ASM: a very small and fast Java bytecode manipulation framework
Copyright (c) 2000-2011 INRIA, France Telecom
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/***
 * ASM: a very small and fast Java bytecode manipulation framework
 * Copyright (c) 2000-2011 INRIA, France Telecom
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the copyright holders nor the names of its
 *    contributors may be used to endorse or promote products derived from
 *    this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
 * THE POSSIBILITY OF SUCH DAMAGE.
 */
package org.objectweb.asm;

A visitor to visit a Java field. The methods of this class must be called in
the following order: ( visitAnnotation |
visitTypeAnnotation | visitAttribute )* visitEnd.
Author:
Eric Bruneton/**
 * A visitor to visit a Java field. The methods of this class must be called in
 * the following order: ( <tt>visitAnnotation</tt> |
 * <tt>visitTypeAnnotation</tt> | <tt>visitAttribute</tt> )* <tt>visitEnd</tt>.
 * 
 * @author Eric Bruneton
 */
public abstract class FieldVisitor {

    
The ASM API version implemented by this visitor. The value of this field must be one of Opcodes.ASM4 or Opcodes.ASM5. /**
     * The ASM API version implemented by this visitor. The value of this field
     * must be one of {@link Opcodes#ASM4} or {@link Opcodes#ASM5}.
     */
    protected final int api;

    
The field visitor to which this visitor must delegate method calls. May
be null.
/**
     * The field visitor to which this visitor must delegate method calls. May
     * be null.
     */
    protected FieldVisitor fv;

    
Constructs a new FieldVisitor. 
Params:
api –  the ASM API version implemented by this visitor. Must be one of Opcodes.ASM4 or Opcodes.ASM5./**
     * Constructs a new {@link FieldVisitor}.
     * 
     * @param api
     *            the ASM API version implemented by this visitor. Must be one
     *            of {@link Opcodes#ASM4} or {@link Opcodes#ASM5}.
     */
    public FieldVisitor(final int api) {
        this(api, null);
    }

    
Constructs a new FieldVisitor. 
Params:
api –  the ASM API version implemented by this visitor. Must be one of Opcodes.ASM4 or Opcodes.ASM5.
fv – 
           the field visitor to which this visitor must delegate method
           calls. May be null./**
     * Constructs a new {@link FieldVisitor}.
     * 
     * @param api
     *            the ASM API version implemented by this visitor. Must be one
     *            of {@link Opcodes#ASM4} or {@link Opcodes#ASM5}.
     * @param fv
     *            the field visitor to which this visitor must delegate method
     *            calls. May be null.
     */
    public FieldVisitor(final int api, final FieldVisitor fv) {
        if (api != Opcodes.ASM4 && api != Opcodes.ASM5) {
            throw new IllegalArgumentException();
        }
        this.api = api;
        this.fv = fv;
    }

    
Visits an annotation of the field.
Params:
desc – 
           the class descriptor of the annotation class.
visible – 
           true if the annotation is visible at runtime.
Returns:
a visitor to visit the annotation values, or null if
        this visitor is not interested in visiting this annotation./**
     * Visits an annotation of the field.
     * 
     * @param desc
     *            the class descriptor of the annotation class.
     * @param visible
     *            <tt>true</tt> if the annotation is visible at runtime.
     * @return a visitor to visit the annotation values, or <tt>null</tt> if
     *         this visitor is not interested in visiting this annotation.
     */
    public AnnotationVisitor visitAnnotation(String desc, boolean visible) {
        if (fv != null) {
            return fv.visitAnnotation(desc, visible);
        }
        return null;
    }

    
Visits an annotation on the type of the field.
Params:
typeRef –  a reference to the annotated type. The sort of this type reference must be FIELD. See TypeReference.
typePath – 
           the path to the annotated type argument, wildcard bound, array
           element type, or static inner type within 'typeRef'. May be
           null if the annotation targets 'typeRef' as a whole.
desc – 
           the class descriptor of the annotation class.
visible – 
           true if the annotation is visible at runtime.
Returns:
a visitor to visit the annotation values, or null if
        this visitor is not interested in visiting this annotation./**
     * Visits an annotation on the type of the field.
     * 
     * @param typeRef
     *            a reference to the annotated type. The sort of this type
     *            reference must be {@link TypeReference#FIELD FIELD}. See
     *            {@link TypeReference}.
     * @param typePath
     *            the path to the annotated type argument, wildcard bound, array
     *            element type, or static inner type within 'typeRef'. May be
     *            <tt>null</tt> if the annotation targets 'typeRef' as a whole.
     * @param desc
     *            the class descriptor of the annotation class.
     * @param visible
     *            <tt>true</tt> if the annotation is visible at runtime.
     * @return a visitor to visit the annotation values, or <tt>null</tt> if
     *         this visitor is not interested in visiting this annotation.
     */
    public AnnotationVisitor visitTypeAnnotation(int typeRef,
            TypePath typePath, String desc, boolean visible) {
        if (api < Opcodes.ASM5) {
            throw new RuntimeException();
        }
        if (fv != null) {
            return fv.visitTypeAnnotation(typeRef, typePath, desc, visible);
        }
        return null;
    }

    
Visits a non standard attribute of the field.
Params:
attr – 
           an attribute./**
     * Visits a non standard attribute of the field.
     * 
     * @param attr
     *            an attribute.
     */
    public void visitAttribute(Attribute attr) {
        if (fv != null) {
            fv.visitAttribute(attr);
        }
    }

    
Visits the end of the field. This method, which is the last one to be
called, is used to inform the visitor that all the annotations and
attributes of the field have been visited.
/**
     * Visits the end of the field. This method, which is the last one to be
     * called, is used to inform the visitor that all the annotations and
     * attributes of the field have been visited.
     */
    public void visitEnd() {
        if (fv != null) {
            fv.visitEnd();
        }
    }
}