AnnotationVisitor.java

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 * published by the Free Software Foundation.  Oracle designates this
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/*
 * This file is available under and governed by the GNU General Public
 * License version 2 only, as published by the Free Software Foundation.
 * However, the following notice accompanied the original version of this
 * file:
 *
 * 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 annotation. The methods of this class must be called in the following
 * order: ( {@code visit} | {@code visitEnum} | {@code visitAnnotation} | {@code visitArray} )*
 * {@code visitEnd}.
 *
 * @author Eric Bruneton
 * @author Eugene Kuleshov
 */
public abstract class AnnotationVisitor {

    /**
      * 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 annotation visitor to which this visitor must delegate method calls. May be {@literal
      * null}.
      */
    protected AnnotationVisitor av;

    /**
      * Constructs a new {@link AnnotationVisitor}.
      *
      * @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 AnnotationVisitor(final int api) {
        this(api, null);
    }

    /**
      * Constructs a new {@link AnnotationVisitor}.
      *
      * @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 annotationVisitor the annotation visitor to which this visitor must delegate method
      *     calls. May be {@literal null}.
      */
    protected AnnotationVisitor(final int api, final AnnotationVisitor annotationVisitor) {
        if (api != Opcodes.ASM9
                && api != Opcodes.ASM8
                && api != Opcodes.ASM7
                && api != Opcodes.ASM6
                && api != Opcodes.ASM5
                && api != Opcodes.ASM4
                && api != Opcodes.ASM10_EXPERIMENTAL) {
            throw new IllegalArgumentException("Unsupported api " + api);
        }
        if (api == Opcodes.ASM10_EXPERIMENTAL) {
            Constants.checkAsmExperimental(this);
        }
        this.api = api;
        this.av = annotationVisitor;
    }

    /**
      * The annotation visitor to which this visitor must delegate method calls. May be {@literal
      * null}.
      *
      * @return the annotation visitor to which this visitor must delegate method calls, or {@literal
      *     null}.
      */
    public AnnotationVisitor getDelegate() {
        return av;
    }

    /**
      * Visits a primitive value of the annotation.
      *
      * @param name the value name.
      * @param value the actual value, whose type must be {@link Byte}, {@link Boolean}, {@link
      *     Character}, {@link Short}, {@link Integer} , {@link Long}, {@link Float}, {@link Double},
      *     {@link String} or {@link Type} of {@link Type#OBJECT} or {@link Type#ARRAY} sort. This
      *     value can also be an array of byte, boolean, short, char, int, long, float or double values
      *     (this is equivalent to using {@link #visitArray} and visiting each array element in turn,
      *     but is more convenient).
      */
    public void visit(final String name, final Object value) {
        if (av != null) {
            av.visit(name, value);
        }
    }

    /**
      * Visits an enumeration value of the annotation.
      *
      * @param name the value name.
      * @param descriptor the class descriptor of the enumeration class.
      * @param value the actual enumeration value.
      */
    public void visitEnum(final String name, final String descriptor, final String value) {
        if (av != null) {
            av.visitEnum(name, descriptor, value);
        }
    }

    /**
      * Visits a nested annotation value of the annotation.
      *
      * @param name the value name.
      * @param descriptor the class descriptor of the nested annotation class.
      * @return a visitor to visit the actual nested annotation value, or {@literal null} if this
      *     visitor is not interested in visiting this nested annotation. <i>The nested annotation
      *     value must be fully visited before calling other methods on this annotation visitor</i>.
      */
    public AnnotationVisitor visitAnnotation(final String name, final String descriptor) {
        if (av != null) {
            return av.visitAnnotation(name, descriptor);
        }
        return null;
    }

    /**
      * Visits an array value of the annotation. Note that arrays of primitive values (such as byte,
      * boolean, short, char, int, long, float or double) can be passed as value to {@link #visit
      * visit}. This is what {@link ClassReader} does for non empty arrays of primitive values.
      *
      * @param name the value name.
      * @return a visitor to visit the actual array value elements, or {@literal null} if this visitor
      *     is not interested in visiting these values. The 'name' parameters passed to the methods of
      *     this visitor are ignored. <i>All the array values must be visited before calling other
      *     methods on this annotation visitor</i>.
      */
    public AnnotationVisitor visitArray(final String name) {
        if (av != null) {
            return av.visitArray(name);
        }
        return null;
    }

    /** Visits the end of the annotation. */
    public void visitEnd() {
        if (av != null) {
            av.visitEnd();
        }
    }
}