TargetType.java revision 2628:8df25ec8c930 
1/*
2 * Copyright (c) 2008, 2013, 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
26package com.sun.tools.javac.code;
27
28import com.sun.tools.javac.util.Assert;
29
30/**
31 * Describes the type of program element an extended annotation (or extended
32 * compound attribute) targets.
33 *
34 * By comparison, a Tree.Kind has enum values for all elements in the AST, and
35 * it does not provide enough resolution for type arguments (i.e., whether an
36 * annotation targets a type argument in a local variable, method return type,
37 * or a typecast).
38 *
39 *  <p><b>This is NOT part of any supported API.
40 *  If you write code that depends on this, you do so at your own risk.
41 *  This code and its internal interfaces are subject to change or
42 *  deletion without notice.</b>
43 */
44// Code duplicated in com.sun.tools.classfile.TypeAnnotation.TargetType
45public enum TargetType {
46    /** For annotations on a class type parameter declaration. */
47    CLASS_TYPE_PARAMETER(0x00),
48
49    /** For annotations on a method type parameter declaration. */
50    METHOD_TYPE_PARAMETER(0x01),
51
52    /** For annotations on the type of an "extends" or "implements" clause. */
53    CLASS_EXTENDS(0x10),
54
55    /** For annotations on a bound of a type parameter of a class. */
56    CLASS_TYPE_PARAMETER_BOUND(0x11),
57
58    /** For annotations on a bound of a type parameter of a method. */
59    METHOD_TYPE_PARAMETER_BOUND(0x12),
60
61    /** For annotations on a field. */
62    FIELD(0x13),
63
64    /** For annotations on a method return type. */
65    METHOD_RETURN(0x14),
66
67    /** For annotations on the method receiver. */
68    METHOD_RECEIVER(0x15),
69
70    /** For annotations on a method parameter. */
71    METHOD_FORMAL_PARAMETER(0x16),
72
73    /** For annotations on a throws clause in a method declaration. */
74    THROWS(0x17),
75
76    /** For annotations on a local variable. */
77    LOCAL_VARIABLE(0x40, true),
78
79    /** For annotations on a resource variable. */
80    RESOURCE_VARIABLE(0x41, true),
81
82    /** For annotations on an exception parameter. */
83    EXCEPTION_PARAMETER(0x42, true),
84
85    /** For annotations on a type test. */
86    INSTANCEOF(0x43, true),
87
88    /** For annotations on an object creation expression. */
89    NEW(0x44, true),
90
91    /** For annotations on a constructor reference receiver. */
92    CONSTRUCTOR_REFERENCE(0x45, true),
93
94    /** For annotations on a method reference receiver. */
95    METHOD_REFERENCE(0x46, true),
96
97    /** For annotations on a typecast. */
98    CAST(0x47, true),
99
100    /** For annotations on a type argument of an object creation expression. */
101    CONSTRUCTOR_INVOCATION_TYPE_ARGUMENT(0x48, true),
102
103    /** For annotations on a type argument of a method call. */
104    METHOD_INVOCATION_TYPE_ARGUMENT(0x49, true),
105
106    /** For annotations on a type argument of a constructor reference. */
107    CONSTRUCTOR_REFERENCE_TYPE_ARGUMENT(0x4A, true),
108
109    /** For annotations on a type argument of a method reference. */
110    METHOD_REFERENCE_TYPE_ARGUMENT(0x4B, true),
111
112    /** For annotations with an unknown target. */
113    UNKNOWN(0xFF);
114
115    private static final int MAXIMUM_TARGET_TYPE_VALUE = 0x4B;
116
117    private final int targetTypeValue;
118    private final boolean isLocal;
119
120    private TargetType(int targetTypeValue) {
121        this(targetTypeValue, false);
122    }
123
124    private TargetType(int targetTypeValue, boolean isLocal) {
125        if (targetTypeValue < 0
126                || targetTypeValue > 255)
127                Assert.error("Attribute type value needs to be an unsigned byte: " + String.format("0x%02X", targetTypeValue));
128        this.targetTypeValue = targetTypeValue;
129        this.isLocal = isLocal;
130    }
131
132    /**
133     * Returns whether or not this TargetType represents an annotation whose
134     * target is exclusively a tree in a method body
135     *
136     * Note: wildcard bound targets could target a local tree and a class
137     * member declaration signature tree
138     */
139    public boolean isLocal() {
140        return isLocal;
141    }
142
143    public int targetTypeValue() {
144        return this.targetTypeValue;
145    }
146
147    private static final TargetType[] targets;
148
149    static {
150        targets = new TargetType[MAXIMUM_TARGET_TYPE_VALUE + 1];
151        TargetType[] alltargets = values();
152        for (TargetType target : alltargets) {
153            if (target.targetTypeValue != UNKNOWN.targetTypeValue)
154                targets[target.targetTypeValue] = target;
155        }
156        for (int i = 0; i <= MAXIMUM_TARGET_TYPE_VALUE; ++i) {
157            if (targets[i] == null)
158                targets[i] = UNKNOWN;
159        }
160    }
161
162    public static boolean isValidTargetTypeValue(int tag) {
163        if (tag == UNKNOWN.targetTypeValue)
164            return true;
165
166        return (tag >= 0 && tag < targets.length);
167    }
168
169    public static TargetType fromTargetTypeValue(int tag) {
170        if (tag == UNKNOWN.targetTypeValue)
171            return UNKNOWN;
172
173        if (tag < 0 || tag >= targets.length)
174            Assert.error("Unknown TargetType: " + tag);
175        return targets[tag];
176    }
177}
178