1 /*
2 * Copyright (c) 2018, 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.
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
25 /*
26 * @test
27 * @summary test MethodHandle and VarHandle of value classes
28 * @enablePreview
29 * @run junit/othervm MethodHandleTest
30 */
31
32 import java.lang.invoke.*;
33 import java.lang.reflect.Field;
34 import java.lang.reflect.Modifier;
35 import java.util.List;
36 import java.util.Set;
37 import java.util.stream.Stream;
38
39 import jdk.internal.value.ValueClass;
40 import jdk.internal.vm.annotation.ImplicitlyConstructible;
41 import jdk.internal.vm.annotation.NullRestricted;
42 import org.junit.jupiter.params.ParameterizedTest;
43 import org.junit.jupiter.params.provider.Arguments;
44 import org.junit.jupiter.params.provider.MethodSource;
45
46 import static org.junit.jupiter.api.Assertions.*;
47
48 public class MethodHandleTest {
49 @ImplicitlyConstructible
50 static value class Point {
51 public int x;
52 public int y;
53 Point(int x, int y) {
54 this.x = x;
55 this.y = y;
56 }
57 }
58
59 @ImplicitlyConstructible
60 static value class Line {
61 @NullRestricted
62 Point p1;
63 @NullRestricted
64 Point p2;
65
66 Line(int x1, int y1, int x2, int y2) {
67 this.p1 = new Point(x1, y1);
68 this.p2 = new Point(x2, y2);
69 }
70 }
71
72 static class Ref {
73 @NullRestricted
74 Point p;
75 Line l;
76 List<String> list;
77 ValueOptional vo;
78
79 Ref(Point p, Line l) {
80 this.p = p;
81 this.l = l;
82 }
83 }
84
85 @ImplicitlyConstructible
86 static value class ValueOptional {
87 private Object o;
88 public ValueOptional(Object o) {
89 this.o = o;
90 }
91 }
92
93 private static final MethodHandles.Lookup LOOKUP = MethodHandles.lookup();
94
95 static final Point P = new Point(1, 2);
96 static final Line L = new Line(1, 2, 3, 4);
97 static final Ref R = new Ref(P, null);
98
99 static Stream<Arguments> fields() {
100 return Stream.of(
101 // value class with int fields
102 Arguments.of("MethodHandleTest$Point", P, Set.of("x", "y")),
103 // value class whose fields are null-restricted and of value class
104 Arguments.of("MethodHandleTest$Line", L, Set.of("p1", "p2")),
105 // identity class whose non-final fields are of value type,
106 Arguments.of("MethodHandleTest$Ref", R, Set.of("p", "l", "list", "vo"))
107 );
108 }
109
110 /**
111 * Test MethodHandle invocation on the fields of a given class.
112 * MethodHandle produced by Lookup::unreflectGetter, Lookup::findGetter,
113 * Lookup::findVarHandle.
114 */
115 @ParameterizedTest
116 @MethodSource("fields")
117 public void testFieldGetter(String cn, Object o, Set<String> fields) throws Throwable {
118 Class<?> c = Class.forName(cn);
119 for (String name : fields) {
120 Field f = c.getDeclaredField(name);
121 var mh = LOOKUP.findGetter(c, f.getName(), f.getType());
122 var v1 = mh.invoke(o);
123
124 var vh = LOOKUP.findVarHandle(c, f.getName(), f.getType());
125 var v2 = vh.get(o);
126
127 var mh3 = LOOKUP.unreflectGetter(f);
128 var v3 = mh3.invoke(o);
129
130 if (c.isValue())
131 ensureImmutable(f, o);
132 }
133 }
134
135 static Stream<Arguments> setters() {
136 return Stream.of(
137 Arguments.of(Ref.class, R, "p", true),
138 Arguments.of(Ref.class, R, "l", false),
139 Arguments.of(Ref.class, R, "list", false),
140 Arguments.of(Ref.class, R, "vo", false)
141 );
142 }
143 @ParameterizedTest
144 @MethodSource("setters")
145 public void testFieldSetter(Class<?> cls, Object o, String name, boolean nullRestricted) throws Throwable {
146 Field f = cls.getDeclaredField(name);
147 var mh = LOOKUP.findSetter(cls, f.getName(), f.getType());
148 var vh = LOOKUP.findVarHandle(cls, f.getName(), f.getType());
149 var mh3 = LOOKUP.unreflectSetter(f);
150
151 if (nullRestricted) {
152 assertThrows(NullPointerException.class, () -> mh.invoke(o, null));
153 assertThrows(NullPointerException.class, () -> vh.set(o, null));
154 assertThrows(NullPointerException.class, () -> mh3.invoke(o, null));
155 } else {
156 mh.invoke(o, null);
157 vh.set(o, null);
158 mh3.invoke(o, null);
159 }
160 }
161
162 static Stream<Arguments> arrays() throws Throwable {
163 return Stream.of(
164 Arguments.of(Point[].class, newArray(Point[].class), P, false),
165 Arguments.of(Point[].class, newNullRestrictedArray(Point.class), P, true),
166 Arguments.of(Line[].class, newArray(Line[].class), L, false),
167 Arguments.of(Line[].class, newNullRestrictedArray(Line.class), L, true),
168 Arguments.of(Ref[].class, newArray(Ref[].class), R, false)
169 );
170 }
171
172 private static final int ARRAY_SIZE = 5;
173 private static Object[] newArray(Class<?> arrayClass) throws Throwable {
174 MethodHandle ctor = MethodHandles.arrayConstructor(arrayClass);
175 return (Object[])ctor.invoke(ARRAY_SIZE);
176 }
177 private static Object[] newNullRestrictedArray(Class<?> componentClass) throws Throwable {
178 return ValueClass.newNullRestrictedArray(componentClass, ARRAY_SIZE);
179 }
180
181 @ParameterizedTest
182 @MethodSource("arrays")
183 public void testArrayElementSetterAndGetter(Class<?> arrayClass, Object[] array, Object element, boolean nullRestricted) throws Throwable {
184 MethodHandle setter = MethodHandles.arrayElementSetter(array.getClass());
185 MethodHandle getter = MethodHandles.arrayElementGetter(array.getClass());
186 VarHandle vh = MethodHandles.arrayElementVarHandle(arrayClass);
187 Class<?> componentType = arrayClass.getComponentType();
188
189 for (int i=0; i < ARRAY_SIZE; i++) {
190 var v = getter.invoke(array, i);
191 if (nullRestricted) {
192 assertTrue(v == ValueClass.zeroInstance(componentType));
193 } else {
194 assertTrue(v == null);
195 }
196 }
197 for (int i=0; i < ARRAY_SIZE; i++) {
198 setter.invoke(array, i, element);
199 assertTrue(getter.invoke(array, i) == element);
200 }
201 // set an array element to null
202 if (nullRestricted) {
203 assertTrue(vh.get(array, 1) != null);
204 assertThrows(NullPointerException.class, () -> setter.invoke(array, 1, null));
205 assertThrows(NullPointerException.class, () -> vh.set(array, 1, null));
206 } else {
207 setter.invoke(array, 1, null);
208 assertNull(getter.invoke(array, 1));
209 vh.set(array, 1, null);
210 }
211 }
212
213 static void ensureImmutable(Field f, Object o) throws Throwable {
214 Class<?> c = f.getDeclaringClass();
215 assertTrue(Modifier.isFinal(f.getModifiers()));
216 assertFalse(Modifier.isStatic(f.getModifiers()));
217 assertTrue(f.trySetAccessible());
218
219 Object v = f.get(o);
220
221 assertThrows(IllegalAccessException.class, () -> LOOKUP.findSetter(c, f.getName(), f.getType()));
222 assertThrows(IllegalAccessException.class, () -> LOOKUP.unreflectSetter(f));
223 VarHandle vh = LOOKUP.findVarHandle(c, f.getName(), f.getType());
224
225 // test var handle
226 assertThrows(UnsupportedOperationException.class, () -> vh.set(o, v));
227 }
228 }