001// ASM: a very small and fast Java bytecode manipulation framework 002// Copyright (c) 2000-2011 INRIA, France Telecom 003// All rights reserved. 004// 005// Redistribution and use in source and binary forms, with or without 006// modification, are permitted provided that the following conditions 007// are met: 008// 1. Redistributions of source code must retain the above copyright 009// notice, this list of conditions and the following disclaimer. 010// 2. Redistributions in binary form must reproduce the above copyright 011// notice, this list of conditions and the following disclaimer in the 012// documentation and/or other materials provided with the distribution. 013// 3. Neither the name of the copyright holders nor the names of its 014// contributors may be used to endorse or promote products derived from 015// this software without specific prior written permission. 016// 017// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 018// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 019// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 020// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE 021// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 022// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 023// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 024// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 025// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 026// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF 027// THE POSSIBILITY OF SUCH DAMAGE. 028package org.springframework.asm; 029 030/** 031 * A visitor to visit a Java field. The methods of this class must be called in the following order: 032 * ( {@code visitAnnotation} | {@code visitTypeAnnotation} | {@code visitAttribute} )* {@code 033 * visitEnd}. 034 * 035 * @author Eric Bruneton 036 */ 037public abstract class FieldVisitor { 038 039 /** 040 * The ASM API version implemented by this visitor. The value of this field must be one of {@link 041 * Opcodes#ASM4}, {@link Opcodes#ASM5}, {@link Opcodes#ASM6} or {@link Opcodes#ASM7}. 042 */ 043 protected final int api; 044 045 /** The field visitor to which this visitor must delegate method calls. May be {@literal null}. */ 046 protected FieldVisitor fv; 047 048 /** 049 * Constructs a new {@link FieldVisitor}. 050 * 051 * @param api the ASM API version implemented by this visitor. Must be one of {@link 052 * Opcodes#ASM4}, {@link Opcodes#ASM5}, {@link Opcodes#ASM6} or {@link Opcodes#ASM7}. 053 */ 054 public FieldVisitor(final int api) { 055 this(api, null); 056 } 057 058 /** 059 * Constructs a new {@link FieldVisitor}. 060 * 061 * @param api the ASM API version implemented by this visitor. Must be one of {@link 062 * Opcodes#ASM4}, {@link Opcodes#ASM5}, {@link Opcodes#ASM6} or {@link Opcodes#ASM7}. 063 * @param fieldVisitor the field visitor to which this visitor must delegate method calls. May be 064 * null. 065 */ 066 @SuppressWarnings("deprecation") 067 public FieldVisitor(final int api, final FieldVisitor fieldVisitor) { 068 if (api != Opcodes.ASM7 069 && api != Opcodes.ASM6 070 && api != Opcodes.ASM5 071 && api != Opcodes.ASM4 072 && api != Opcodes.ASM8_EXPERIMENTAL) { 073 throw new IllegalArgumentException("Unsupported api " + api); 074 } 075 // SPRING PATCH: no preview mode check for ASM 8 experimental 076 this.api = api; 077 this.fv = fieldVisitor; 078 } 079 080 /** 081 * Visits an annotation of the field. 082 * 083 * @param descriptor the class descriptor of the annotation class. 084 * @param visible {@literal true} if the annotation is visible at runtime. 085 * @return a visitor to visit the annotation values, or {@literal null} if this visitor is not 086 * interested in visiting this annotation. 087 */ 088 public AnnotationVisitor visitAnnotation(final String descriptor, final boolean visible) { 089 if (fv != null) { 090 return fv.visitAnnotation(descriptor, visible); 091 } 092 return null; 093 } 094 095 /** 096 * Visits an annotation on the type of the field. 097 * 098 * @param typeRef a reference to the annotated type. The sort of this type reference must be 099 * {@link TypeReference#FIELD}. See {@link TypeReference}. 100 * @param typePath the path to the annotated type argument, wildcard bound, array element type, or 101 * static inner type within 'typeRef'. May be {@literal null} if the annotation targets 102 * 'typeRef' as a whole. 103 * @param descriptor the class descriptor of the annotation class. 104 * @param visible {@literal true} if the annotation is visible at runtime. 105 * @return a visitor to visit the annotation values, or {@literal null} if this visitor is not 106 * interested in visiting this annotation. 107 */ 108 public AnnotationVisitor visitTypeAnnotation( 109 final int typeRef, final TypePath typePath, final String descriptor, final boolean visible) { 110 if (api < Opcodes.ASM5) { 111 throw new UnsupportedOperationException("This feature requires ASM5"); 112 } 113 if (fv != null) { 114 return fv.visitTypeAnnotation(typeRef, typePath, descriptor, visible); 115 } 116 return null; 117 } 118 119 /** 120 * Visits a non standard attribute of the field. 121 * 122 * @param attribute an attribute. 123 */ 124 public void visitAttribute(final Attribute attribute) { 125 if (fv != null) { 126 fv.visitAttribute(attribute); 127 } 128 } 129 130 /** 131 * Visits the end of the field. This method, which is the last one to be called, is used to inform 132 * the visitor that all the annotations and attributes of the field have been visited. 133 */ 134 public void visitEnd() { 135 if (fv != null) { 136 fv.visitEnd(); 137 } 138 } 139}