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1   /*
2    * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
3    *
4    * This code is free software; you can redistribute it and/or modify it
5    * under the terms of the GNU General Public License version 2 only, as
6    * published by the Free Software Foundation.  Oracle designates this
7    * particular file as subject to the "Classpath" exception as provided
8    * by Oracle in the LICENSE file that accompanied this code.
9    *
10   * This code is distributed in the hope that it will be useful, but WITHOUT
11   * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12   * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
13   * version 2 for more details (a copy is included in the LICENSE file that
14   * accompanied this code).
15   *
16   * You should have received a copy of the GNU General Public License version
17   * 2 along with this work; if not, write to the Free Software Foundation,
18   * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
19   *
20   * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
21   * or visit www.oracle.com if you need additional information or have any
22   * questions.
23   */
24  
25  /*
26   * This file is available under and governed by the GNU General Public
27   * License version 2 only, as published by the Free Software Foundation.
28   * However, the following notice accompanied the original version of this
29   * file:
30   *
31   * ASM: a very small and fast Java bytecode manipulation framework
32   * Copyright (c) 2000-2011 INRIA, France Telecom
33   * All rights reserved.
34   *
35   * Redistribution and use in source and binary forms, with or without
36   * modification, are permitted provided that the following conditions
37   * are met:
38   * 1. Redistributions of source code must retain the above copyright
39   *    notice, this list of conditions and the following disclaimer.
40   * 2. Redistributions in binary form must reproduce the above copyright
41   *    notice, this list of conditions and the following disclaimer in the
42   *    documentation and/or other materials provided with the distribution.
43   * 3. Neither the name of the copyright holders nor the names of its
44   *    contributors may be used to endorse or promote products derived from
45   *    this software without specific prior written permission.
46   *
47   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
48   * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
49   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
50   * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
51   * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
52   * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
53   * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
54   * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
55   * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
56   * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
57   * THE POSSIBILITY OF SUCH DAMAGE.
58   */
59  package jdk.internal.org.objectweb.asm;
60  
61  /**
62   * A visitor to visit a Java field. The methods of this class must be called in
63   * the following order: ( <tt>visitAnnotation</tt> |
64   * <tt>visitTypeAnnotation</tt> | <tt>visitAttribute</tt> )* <tt>visitEnd</tt>.
65   *
66   * @author Eric Bruneton
67   */
68  public abstract class FieldVisitor {
69  
70      /**
71       * The ASM API version implemented by this visitor. The value of this field
72       * must be one of {@link Opcodes#ASM4} or {@link Opcodes#ASM5}.
73       */
74      protected final int api;
75  
76      /**
77       * The field visitor to which this visitor must delegate method calls. May
78       * be null.
79       */
80      protected FieldVisitor fv;
81  
82      /**
83       * Constructs a new {@link FieldVisitor}.
84       *
85       * @param api
86       *            the ASM API version implemented by this visitor. Must be one
87       *            of {@link Opcodes#ASM4} or {@link Opcodes#ASM5}.
88       */
89      public FieldVisitor(final int api) {
90          this(api, null);
91      }
92  
93      /**
94       * Constructs a new {@link FieldVisitor}.
95       *
96       * @param api
97       *            the ASM API version implemented by this visitor. Must be one
98       *            of {@link Opcodes#ASM4} or {@link Opcodes#ASM5}.
99       * @param fv
100      *            the field visitor to which this visitor must delegate method
101      *            calls. May be null.
102      */
103     public FieldVisitor(final int api, final FieldVisitor fv) {
104         if (api != Opcodes.ASM4 && api != Opcodes.ASM5) {
105             throw new IllegalArgumentException();
106         }
107         this.api = api;
108         this.fv = fv;
109     }
110 
111     /**
112      * Visits an annotation of the field.
113      *
114      * @param desc
115      *            the class descriptor of the annotation class.
116      * @param visible
117      *            <tt>true</tt> if the annotation is visible at runtime.
118      * @return a visitor to visit the annotation values, or <tt>null</tt> if
119      *         this visitor is not interested in visiting this annotation.
120      */
121     public AnnotationVisitor visitAnnotation(String desc, boolean visible) {
122         if (fv != null) {
123             return fv.visitAnnotation(desc, visible);
124         }
125         return null;
126     }
127 
128     /**
129      * Visits an annotation on the type of the field.
130      *
131      * @param typeRef
132      *            a reference to the annotated type. The sort of this type
133      *            reference must be {@link TypeReference#FIELD FIELD}. See
134      *            {@link TypeReference}.
135      * @param typePath
136      *            the path to the annotated type argument, wildcard bound, array
137      *            element type, or static inner type within 'typeRef'. May be
138      *            <tt>null</tt> if the annotation targets 'typeRef' as a whole.
139      * @param desc
140      *            the class descriptor of the annotation class.
141      * @param visible
142      *            <tt>true</tt> if the annotation is visible at runtime.
143      * @return a visitor to visit the annotation values, or <tt>null</tt> if
144      *         this visitor is not interested in visiting this annotation.
145      */
146     public AnnotationVisitor visitTypeAnnotation(int typeRef,
147             TypePath typePath, String desc, boolean visible) {
148         if (api < Opcodes.ASM5) {
149             throw new RuntimeException();
150         }
151         if (fv != null) {
152             return fv.visitTypeAnnotation(typeRef, typePath, desc, visible);
153         }
154         return null;
155     }
156 
157     /**
158      * Visits a non standard attribute of the field.
159      *
160      * @param attr
161      *            an attribute.
162      */
163     public void visitAttribute(Attribute attr) {
164         if (fv != null) {
165             fv.visitAttribute(attr);
166         }
167     }
168 
169     /**
170      * Visits the end of the field. This method, which is the last one to be
171      * called, is used to inform the visitor that all the annotations and
172      * attributes of the field have been visited.
173      */
174     public void visitEnd() {
175         if (fv != null) {
176             fv.visitEnd();
177         }
178     }
179 }