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/*
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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 jdk.internal.org.objectweb.asm;

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

    /**
      * The ASM API version implemented by this visitor. The value of this field must be one of the
      * {@code ASM}<i>x</i> values in {@link Opcodes}.
      */
    protected final int api;

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

    /**
      * Constructs a new {@link FieldVisitor}.
      *
      * @param api the ASM API version implemented by this visitor. Must be one of the {@code
      *     ASM}<i>x</i> values in {@link Opcodes}.
      */
    protected FieldVisitor(final int api) {
        this(api, null);
    }

    /**
      * Constructs a new {@link FieldVisitor}.
      *
      * @param api the ASM API version implemented by this visitor. Must be one of the {@code
      *     ASM}<i>x</i> values in {@link Opcodes}.
      * @param fieldVisitor the field visitor to which this visitor must delegate method calls. May be
      *     null.
      */
    protected FieldVisitor(final int api, final FieldVisitor fieldVisitor) {
        if (api != Opcodes.ASM9
                && api != Opcodes.ASM8
                && api != Opcodes.ASM7
                && api != Opcodes.ASM6
                && api != Opcodes.ASM5
                && api != Opcodes.ASM4) {
            throw new IllegalArgumentException("Unsupported api " + api);
        }
        this.api = api;
        this.fv = fieldVisitor;
    }

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

    /**
      * 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}. 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 {@literal null} if the annotation targets
      *     'typeRef' as a whole.
      * @param descriptor the class descriptor of the annotation class.
      * @param visible {@literal true} if the annotation is visible at runtime.
      * @return a visitor to visit the annotation values, or {@literal null} if this visitor is not
      *     interested in visiting this annotation.
      */
    public AnnotationVisitor visitTypeAnnotation(
            final int typeRef, final TypePath typePath, final String descriptor, final boolean visible) {
        if (api < Opcodes.ASM5) {
            throw new UnsupportedOperationException("This feature requires ASM5");
        }
        if (fv != null) {
            return fv.visitTypeAnnotation(typeRef, typePath, descriptor, visible);
        }
        return null;
    }

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

    /**
      * 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();
        }
    }
}

