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.MethodHandles;
28 import java.lang.invoke.MethodType;
29 import java.util.Arrays;
30 import java.util.List;
31 import java.util.Optional;
32
33 import static java.util.Objects.requireNonNull;
34
35 /**
36 * A <a href="package-summary.html#nominal">nominal descriptor</a> for a
37 * {@link MethodType}. A {@linkplain MethodTypeDescImpl} corresponds to a
38 * {@code Constant_MethodType_info} entry in the constant pool of a classfile.
39 */
40 final class MethodTypeDescImpl implements MethodTypeDesc {
41 private final ClassDesc returnType;
42 private final ClassDesc[] argTypes;
43
44 /**
45 * Construct a {@linkplain MethodTypeDesc} with the specified return type
46 * and parameter types
47 *
48 * @param returnType a {@link ClassDesc} describing the return type
49 * @param argTypes {@link ClassDesc}s describing the parameter types
50 */
51 MethodTypeDescImpl(ClassDesc returnType, ClassDesc[] argTypes) {
52 this.returnType = requireNonNull(returnType);
53 this.argTypes = requireNonNull(argTypes);
54
55 for (ClassDesc cr : argTypes)
56 if (cr.isPrimitive() && cr.descriptorString().equals("V"))
57 throw new IllegalArgumentException("Void parameters not permitted");
58 }
59
60 /**
61 * Create a {@linkplain MethodTypeDescImpl} given a method descriptor string.
62 *
63 * @param descriptor the method descriptor string, as per JVMS 4.3.3
64 * @return a {@linkplain MethodTypeDescImpl} describing the desired method type
65 * @throws IllegalArgumentException if the descriptor string is not a valid
66 * method descriptor
67 * @jvms 4.3.3 Method Descriptors
68 */
69 static MethodTypeDescImpl ofDescriptor(String descriptor) {
70 requireNonNull(descriptor);
71 List<String> types = ConstantUtils.parseMethodDescriptor(descriptor);
72 ClassDesc[] paramTypes = types.stream().skip(1).map(ClassDesc::ofDescriptor).toArray(ClassDesc[]::new);
73 return new MethodTypeDescImpl(ClassDesc.ofDescriptor(types.get(0)), paramTypes);
74 }
75
76 @Override
77 public ClassDesc returnType() {
78 return returnType;
79 }
80
81 @Override
82 public int parameterCount() {
83 return argTypes.length;
84 }
85
86 @Override
87 public ClassDesc parameterType(int index) {
88 return argTypes[index];
89 }
90
91 @Override
92 public List<ClassDesc> parameterList() {
93 return List.of(argTypes);
94 }
95
96 @Override
97 public ClassDesc[] parameterArray() {
98 return argTypes.clone();
99 }
100
101 @Override
102 public MethodTypeDesc changeReturnType(ClassDesc returnType) {
103 return MethodTypeDesc.of(returnType, argTypes);
104 }
105
106 @Override
107 public MethodTypeDesc changeParameterType(int index, ClassDesc paramType) {
108 ClassDesc[] newArgs = argTypes.clone();
109 newArgs[index] = paramType;
110 return MethodTypeDesc.of(returnType, newArgs);
111 }
112
113 @Override
114 public MethodTypeDesc dropParameterTypes(int start, int end) {
115 if (start < 0 || start >= argTypes.length || end < 0 || end > argTypes.length)
116 throw new IndexOutOfBoundsException();
117 else if (start > end)
118 throw new IllegalArgumentException(String.format("Range (%d, %d) not valid for size %d", start, end, argTypes.length));
119 ClassDesc[] newArgs = new ClassDesc[argTypes.length - (end - start)];
120 System.arraycopy(argTypes, 0, newArgs, 0, start);
121 System.arraycopy(argTypes, end, newArgs, start, argTypes.length - end);
122 return MethodTypeDesc.of(returnType, newArgs);
123 }
124
125 @Override
126 public MethodTypeDesc insertParameterTypes(int pos, ClassDesc... paramTypes) {
127 if (pos < 0 || pos > argTypes.length)
128 throw new IndexOutOfBoundsException(pos);
129 ClassDesc[] newArgs = new ClassDesc[argTypes.length + paramTypes.length];
130 System.arraycopy(argTypes, 0, newArgs, 0, pos);
131 System.arraycopy(paramTypes, 0, newArgs, pos, paramTypes.length);
132 System.arraycopy(argTypes, pos, newArgs, pos+paramTypes.length, argTypes.length - pos);
133 return MethodTypeDesc.of(returnType, newArgs);
134 }
135
136 @Override
137 public MethodType resolveConstantDesc(MethodHandles.Lookup lookup) {
138 return MethodType.fromMethodDescriptorString(descriptorString(), lookup.lookupClass().getClassLoader());
139 }
140
141 @Override
142 public Optional<? extends ConstantDesc<ConstantDesc<MethodType>>> describeConstable() {
143 return Optional.of(DynamicConstantDesc.ofSymbolic(this));
144 }
145
146 @Override
147 public boolean equals(Object o) {
148 if (this == o) return true;
149 if (o == null || getClass() != o.getClass()) return false;
150
151 MethodTypeDescImpl constant = (MethodTypeDescImpl) o;
152
153 return returnType.equals(constant.returnType)
154 && Arrays.equals(argTypes, constant.argTypes);
155 }
156
157 @Override
158 public int hashCode() {
159 int result = returnType.hashCode();
160 result = 31 * result + Arrays.hashCode(argTypes);
161 return result;
162 }
163
164 @Override
165 public String toString() {
166 return String.format("MethodTypeDesc[%s]", displayDescriptor());
167 }
168 }