1 /* 2 * Copyright (c) 2024, 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.reflect.code.type; 27 28 import java.lang.constant.ClassDesc; 29 import java.lang.invoke.MethodHandles.Lookup; 30 import java.lang.reflect.Type; 31 import java.util.List; 32 import java.util.Objects; 33 34 /** 35 * A wildcard type. 36 */ 37 public final class WildcardType implements JavaType { 38 39 final BoundKind kind; 40 final JavaType boundType; 41 42 WildcardType(BoundKind kind, JavaType boundType) { 43 this.kind = kind; 44 this.boundType = boundType; 45 } 46 47 @Override 48 public Type resolve(Lookup lookup) throws ReflectiveOperationException { 49 Type[] upperBounds = kind == BoundKind.EXTENDS ? 50 new Type[] { boundType.resolve(lookup) } : new Type[] { Object.class }; 51 Type[] lowerBounds = kind == BoundKind.SUPER ? 52 new Type[] { boundType.resolve(lookup) } : new Type[0]; 53 return makeReflectiveWildcard(upperBounds, lowerBounds); 54 } 55 56 // Copied code in jdk.compiler module throws UOE 57 private static java.lang.reflect.WildcardType makeReflectiveWildcard(Type[] upper, Type[] lower) { 58 /*__throw new UnsupportedOperationException();__*/ return sun.reflect.generics.reflectiveObjects.WildcardTypeImpl.make(upper, lower); 59 } 60 61 /** 62 * {@return the wildcard type's bound type} 63 */ 64 public JavaType boundType() { 65 return boundType; 66 } 67 68 /** 69 * {@return the wildcard type's bound kind} 70 */ 71 public BoundKind boundKind() { 72 return kind; 73 } 74 75 @Override 76 public ExternalizedTypeElement externalize() { 77 String prefix = kind == BoundKind.EXTENDS ? "+" : "-"; 78 return new ExternalizedTypeElement(prefix, List.of(boundType.externalize())); 79 } 80 81 @Override 82 public String toString() { 83 return externalize().toString(); 84 } 85 86 @Override 87 public boolean equals(Object o) { 88 if (this == o) return true; 89 return o instanceof WildcardType that && 90 kind.equals(that.kind) && 91 boundType.equals(that.boundType); 92 } 93 94 @Override 95 public int hashCode() { 96 return Objects.hash(boundType, kind); 97 } 98 99 @Override 100 public JavaType erasure() { 101 throw new UnsupportedOperationException("Wildcard type"); 102 } 103 104 @Override 105 public JavaType toBasicType() { 106 throw new UnsupportedOperationException("Wildcard type"); 107 } 108 109 @Override 110 public ClassDesc toNominalDescriptor() { 111 throw new UnsupportedOperationException("Wildcard type"); 112 } 113 114 /** 115 * The bound kind of a wildcard type. 116 */ 117 public enum BoundKind { 118 /** A bound kind representing a {@code ? extends} wildcard type*/ 119 EXTENDS, 120 /** A bound kind representing a {@code ? super} wildcard type*/ 121 SUPER 122 } 123 }