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ProGuardCORE is a free library to read, analyze, modify, and write Java class files.

There is a newer version: 9.1.6

/*
 * ProGuardCORE -- library to process Java bytecode.
 *
 * Copyright (c) 2002-2020 Guardsquare NV
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package proguard.classfile.attribute.annotation;

import proguard.classfile.*;
import proguard.classfile.attribute.annotation.visitor.ElementValueVisitor;
import proguard.classfile.visitor.MemberVisitor;
import proguard.util.SimpleProcessable;

/**
 * This abstract class represents an element value that is attached to an annotation or an
 * annotation default. Specific types of element values are subclassed from it.
 *
 * @author Eric Lafortune
 */
public abstract class ElementValue extends SimpleProcessable {
  public static final char TAG_STRING_CONSTANT = 's';
  public static final char TAG_ENUM_CONSTANT = 'e';
  public static final char TAG_CLASS = 'c';
  public static final char TAG_ANNOTATION = '@';
  public static final char TAG_ARRAY = '[';

  /**
   * An extra field for the optional element name. It is used in element value pairs of annotations.
   * Otherwise, it is 0.
   */
  public int u2elementNameIndex;

  /**
   * An extra field pointing to the referenced Clazz object, if applicable. This field
   * is typically filled out by the {@link proguard.classfile.util.ClassReferenceInitializer}
   * .
   */
  public Clazz referencedClass;

  /**
   * An extra field pointing to the referenced Method object, if applicable. This field
   * is typically filled out by the {@link proguard.classfile.util.ClassReferenceInitializer}
   * .
   */
  public Method referencedMethod;

  /** Creates an uninitialized ElementValue. */
  protected ElementValue() {}

  /** Creates an initialized ElementValue. */
  protected ElementValue(int u2elementNameIndex) {
    this.u2elementNameIndex = u2elementNameIndex;
  }

  /** Returns the element name. */
  public String getMethodName(Clazz clazz) {
    return clazz.getString(u2elementNameIndex);
  }

  // Abstract methods to be implemented by extensions.

  /** Returns the tag of this element value. */
  public abstract char getTag();

  /** Accepts the given visitor. */
  public abstract void accept(
      Clazz clazz, Annotation annotation, ElementValueVisitor elementValueVisitor);

  /** Applies the given visitor to the referenced method. */
  public void referencedMethodAccept(MemberVisitor memberVisitor) {
    if (referencedMethod != null) {
      referencedMethod.accept(referencedClass, memberVisitor);
    }
  }
}