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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.visitor;

import proguard.classfile.*;

/**
 * This {@link ClassVisitor} lets a given {@link ClassVisitor} travel to the first concrete
 * subclasses down in its hierarchy of abstract classes and concrete classes.
 *
 * @author Eric Lafortune
 */
public class ConcreteClassDownTraveler implements ClassVisitor {
  private final ClassVisitor classVisitor;

  /**
   * Creates a new ConcreteClassDownTraveler.
   *
   * @param classVisitor the ClassVisitor to which visits will be delegated.
   */
  public ConcreteClassDownTraveler(ClassVisitor classVisitor) {
    this.classVisitor = classVisitor;
  }

  // Implementations for ClassVisitor.

  @Override
  public void visitAnyClass(Clazz clazz) {
    throw new UnsupportedOperationException(
        this.getClass().getName() + " does not support " + clazz.getClass().getName());
  }

  @Override
  public void visitProgramClass(ProgramClass programClass) {
    // Is this an abstract class or an interface?
    if ((programClass.getAccessFlags() & (AccessConstants.INTERFACE | AccessConstants.ABSTRACT))
        != 0) {
      // Travel down the hierarchy.
      int subClassCount = programClass.subClassCount;
      Clazz[] subClasses = programClass.subClasses;
      for (int index = 0; index < subClassCount; index++) {
        subClasses[index].accept(this);
      }
    } else {
      // Visit the class. Don't descend any further.
      programClass.accept(classVisitor);
    }
  }

  @Override
  public void visitLibraryClass(LibraryClass libraryClass) {
    // Is this an abstract class or interface?
    if ((libraryClass.getAccessFlags() & (AccessConstants.INTERFACE | AccessConstants.ABSTRACT))
        != 0) {
      // Travel down the hierarchy.
      int subClassCount = libraryClass.subClassCount;
      Clazz[] subClasses = libraryClass.subClasses;
      for (int index = 0; index < subClassCount; index++) {
        subClasses[index].accept(this);
      }
    } else {
      // Visit the class. Don't descend any further.
      libraryClass.accept(classVisitor);
    }
  }
}