Descriptor.java revision 3170:dc017a37aac5 
1/*
2 * Copyright (c) 2007, 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.classfile;
27
28import java.io.IOException;
29
30/**
31 * See JVMS, section 4.4.
32 *
33 *  <p><b>This is NOT part of any supported API.
34 *  If you write code that depends on this, you do so at your own risk.
35 *  This code and its internal interfaces are subject to change or
36 *  deletion without notice.</b>
37 */
38public class Descriptor {
39    public static class InvalidDescriptor extends DescriptorException {
40        private static final long serialVersionUID = 1L;
41        InvalidDescriptor(String desc) {
42            this.desc = desc;
43            this.index = -1;
44        }
45
46        InvalidDescriptor(String desc, int index) {
47            this.desc = desc;
48            this.index = index;
49        }
50
51        @Override
52        public String getMessage() {
53            // i18n
54            if (index == -1)
55                return "invalid descriptor \"" + desc + "\"";
56            else
57                return "descriptor is invalid at offset " + index + " in \"" + desc + "\"";
58        }
59
60        public final String desc;
61        public final int index;
62
63    }
64
65    public Descriptor(ClassReader cr) throws IOException {
66        this(cr.readUnsignedShort());
67    }
68
69    public Descriptor(int index) {
70        this.index = index;
71
72    }
73
74    public String getValue(ConstantPool constant_pool) throws ConstantPoolException {
75        return constant_pool.getUTF8Value(index);
76    }
77
78    public int getParameterCount(ConstantPool constant_pool)
79            throws ConstantPoolException, InvalidDescriptor {
80        String desc = getValue(constant_pool);
81        int end = desc.indexOf(")");
82        if (end == -1)
83            throw new InvalidDescriptor(desc);
84        parse(desc, 0, end + 1);
85        return count;
86
87    }
88
89    public String getParameterTypes(ConstantPool constant_pool)
90            throws ConstantPoolException, InvalidDescriptor {
91        String desc = getValue(constant_pool);
92        int end = desc.indexOf(")");
93        if (end == -1)
94            throw new InvalidDescriptor(desc);
95        return parse(desc, 0, end + 1);
96    }
97
98    public String getReturnType(ConstantPool constant_pool)
99            throws ConstantPoolException, InvalidDescriptor {
100        String desc = getValue(constant_pool);
101        int end = desc.indexOf(")");
102        if (end == -1)
103            throw new InvalidDescriptor(desc);
104        return parse(desc, end + 1, desc.length());
105    }
106
107    public String getFieldType(ConstantPool constant_pool)
108            throws ConstantPoolException, InvalidDescriptor {
109        String desc = getValue(constant_pool);
110        return parse(desc, 0, desc.length());
111    }
112
113    private String parse(String desc, int start, int end)
114            throws InvalidDescriptor {
115        int p = start;
116        StringBuilder sb = new StringBuilder();
117        int dims = 0;
118        count = 0;
119
120        while (p < end) {
121            String type;
122            char ch;
123            switch (ch = desc.charAt(p++)) {
124                case '(':
125                    sb.append('(');
126                    continue;
127
128                case ')':
129                    sb.append(')');
130                    continue;
131
132                case '[':
133                    dims++;
134                    continue;
135
136                case 'B':
137                    type = "byte";
138                    break;
139
140                case 'C':
141                    type = "char";
142                    break;
143
144                case 'D':
145                    type = "double";
146                    break;
147
148                case 'F':
149                    type = "float";
150                    break;
151
152                case 'I':
153                    type = "int";
154                    break;
155
156                case 'J':
157                    type = "long";
158                    break;
159
160                case 'L':
161                    int sep = desc.indexOf(';', p);
162                    if (sep == -1)
163                        throw new InvalidDescriptor(desc, p - 1);
164                    type = desc.substring(p, sep).replace('/', '.');
165                    p = sep + 1;
166                    break;
167
168                case 'S':
169                    type = "short";
170                    break;
171
172                case 'Z':
173                    type = "boolean";
174                    break;
175
176                case 'V':
177                    type = "void";
178                    break;
179
180                default:
181                    throw new InvalidDescriptor(desc, p - 1);
182            }
183
184            if (sb.length() > 1 && sb.charAt(0) == '(')
185                sb.append(", ");
186            sb.append(type);
187            for ( ; dims > 0; dims-- )
188                sb.append("[]");
189
190            count++;
191        }
192
193        return sb.toString();
194    }
195
196    public final int index;
197    private int count;
198}
199