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
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24 */
25 package java.lang.constant;
26
27 import java.lang.invoke.MethodHandle;
28 import java.lang.invoke.MethodHandleInfo;
29 import java.lang.invoke.MethodHandles;
30
31 import static java.lang.invoke.MethodHandleInfo.REF_getField;
32 import static java.lang.invoke.MethodHandleInfo.REF_getStatic;
33 import static java.lang.invoke.MethodHandleInfo.REF_invokeInterface;
34 import static java.lang.invoke.MethodHandleInfo.REF_invokeSpecial;
35 import static java.lang.invoke.MethodHandleInfo.REF_invokeStatic;
36 import static java.lang.invoke.MethodHandleInfo.REF_invokeVirtual;
37 import static java.lang.invoke.MethodHandleInfo.REF_newInvokeSpecial;
38 import static java.lang.invoke.MethodHandleInfo.REF_putField;
39 import static java.lang.invoke.MethodHandleInfo.REF_putStatic;
40
41 /**
42 * A <a href="package-summary.html#nominal">nominal descriptor</a> for a direct
43 * {@link MethodHandle}. A {@linkplain DirectMethodHandleDescImpl} corresponds to
44 * a {@code Constant_MethodHandle_info} entry in the constant pool of a classfile.
45 *
46 * @apiNote In the future, if the Java language permits, {@linkplain DirectMethodHandleDesc}
47 * may become a {@code sealed} interface, which would prohibit subclassing except
48 * by explicitly permitted types. Non-platform classes should not implement
49 * {@linkplain DirectMethodHandleDesc} directly.
50 */
51 public interface DirectMethodHandleDesc extends MethodHandleDesc {
52 /**
53 * Kinds of method handles that can be described with {@linkplain DirectMethodHandleDesc}.
54 */
55 enum Kind {
56 /** A method handle for a method invoked as with {@code invokestatic} */
57 STATIC(REF_invokeStatic),
58 /** A method handle for a method invoked as with {@code invokestatic} */
59 INTERFACE_STATIC(REF_invokeStatic, true),
60 /** A method handle for a method invoked as with {@code invokevirtual} */
61 VIRTUAL(REF_invokeVirtual),
62 /** A method handle for a method invoked as with {@code invokeinterface} */
63 INTERFACE_VIRTUAL(REF_invokeInterface, true),
64 /** A method handle for a method invoked as with {@code invokespecial} */
65 SPECIAL(REF_invokeSpecial),
66 /** A method handle for an interface method invoked as with {@code invokespecial} */
67 INTERFACE_SPECIAL(REF_invokeSpecial, true),
68 /** A method handle for a constructor */
69 CONSTRUCTOR(REF_newInvokeSpecial),
70 /** A method handle for a read accessor for an instance field */
71 GETTER(REF_getField),
72 /** A method handle for a write accessor for an instance field */
73 SETTER(REF_putField),
74 /** A method handle for a read accessor for a static field */
75 STATIC_GETTER(REF_getStatic),
76 /** A method handle for a write accessor for a static field */
77 STATIC_SETTER(REF_putStatic);
78
79 /** The corresponding {@code refKind} value for this kind of method handle,
80 * as defined by {@link MethodHandleInfo}
81 */
82 public final int refKind;
83
84 /** Is this an interface
85 */
86 public final boolean isInterface;
87 Kind(int refKind) {
88 this(refKind, false);
89 }
90
91 Kind(int refKind, boolean isInterface) { this.refKind = refKind; this.isInterface = isInterface; }
92 }
93 /**
94 * Return the {@code kind} of the method handle described by this nominal
95 * descriptor.
96 *
97 * @return the {@link Kind}
98 */
99 Kind kind();
100
101 /**
102 * Return the {@code refKind} of the method handle described by this nominal
103 * reference, as defined by {@link MethodHandleInfo}.
104 *
105 * @return the reference kind
106 */
107 int refKind();
108
109 /**
110 * Indicates if the method is declared by an interface
111 *
112 * @return true if the method is declared by an interface
113 */
114 boolean isOwnerInterface();
115
116 /**
117 * Return a {@link ClassDesc} describing the class declaring the
118 * method or field described by this nominal descriptor.
119 *
120 * @return the class declaring the method or field
121 */
122 ClassDesc owner();
123
124 /**
125 * Return the name of the method or field described by this nominal descriptor.
126 *
127 * @return the name of the method or field
128 */
129 String methodName();
130
131 /**
132 * Return a {@link MethodTypeDesc} describing the invocation type of the
133 * method handle described by this nominal descriptor
134 *
135 * @return the method type
136 */
137 MethodTypeDesc methodType();
138
139 /**
140 * Create a {@linkplain DirectMethodHandleDesc} given descriptor strings
141 * for its components. Suitable for use as a constant bootstrap method
142 * for representing a {@linkplain DirectMethodHandleDesc} in the constant
143 * pool of a classfile.
144 *
145 * @param bsmKindName The name of an {@code enum} constant from {@link Kind}
146 * @param memberOwner A field type descriptor for the class declaring the
147 * method, field, or constructor, as per JVMS 4.3.2
148 * @param memberName The name of the method or field, as per JVMS 4.2.2
149 * @param memberType A method type descriptor for the method handle being
150 * described, as per JVMS 4.3.3
151 * @return the {@linkplain MethodHandleDesc}
152 * @jvms 4.2.2 Unqualified Names
153 * @jvms 4.3.2 Field Descriptors
154 * @jvms 4.3.3 Method Descriptors
155 */
156 static DirectMethodHandleDesc ofDescriptor(String bsmKindName,
157 String memberOwner,
158 String memberName,
159 String memberType) {
160 return MethodHandleDesc.of(Kind.valueOf(bsmKindName),
161 ClassDesc.ofDescriptor(memberOwner), memberName,
162 MethodTypeDesc.ofDescriptor(memberType));
163 }
164 }