1 // ASM: a very small and fast Java bytecode manipulation framework 2 // Copyright (c) 2000-2011 INRIA, France Telecom 3 // All rights reserved. 4 // 5 // Redistribution and use in source and binary forms, with or without 6 // modification, are permitted provided that the following conditions 7 // are met: 8 // 1. Redistributions of source code must retain the above copyright 9 // notice, this list of conditions and the following disclaimer. 10 // 2. Redistributions in binary form must reproduce the above copyright 11 // notice, this list of conditions and the following disclaimer in the 12 // documentation and/or other materials provided with the distribution. 13 // 3. Neither the name of the copyright holders nor the names of its 14 // contributors may be used to endorse or promote products derived from 15 // this software without specific prior written permission. 16 // 17 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 18 // AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 // IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 // ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE 21 // LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 22 // CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 23 // SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 24 // INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 25 // CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 26 // ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF 27 // THE POSSIBILITY OF SUCH DAMAGE. 28 package org.objectweb.asm; 29 30 /** 31 * A visitor to visit a Java field. The methods of this class must be called in the following order: 32 * ( {@code visitAnnotation} | {@code visitTypeAnnotation} | {@code visitAttribute} )* {@code 33 * visitEnd}. 34 * 35 * @author Eric Bruneton 36 */ 37 public abstract class FieldVisitor { 38 39 /** 40 * The ASM API version implemented by this visitor. The value of this field must be one of the 41 * {@code ASM}<i>x</i> values in {@link Opcodes}. 42 */ 43 protected final int api; 44 45 /** The field visitor to which this visitor must delegate method calls. May be {@literal null}. */ 46 protected FieldVisitor fv; 47 48 /** 49 * Constructs a new {@link FieldVisitor}. 50 * 51 * @param api the ASM API version implemented by this visitor. Must be one of the {@code 52 * ASM}<i>x</i> values in {@link Opcodes}. 53 */ FieldVisitor(final int api)54 protected FieldVisitor(final int api) { 55 this(api, null); 56 } 57 58 /** 59 * Constructs a new {@link FieldVisitor}. 60 * 61 * @param api the ASM API version implemented by this visitor. Must be one of the {@code 62 * ASM}<i>x</i> values in {@link Opcodes}. 63 * @param fieldVisitor the field visitor to which this visitor must delegate method calls. May be 64 * null. 65 */ FieldVisitor(final int api, final FieldVisitor fieldVisitor)66 protected FieldVisitor(final int api, final FieldVisitor fieldVisitor) { 67 if (api != Opcodes.ASM9 68 && api != Opcodes.ASM8 69 && api != Opcodes.ASM7 70 && api != Opcodes.ASM6 71 && api != Opcodes.ASM5 72 && api != Opcodes.ASM4 73 && api != Opcodes.ASM10_EXPERIMENTAL) { 74 throw new IllegalArgumentException("Unsupported api " + api); 75 } 76 if (api == Opcodes.ASM10_EXPERIMENTAL) { 77 Constants.checkAsmExperimental(this); 78 } 79 this.api = api; 80 this.fv = fieldVisitor; 81 } 82 83 /** 84 * The field visitor to which this visitor must delegate method calls. May be {@literal null}. 85 * 86 * @return the field visitor to which this visitor must delegate method calls, or {@literal null}. 87 */ getDelegate()88 public FieldVisitor getDelegate() { 89 return fv; 90 } 91 92 /** 93 * Visits an annotation of the field. 94 * 95 * @param descriptor the class descriptor of the annotation class. 96 * @param visible {@literal true} if the annotation is visible at runtime. 97 * @return a visitor to visit the annotation values, or {@literal null} if this visitor is not 98 * interested in visiting this annotation. 99 */ visitAnnotation(final String descriptor, final boolean visible)100 public AnnotationVisitor visitAnnotation(final String descriptor, final boolean visible) { 101 if (fv != null) { 102 return fv.visitAnnotation(descriptor, visible); 103 } 104 return null; 105 } 106 107 /** 108 * Visits an annotation on the type of the field. 109 * 110 * @param typeRef a reference to the annotated type. The sort of this type reference must be 111 * {@link TypeReference#FIELD}. See {@link TypeReference}. 112 * @param typePath the path to the annotated type argument, wildcard bound, array element type, or 113 * static inner type within 'typeRef'. May be {@literal null} if the annotation targets 114 * 'typeRef' as a whole. 115 * @param descriptor the class descriptor of the annotation class. 116 * @param visible {@literal true} if the annotation is visible at runtime. 117 * @return a visitor to visit the annotation values, or {@literal null} if this visitor is not 118 * interested in visiting this annotation. 119 */ visitTypeAnnotation( final int typeRef, final TypePath typePath, final String descriptor, final boolean visible)120 public AnnotationVisitor visitTypeAnnotation( 121 final int typeRef, final TypePath typePath, final String descriptor, final boolean visible) { 122 if (api < Opcodes.ASM5) { 123 throw new UnsupportedOperationException("This feature requires ASM5"); 124 } 125 if (fv != null) { 126 return fv.visitTypeAnnotation(typeRef, typePath, descriptor, visible); 127 } 128 return null; 129 } 130 131 /** 132 * Visits a non standard attribute of the field. 133 * 134 * @param attribute an attribute. 135 */ visitAttribute(final Attribute attribute)136 public void visitAttribute(final Attribute attribute) { 137 if (fv != null) { 138 fv.visitAttribute(attribute); 139 } 140 } 141 142 /** 143 * Visits the end of the field. This method, which is the last one to be called, is used to inform 144 * the visitor that all the annotations and attributes of the field have been visited. 145 */ visitEnd()146 public void visitEnd() { 147 if (fv != null) { 148 fv.visitEnd(); 149 } 150 } 151 } 152