 290         } else {
 291             if (MethodHandleNatives.refKindDoesDispatch(refKind))
 292                 assert(vmindex >= 0) : vmindex + ":" + this;
 293             else
 294                 assert(vmindex < 0) : vmindex;
 295             assert(vmtarget instanceof MemberName) : vmtarget + " in " + this;
 296         }
 297         return true;
 298     }
 299 
 300     private MemberName changeReferenceKind(byte refKind, byte oldKind) {
 301         assert(getReferenceKind() == oldKind);
 302         assert(MethodHandleNatives.refKindIsValid(refKind));
 303         flags += (((int)refKind - oldKind) << MN_REFERENCE_KIND_SHIFT);
 304 //        if (isConstructor() && refKind != REF_newInvokeSpecial)
 305 //            flags += (IS_METHOD - IS_CONSTRUCTOR);
 306 //        else if (refKind == REF_newInvokeSpecial && isMethod())
 307 //            flags += (IS_CONSTRUCTOR - IS_METHOD);
 308         return this;
 309     }
 310 
 311     private boolean testFlags(int mask, int value) {
 312         return (flags & mask) == value;
 313     }
 314     private boolean testAllFlags(int mask) {
 315         return testFlags(mask, mask);
 316     }
 317     private boolean testAnyFlags(int mask) {
 318         return !testFlags(mask, 0);
 319     }
 320 
 321     /** Utility method to query if this member is a method handle invocation (invoke or invokeExact). */
 322     public boolean isMethodHandleInvoke() {
 323         final int bits = MH_INVOKE_MODS;
 324         final int negs = Modifier.STATIC;
 325         if (testFlags(bits | negs, bits) &&
 326             clazz == MethodHandle.class) {
 327             return isMethodHandleInvokeName(name);
 328         }
 329         return false;
 330     }
 331     public static boolean isMethodHandleInvokeName(String name) {
 332         return name.equals("invoke") || name.equals("invokeExact");
 333     }
 334     private static final int MH_INVOKE_MODS = Modifier.NATIVE | Modifier.FINAL | Modifier.PUBLIC;
 335 
 336     /** Utility method to query the modifier flags of this member. */
 337     public boolean isStatic() {
 338         return Modifier.isStatic(flags);
 339     }
 340     /** Utility method to query the modifier flags of this member. */
 341     public boolean isPublic() {
 342         return Modifier.isPublic(flags);
 343     }
 344     /** Utility method to query the modifier flags of this member. */
 345     public boolean isPrivate() {
 346         return Modifier.isPrivate(flags);
 347     }
 348     /** Utility method to query the modifier flags of this member. */
 349     public boolean isProtected() {
 350         return Modifier.isProtected(flags);
 351     }
 352     /** Utility method to query the modifier flags of this member. */
 353     public boolean isFinal() {
 354         return Modifier.isFinal(flags);
 355     }
 356     /** Utility method to query whether this member or its defining class is final. */
 357     public boolean canBeStaticallyBound() {
 358         return Modifier.isFinal(flags | clazz.getModifiers());
 359     }
 360     /** Utility method to query the modifier flags of this member. */
 361     public boolean isVolatile() {
 362         return Modifier.isVolatile(flags);
 363     }
 364     /** Utility method to query the modifier flags of this member. */
 365     public boolean isAbstract() {
 366         return Modifier.isAbstract(flags);
 367     }
 368     /** Utility method to query the modifier flags of this member. */
 369     public boolean isNative() {
 370         return Modifier.isNative(flags);
 371     }
 372     // let the rest (native, volatile, transient, etc.) be tested via Modifier.isFoo
 373 
 374     // unofficial modifier flags, used by HotSpot:
 375     static final int BRIDGE    = 0x00000040;
 376     static final int VARARGS   = 0x00000080;
 377     static final int SYNTHETIC = 0x00001000;
 378     static final int ANNOTATION= 0x00002000;
 379     static final int ENUM      = 0x00004000;
 380     /** Utility method to query the modifier flags of this member; returns false if the member is not a method. */
 381     public boolean isBridge() {
 382         return testAllFlags(IS_METHOD | BRIDGE);
 383     }
 384     /** Utility method to query the modifier flags of this member; returns false if the member is not a method. */
 385     public boolean isVarargs() {
 386         return testAllFlags(VARARGS) && isInvocable();
 387     }
 388     /** Utility method to query the modifier flags of this member; returns false if the member is not a method. */
 389     public boolean isSynthetic() {
 390         return testAllFlags(SYNTHETIC);
 391     }
 392 
 393     static final String CONSTRUCTOR_NAME = "<init>";  // the ever-popular
 394 
 395     // modifiers exported by the JVM:
 396     static final int RECOGNIZED_MODIFIERS = 0xFFFF;
 397 
 398     // private flags, not part of RECOGNIZED_MODIFIERS:
 399     static final int
 400             IS_METHOD        = MN_IS_METHOD,        // method (not constructor)
 401             IS_CONSTRUCTOR   = MN_IS_CONSTRUCTOR,   // constructor
 402             IS_FIELD         = MN_IS_FIELD,         // field
 403             IS_TYPE          = MN_IS_TYPE,          // nested type
 404             CALLER_SENSITIVE = MN_CALLER_SENSITIVE; // @CallerSensitive annotation detected
 405 
 406     static final int ALL_ACCESS = Modifier.PUBLIC | Modifier.PRIVATE | Modifier.PROTECTED;
 407     static final int ALL_KINDS = IS_METHOD | IS_CONSTRUCTOR | IS_FIELD | IS_TYPE;
 408     static final int IS_INVOCABLE = IS_METHOD | IS_CONSTRUCTOR;
 409     static final int IS_FIELD_OR_METHOD = IS_METHOD | IS_FIELD;
 410     static final int SEARCH_ALL_SUPERS = MN_SEARCH_SUPERCLASSES | MN_SEARCH_INTERFACES;
 411 
 412     /** Utility method to query whether this member is a method or constructor. */
 413     public boolean isInvocable() {
 414         return testAnyFlags(IS_INVOCABLE);
 415     }
 416     /** Utility method to query whether this member is a method, constructor, or field. */
 417     public boolean isFieldOrMethod() {
 418         return testAnyFlags(IS_FIELD_OR_METHOD);
 419     }
 420     /** Query whether this member is a method. */
 421     public boolean isMethod() {
 422         return testAllFlags(IS_METHOD);
 423     }
 424     /** Query whether this member is a constructor. */
 425     public boolean isConstructor() {
 426         return testAllFlags(IS_CONSTRUCTOR);
 427     }
 428     /** Query whether this member is a field. */
 429     public boolean isField() {
 430         return testAllFlags(IS_FIELD);
 431     }
 432     /** Query whether this member is a type. */
 433     public boolean isType() {
 434         return testAllFlags(IS_TYPE);
 435     }
 436     /** Utility method to query whether this member is neither public, private, nor protected. */
 437     public boolean isPackage() {
 438         return !testAnyFlags(ALL_ACCESS);
 439     }
 440     /** Query whether this member has a CallerSensitive annotation. */
 441     public boolean isCallerSensitive() {
 442         return testAllFlags(CALLER_SENSITIVE);
 443     }
 444 
 445     /** Utility method to query whether this member is accessible from a given lookup class. */
 446     public boolean isAccessibleFrom(Class<?> lookupClass) {
 447         return VerifyAccess.isMemberAccessible(this.getDeclaringClass(), this.getDeclaringClass(), flags,
 448                                                lookupClass, ALL_ACCESS|MethodHandles.Lookup.PACKAGE);
 449     }
 450 
 451     /** Initialize a query.   It is not resolved. */
 452     private void init(Class<?> defClass, String name, Object type, int flags) {
 453         // defining class is allowed to be null (for a naked name/type pair)
 454         //name.toString();  // null check
 455         //type.equals(type);  // null check
 456         // fill in fields:
 457         this.clazz = defClass;
 458         this.name = name;
 459         this.type = type;
 460         this.flags = flags;
 461         assert(testAnyFlags(ALL_KINDS));
 462         assert(this.resolution == null);  // nobody should have touched this yet
 463         //assert(referenceKindIsConsistent());  // do this after resolution
 464     }
 465 
 466     private void expandFromVM() {
 467         if (!isResolved())  return;
 468         if (type instanceof Object[])
 469             type = null;  // don't saddle JVM w/ typeInfo
 470         MethodHandleNatives.expand(this);
 471     }
 472 
 473     // Capturing information from the Core Reflection API:
 474     private static int flagsMods(int flags, int mods, byte refKind) {
 475         assert((flags & RECOGNIZED_MODIFIERS) == 0);
 476         assert((mods & ~RECOGNIZED_MODIFIERS) == 0);
 477         assert((refKind & ~MN_REFERENCE_KIND_MASK) == 0);
 478         return flags | mods | (refKind << MN_REFERENCE_KIND_SHIFT);
 479     }
 480     /** Create a name for the given reflected method.  The resulting name will be in a resolved state. */
 481     public MemberName(Method m) {
 482         this(m, false);
 483     }
 484     @SuppressWarnings("LeakingThisInConstructor")
 485     public MemberName(Method m, boolean wantSpecial) {
 486         m.getClass();  // NPE check
 487         // fill in vmtarget, vmindex while we have m in hand:
 488         MethodHandleNatives.init(this, m);
 489         if (clazz == null) {  // MHN.init failed
 490             if (m.getDeclaringClass() == MethodHandle.class &&
 491                 isMethodHandleInvokeName(m.getName())) {
 492                 // The JVM did not reify this signature-polymorphic instance.
 493                 // Need a special case here.
 494                 // See comments on MethodHandleNatives.linkMethod.
 495                 MethodType type = MethodType.methodType(m.getReturnType(), m.getParameterTypes());
 496                 int flags = flagsMods(IS_METHOD, m.getModifiers(), REF_invokeVirtual);
 497                 init(MethodHandle.class, m.getName(), type, flags);
 498                 if (isMethodHandleInvoke())
 499                     return;
 500             }
 501             throw new LinkageError(m.toString());
 502         }
 503         assert(isResolved() && this.clazz != null);
 504         this.name = m.getName();
 505         if (this.type == null)
 506             this.type = new Object[] { m.getReturnType(), m.getParameterTypes() };
 507         if (wantSpecial) {
 508             if (isAbstract())
 509                 throw new AbstractMethodError(this.toString());
 510             if (getReferenceKind() == REF_invokeVirtual)
 511                 changeReferenceKind(REF_invokeSpecial, REF_invokeVirtual);
 512             else if (getReferenceKind() == REF_invokeInterface)
 513                 // invokeSpecial on a default method
 514                 changeReferenceKind(REF_invokeSpecial, REF_invokeInterface);
 515         }
 516     }
 517     public MemberName asSpecial() {
 518         switch (getReferenceKind()) {
 519         case REF_invokeSpecial:     return this;
 520         case REF_invokeVirtual:     return clone().changeReferenceKind(REF_invokeSpecial, REF_invokeVirtual);
 521         case REF_invokeInterface:   return clone().changeReferenceKind(REF_invokeSpecial, REF_invokeInterface);
 522         case REF_newInvokeSpecial:  return clone().changeReferenceKind(REF_invokeSpecial, REF_newInvokeSpecial);
 523         }
 524         throw new IllegalArgumentException(this.toString());
 525     }
 526     public MemberName asConstructor() {
 527         switch (getReferenceKind()) {
 528         case REF_invokeSpecial:     return clone().changeReferenceKind(REF_newInvokeSpecial, REF_invokeSpecial);
 529         case REF_newInvokeSpecial:  return this;
 530         }
 531         throw new IllegalArgumentException(this.toString());
 532     }
 533     /** Create a name for the given reflected constructor.  The resulting name will be in a resolved state. */
 534     @SuppressWarnings("LeakingThisInConstructor")
 535     public MemberName(Constructor<?> ctor) {
 536         ctor.getClass();  // NPE check
 537         // fill in vmtarget, vmindex while we have ctor in hand:
 538         MethodHandleNatives.init(this, ctor);
 539         assert(isResolved() && this.clazz != null);
 540         this.name = CONSTRUCTOR_NAME;
 541         if (this.type == null)
 542             this.type = new Object[] { void.class, ctor.getParameterTypes() };
 543     }
 544     /** Create a name for the given reflected field.  The resulting name will be in a resolved state.
 545      */
 546     public MemberName(Field fld) {
 547         this(fld, false);
 548     }
 549     @SuppressWarnings("LeakingThisInConstructor")
 550     public MemberName(Field fld, boolean makeSetter) {
 551         fld.getClass();  // NPE check
 552         // fill in vmtarget, vmindex while we have fld in hand:
 553         MethodHandleNatives.init(this, fld);
 554         assert(isResolved() && this.clazz != null);
 555         this.name = fld.getName();
 556         this.type = fld.getType();
 557         assert((REF_putStatic - REF_getStatic) == (REF_putField - REF_getField));
 558         byte refKind = this.getReferenceKind();
 559         assert(refKind == (isStatic() ? REF_getStatic : REF_getField));
 560         if (makeSetter) {
 561             changeReferenceKind((byte)(refKind + (REF_putStatic - REF_getStatic)), refKind);
 562         }
 563     }
 564     public boolean isGetter() {
 565         return MethodHandleNatives.refKindIsGetter(getReferenceKind());
 566     }
 567     public boolean isSetter() {
 568         return MethodHandleNatives.refKindIsSetter(getReferenceKind());
 569     }
 570     public MemberName asSetter() {
 571         byte refKind = getReferenceKind();
 572         assert(MethodHandleNatives.refKindIsGetter(refKind));
 573         assert((REF_putStatic - REF_getStatic) == (REF_putField - REF_getField));
 574         byte setterRefKind = (byte)(refKind + (REF_putField - REF_getField));
 575         return clone().changeReferenceKind(setterRefKind, refKind);
 576     }
 577     /** Create a name for the given class.  The resulting name will be in a resolved state. */
 578     public MemberName(Class<?> type) {
 579         init(type.getDeclaringClass(), type.getSimpleName(), type,
 580                 flagsMods(IS_TYPE, type.getModifiers(), REF_NONE));
 581         initResolved(true);
 582     }
 583 
 584     /**
 585      * Create a name for a signature-polymorphic invoker.
 586      * This is a placeholder for a signature-polymorphic instance
 587      * (of MH.invokeExact, etc.) that the JVM does not reify.
 588      * See comments on {@link MethodHandleNatives#linkMethod}.
 589      */
 590     static MemberName makeMethodHandleInvoke(String name, MethodType type) {
 591         return makeMethodHandleInvoke(name, type, MH_INVOKE_MODS | SYNTHETIC);
 592     }
 593     static MemberName makeMethodHandleInvoke(String name, MethodType type, int mods) {
 594         MemberName mem = new MemberName(MethodHandle.class, name, type, REF_invokeVirtual);
 595         mem.flags |= mods;  // it's not resolved, but add these modifiers anyway
 596         assert(mem.isMethodHandleInvoke()) : mem;
 597         return mem;
 598     }
 599 
 600     // bare-bones constructor; the JVM will fill it in
 601     MemberName() { }
 602 
 603     // locally useful cloner
 604     @Override protected MemberName clone() {
 605         try {
 606             return (MemberName) super.clone();
 607         } catch (CloneNotSupportedException ex) {
 608             throw newInternalError(ex);
 609         }
 610      }
 611 
 612     /** Get the definition of this member name.
 613      *  This may be in a super-class of the declaring class of this member.
 614      */
 615     public MemberName getDefinition() {
 616         if (!isResolved())  throw new IllegalStateException("must be resolved: "+this);
 617         if (isType())  return this;
 618         MemberName res = this.clone();
 619         res.clazz = null;
 620         res.type = null;
 621         res.name = null;
 622         res.resolution = res;
 623         res.expandFromVM();
 624         assert(res.getName().equals(this.getName()));
 625         return res;
 626     }
 627 
 628     @Override
 629     public int hashCode() {
 630         return Objects.hash(clazz, flags, name, getType());
 631     }
 632     @Override
 633     public boolean equals(Object that) {
 634         return (that instanceof MemberName && this.equals((MemberName)that));
 635     }
 636 
 637     /** Decide if two member names have exactly the same symbolic content.
 638      *  Does not take into account any actual class members, so even if
 639      *  two member names resolve to the same actual member, they may
 640      *  be distinct references.
 641      */
 642     public boolean equals(MemberName that) {
 643         if (this == that)  return true;
 644         if (that == null)  return false;
 645         return this.clazz == that.clazz
 646                 && this.flags == that.flags
 647                 && Objects.equals(this.name, that.name)
 648                 && Objects.equals(this.getType(), that.getType());
 649     }
 650 
 651     // Construction from symbolic parts, for queries:
 652     /** Create a field or type name from the given components:  Declaring class, name, type, reference kind.
 653      *  The declaring class may be supplied as null if this is to be a bare name and type.
 654      *  The resulting name will in an unresolved state.
 655      */
 656     public MemberName(Class<?> defClass, String name, Class<?> type, byte refKind) {
 657         init(defClass, name, type, flagsMods(IS_FIELD, 0, refKind));
 658         initResolved(false);
 659     }
 660     /** Create a field or type name from the given components:  Declaring class, name, type.
 661      *  The declaring class may be supplied as null if this is to be a bare name and type.
 662      *  The modifier flags default to zero.
 663      *  The resulting name will in an unresolved state.
 664      */
 665     public MemberName(Class<?> defClass, String name, Class<?> type, Void unused) {
 666         this(defClass, name, type, REF_NONE);
 667         initResolved(false);
 668     }
 669     /** Create a method or constructor name from the given components:  Declaring class, name, type, modifiers.
 670      *  It will be a constructor if and only if the name is {@code "&lt;init&gt;"}.
 671      *  The declaring class may be supplied as null if this is to be a bare name and type.
 672      *  The last argument is optional, a boolean which requests REF_invokeSpecial.
 673      *  The resulting name will in an unresolved state.
 674      */
 675     public MemberName(Class<?> defClass, String name, MethodType type, byte refKind) {
 676         @SuppressWarnings("LocalVariableHidesMemberVariable")
 677         int flags = (name != null && name.equals(CONSTRUCTOR_NAME) ? IS_CONSTRUCTOR : IS_METHOD);
 678         init(defClass, name, type, flagsMods(flags, 0, refKind));
 679         initResolved(false);
 680     }
 681 //    /** Create a method or constructor name from the given components:  Declaring class, name, type, modifiers.
 682 //     *  It will be a constructor if and only if the name is {@code "&lt;init&gt;"}.
 683 //     *  The declaring class may be supplied as null if this is to be a bare name and type.
 684 //     *  The modifier flags default to zero.
 685 //     *  The resulting name will in an unresolved state.
 686 //     */
 687 //    public MemberName(Class<?> defClass, String name, MethodType type, Void unused) {
 688 //        this(defClass, name, type, REF_NONE);
 689 //    }
 690 
 691     /** Query whether this member name is resolved to a non-static, non-final method.
 692      */
 693     public boolean hasReceiverTypeDispatch() {
 694         return MethodHandleNatives.refKindDoesDispatch(getReferenceKind());
 695     }
 696 
 697     /** Query whether this member name is resolved.
 698      *  A resolved member name is one for which the JVM has found
 699      *  a method, constructor, field, or type binding corresponding exactly to the name.
 700      *  (Document?)
 701      */
 702     public boolean isResolved() {
 703         return resolution == null;
 704     }
 705 
 706     private void initResolved(boolean isResolved) {
 707         assert(this.resolution == null);  // not initialized yet!
 708         if (!isResolved)
 709             this.resolution = this;
 710         assert(isResolved() == isResolved);
 711     }
 712 
 713     void checkForTypeAlias() {
 714         if (isInvocable()) {
 715             MethodType type;
 716             if (this.type instanceof MethodType)
 717                 type = (MethodType) this.type;
 718             else
 719                 this.type = type = getMethodType();
 720             if (type.erase() == type)  return;
 721             if (VerifyAccess.isTypeVisible(type, clazz))  return;
 722             throw new LinkageError("bad method type alias: "+type+" not visible from "+clazz);
 723         } else {
 724             Class<?> type;
 725             if (this.type instanceof Class<?>)
 726                 type = (Class<?>) this.type;
 727             else
 728                 this.type = type = getFieldType();
 729             if (VerifyAccess.isTypeVisible(type, clazz))  return;
 730             throw new LinkageError("bad field type alias: "+type+" not visible from "+clazz);
 731         }
 732     }
 733 
 734 
 735     /** Produce a string form of this member name.
 736      *  For types, it is simply the type's own string (as reported by {@code toString}).
 737      *  For fields, it is {@code "DeclaringClass.name/type"}.
 738      *  For methods and constructors, it is {@code "DeclaringClass.name(ptype...)rtype"}.
 739      *  If the declaring class is null, the prefix {@code "DeclaringClass."} is omitted.
 740      *  If the member is unresolved, a prefix {@code "*."} is prepended.
 741      */
 742     @SuppressWarnings("LocalVariableHidesMemberVariable")
 743     @Override
 744     public String toString() {
 745         if (isType())
 746             return type.toString();  // class java.lang.String
 747         // else it is a field, method, or constructor
 748         StringBuilder buf = new StringBuilder();
 749         if (getDeclaringClass() != null) {
 750             buf.append(getName(clazz));
 751             buf.append('.');
 752         }
 753         String name = getName();
 754         buf.append(name == null ? "*" : name);
 755         Object type = getType();
 756         if (!isInvocable()) {
 757             buf.append('/');
 758             buf.append(type == null ? "*" : getName(type));
 759         } else {
 760             buf.append(type == null ? "(*)*" : getName(type));
 761         }
 762         byte refKind = getReferenceKind();
 763         if (refKind != REF_NONE) {
 764             buf.append('/');
 765             buf.append(MethodHandleNatives.refKindName(refKind));
 766         }
 767         //buf.append("#").append(System.identityHashCode(this));
 768         return buf.toString();
 769     }
 770     private static String getName(Object obj) {
 771         if (obj instanceof Class<?>)
 772             return ((Class<?>)obj).getName();
 773         return String.valueOf(obj);
 774     }
 775 
 776     public IllegalAccessException makeAccessException(String message, Object from) {
 777         message = message + ": "+ toString();
 778         if (from != null)  message += ", from " + from;
 779         return new IllegalAccessException(message);
 780     }
 781     private String message() {
 782         if (isResolved())
 783             return "no access";
 784         else if (isConstructor())
 785             return "no such constructor";
 786         else if (isMethod())
 787             return "no such method";
 788         else
 789             return "no such field";
 790     }
 791     public ReflectiveOperationException makeAccessException() {
 792         String message = message() + ": "+ toString();
 793         ReflectiveOperationException ex;
 794         if (isResolved() || !(resolution instanceof NoSuchMethodError ||
 795                               resolution instanceof NoSuchFieldError))
 796             ex = new IllegalAccessException(message);
 797         else if (isConstructor())
 798             ex = new NoSuchMethodException(message);
 799         else if (isMethod())
 800             ex = new NoSuchMethodException(message);
 801         else
 802             ex = new NoSuchFieldException(message);
 803         if (resolution instanceof Throwable)
 804             ex.initCause((Throwable) resolution);
 805         return ex;
 806     }
 807 
 808     /** Actually making a query requires an access check. */
 809     /*non-public*/ static Factory getFactory() {
 810         return Factory.INSTANCE;
 811     }
 812     /** A factory type for resolving member names with the help of the VM.
 813      *  TBD: Define access-safe public constructors for this factory.
 814      */
 815     /*non-public*/ static class Factory {
 816         private Factory() { } // singleton pattern
 817         static Factory INSTANCE = new Factory();
 818 
 819         private static int ALLOWED_FLAGS = ALL_KINDS;
 820 
 821         /// Queries
 822         List<MemberName> getMembers(Class<?> defc,
 823                 String matchName, Object matchType,
 824                 int matchFlags, Class<?> lookupClass) {
 825             matchFlags &= ALLOWED_FLAGS;
 826             String matchSig = null;
 827             if (matchType != null) {
 828                 matchSig = BytecodeDescriptor.unparse(matchType);
 829                 if (matchSig.startsWith("("))
 830                     matchFlags &= ~(ALL_KINDS & ~IS_INVOCABLE);
 831                 else
 832                     matchFlags &= ~(ALL_KINDS & ~IS_FIELD);
 833             }
 834             final int BUF_MAX = 0x2000;
 835             int len1 = matchName == null ? 10 : matchType == null ? 4 : 1;
 836             MemberName[] buf = newMemberBuffer(len1);
 837             int totalCount = 0;
 838             ArrayList<MemberName[]> bufs = null;
 839             int bufCount = 0;
 840             for (;;) {
 841                 bufCount = MethodHandleNatives.getMembers(defc,
 842                         matchName, matchSig, matchFlags,
 843                         lookupClass,
 844                         totalCount, buf);
 845                 if (bufCount <= buf.length) {
 846                     if (bufCount < 0)  bufCount = 0;
 847                     totalCount += bufCount;
 848                     break;
 849                 }
 850                 // JVM returned to us with an intentional overflow!
 851                 totalCount += buf.length;
 852                 int excess = bufCount - buf.length;
 853                 if (bufs == null)  bufs = new ArrayList<>(1);
 854                 bufs.add(buf);
 855                 int len2 = buf.length;
 856                 len2 = Math.max(len2, excess);
 857                 len2 = Math.max(len2, totalCount / 4);
 858                 buf = newMemberBuffer(Math.min(BUF_MAX, len2));
 859             }
 860             ArrayList<MemberName> result = new ArrayList<>(totalCount);
 861             if (bufs != null) {
 862                 for (MemberName[] buf0 : bufs) {
 863                     Collections.addAll(result, buf0);
 864                 }
 865             }
 866             result.addAll(Arrays.asList(buf).subList(0, bufCount));
 867             // Signature matching is not the same as type matching, since
 868             // one signature might correspond to several types.
 869             // So if matchType is a Class or MethodType, refilter the results.
 870             if (matchType != null && matchType != matchSig) {
 871                 for (Iterator<MemberName> it = result.iterator(); it.hasNext();) {
 872                     MemberName m = it.next();
 873                     if (!matchType.equals(m.getType()))
 874                         it.remove();
 875                 }
 876             }
 877             return result;
 878         }
 879         /** Produce a resolved version of the given member.
 880          *  Super types are searched (for inherited members) if {@code searchSupers} is true.
 881          *  Access checking is performed on behalf of the given {@code lookupClass}.
 882          *  If lookup fails or access is not permitted, null is returned.
 883          *  Otherwise a fresh copy of the given member is returned, with modifier bits filled in.
 884          */
 885         private MemberName resolve(byte refKind, MemberName ref, Class<?> lookupClass) {
 886             MemberName m = ref.clone();  // JVM will side-effect the ref
 887             assert(refKind == m.getReferenceKind());
 888             try {
 889                 m = MethodHandleNatives.resolve(m, lookupClass);
 890                 m.checkForTypeAlias();
 891                 m.resolution = null;
 892             } catch (LinkageError ex) {
 893                 // JVM reports that the "bytecode behavior" would get an error
 894                 assert(!m.isResolved());
 895                 m.resolution = ex;
 896                 return m;
 897             }
 898             assert(m.referenceKindIsConsistent());
 899             m.initResolved(true);
 900             assert(m.vminfoIsConsistent());
 901             return m;
 902         }
 903         /** Produce a resolved version of the given member.
 904          *  Super types are searched (for inherited members) if {@code searchSupers} is true.
 905          *  Access checking is performed on behalf of the given {@code lookupClass}.
 906          *  If lookup fails or access is not permitted, a {@linkplain ReflectiveOperationException} is thrown.
 907          *  Otherwise a fresh copy of the given member is returned, with modifier bits filled in.
 908          */
 909         public
 910         <NoSuchMemberException extends ReflectiveOperationException>
 911         MemberName resolveOrFail(byte refKind, MemberName m, Class<?> lookupClass,
 912                                  Class<NoSuchMemberException> nsmClass)
 913                 throws IllegalAccessException, NoSuchMemberException {
 914             MemberName result = resolve(refKind, m, lookupClass);
 915             if (result.isResolved())
 916                 return result;
 917             ReflectiveOperationException ex = result.makeAccessException();
 918             if (ex instanceof IllegalAccessException)  throw (IllegalAccessException) ex;
 919             throw nsmClass.cast(ex);
 920         }
 921         /** Produce a resolved version of the given member.
 922          *  Super types are searched (for inherited members) if {@code searchSupers} is true.
 923          *  Access checking is performed on behalf of the given {@code lookupClass}.
 924          *  If lookup fails or access is not permitted, return null.
 925          *  Otherwise a fresh copy of the given member is returned, with modifier bits filled in.
 926          */
 927         public
 928         MemberName resolveOrNull(byte refKind, MemberName m, Class<?> lookupClass) {
 929             MemberName result = resolve(refKind, m, lookupClass);
 930             if (result.isResolved())
 931                 return result;
 932             return null;
 933         }
 934         /** Return a list of all methods defined by the given class.
 935          *  Super types are searched (for inherited members) if {@code searchSupers} is true.
 936          *  Access checking is performed on behalf of the given {@code lookupClass}.
 937          *  Inaccessible members are not added to the last.
 938          */
 939         public List<MemberName> getMethods(Class<?> defc, boolean searchSupers,
 940                 Class<?> lookupClass) {
 941             return getMethods(defc, searchSupers, null, null, lookupClass);
 942         }
 943         /** Return a list of matching methods defined by the given class.
 944          *  Super types are searched (for inherited members) if {@code searchSupers} is true.
 945          *  Returned methods will match the name (if not null) and the type (if not null).
 946          *  Access checking is performed on behalf of the given {@code lookupClass}.
 947          *  Inaccessible members are not added to the last.
 948          */
 949         public List<MemberName> getMethods(Class<?> defc, boolean searchSupers,
 950                 String name, MethodType type, Class<?> lookupClass) {
 951             int matchFlags = IS_METHOD | (searchSupers ? SEARCH_ALL_SUPERS : 0);
 952             return getMembers(defc, name, type, matchFlags, lookupClass);
 953         }
 954         /** Return a list of all constructors defined by the given class.
 955          *  Access checking is performed on behalf of the given {@code lookupClass}.
 956          *  Inaccessible members are not added to the last.
 957          */
 958         public List<MemberName> getConstructors(Class<?> defc, Class<?> lookupClass) {
 959             return getMembers(defc, null, null, IS_CONSTRUCTOR, lookupClass);
 960         }
 961         /** Return a list of all fields defined by the given class.
 962          *  Super types are searched (for inherited members) if {@code searchSupers} is true.
 963          *  Access checking is performed on behalf of the given {@code lookupClass}.
 964          *  Inaccessible members are not added to the last.
 965          */
 966         public List<MemberName> getFields(Class<?> defc, boolean searchSupers,
 967                 Class<?> lookupClass) {
 968             return getFields(defc, searchSupers, null, null, lookupClass);
 969         }
 970         /** Return a list of all fields defined by the given class.
 971          *  Super types are searched (for inherited members) if {@code searchSupers} is true.
 972          *  Returned fields will match the name (if not null) and the type (if not null).
 973          *  Access checking is performed on behalf of the given {@code lookupClass}.
 974          *  Inaccessible members are not added to the last.
 975          */
 976         public List<MemberName> getFields(Class<?> defc, boolean searchSupers,
 977                 String name, Class<?> type, Class<?> lookupClass) {
 978             int matchFlags = IS_FIELD | (searchSupers ? SEARCH_ALL_SUPERS : 0);
 979             return getMembers(defc, name, type, matchFlags, lookupClass);
 980         }
 981         /** Return a list of all nested types defined by the given class.
 982          *  Super types are searched (for inherited members) if {@code searchSupers} is true.
 983          *  Access checking is performed on behalf of the given {@code lookupClass}.
 984          *  Inaccessible members are not added to the last.
 985          */
 986         public List<MemberName> getNestedTypes(Class<?> defc, boolean searchSupers,
 987                 Class<?> lookupClass) {
 988             int matchFlags = IS_TYPE | (searchSupers ? SEARCH_ALL_SUPERS : 0);
 989             return getMembers(defc, null, null, matchFlags, lookupClass);
 990         }
 991         private static MemberName[] newMemberBuffer(int length) {
 992             MemberName[] buf = new MemberName[length];
 993             // fill the buffer with dummy structs for the JVM to fill in
 994             for (int i = 0; i < length; i++)
 995                 buf[i] = new MemberName();
 996             return buf;
 997         }
 998     }
 999 
1000 //    static {
1001 //        System.out.println("Hello world!  My methods are:");
1002 //        System.out.println(Factory.INSTANCE.getMethods(MemberName.class, true, null));
1003 //    }
1004 }