// ASM: a very small and fast Java bytecode manipulation framework
// Copyright (c) 2000-2011 INRIA, France Telecom
// All rights reserved.
//
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// modification, are permitted provided that the following conditions
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//    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
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//    this software without specific prior written permission.
//
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package org.objectweb.asm;

/**
 * A visitor to visit a Java module. The methods of this class must be called in the following
 * order: ( {@code visitMainClass} | ( {@code visitPackage} | {@code visitRequire} | {@code
 * visitExport} | {@code visitOpen} | {@code visitUse} | {@code visitProvide} )* ) {@code visitEnd}.
 *
 * @author Remi Forax
 * @author Eric Bruneton
 */
public abstract class ModuleVisitor {
  /**
   * The ASM API version implemented by this visitor. The value of this field must be one of {@link
   * Opcodes#ASM6} or {@link Opcodes#ASM7}.
   */
  protected final int api;

  /**
   * The module visitor to which this visitor must delegate method calls. May be {@literal null}.
   */
  protected ModuleVisitor mv;

  /**
   * Constructs a new {@link ModuleVisitor}.
   *
   * @param api the ASM API version implemented by this visitor. Must be one of {@link Opcodes#ASM6}
   *     or {@link Opcodes#ASM7}.
   */
  protected ModuleVisitor(final int api) {
    this(api, null);
  }

  /**
   * Constructs a new {@link ModuleVisitor}.
   *
   * @param api the ASM API version implemented by this visitor. Must be one of {@link Opcodes#ASM6}
   *     or {@link Opcodes#ASM7}.
   * @param moduleVisitor the module visitor to which this visitor must delegate method calls. May
   *     be null.
   */
  protected ModuleVisitor(final int api, final ModuleVisitor moduleVisitor) {
    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.mv = moduleVisitor;
  }

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

  /**
   * Visit the main class of the current module.
   *
   * @param mainClass the internal name of the main class of the current module (see {@link
   *     Type#getInternalName()}).
   */
  public void visitMainClass(final String mainClass) {
    if (mv != null) {
      mv.visitMainClass(mainClass);
    }
  }

  /**
   * Visit a package of the current module.
   *
   * @param packaze the internal name of a package (see {@link Type#getInternalName()}).
   */
  public void visitPackage(final String packaze) {
    if (mv != null) {
      mv.visitPackage(packaze);
    }
  }

  /**
   * Visits a dependence of the current module.
   *
   * @param module the fully qualified name (using dots) of the dependence.
   * @param access the access flag of the dependence among {@code ACC_TRANSITIVE}, {@code
   *     ACC_STATIC_PHASE}, {@code ACC_SYNTHETIC} and {@code ACC_MANDATED}.
   * @param version the module version at compile time, or {@literal null}.
   */
  public void visitRequire(final String module, final int access, final String version) {
    if (mv != null) {
      mv.visitRequire(module, access, version);
    }
  }

  /**
   * Visit an exported package of the current module.
   *
   * @param packaze the internal name of the exported package (see {@link Type#getInternalName()}).
   * @param access the access flag of the exported package, valid values are among {@code
   *     ACC_SYNTHETIC} and {@code ACC_MANDATED}.
   * @param modules the fully qualified names (using dots) of the modules that can access the public
   *     classes of the exported package, or {@literal null}.
   */
  public void visitExport(final String packaze, final int access, final String... modules) {
    if (mv != null) {
      mv.visitExport(packaze, access, modules);
    }
  }

  /**
   * Visit an open package of the current module.
   *
   * @param packaze the internal name of the opened package (see {@link Type#getInternalName()}).
   * @param access the access flag of the opened package, valid values are among {@code
   *     ACC_SYNTHETIC} and {@code ACC_MANDATED}.
   * @param modules the fully qualified names (using dots) of the modules that can use deep
   *     reflection to the classes of the open package, or {@literal null}.
   */
  public void visitOpen(final String packaze, final int access, final String... modules) {
    if (mv != null) {
      mv.visitOpen(packaze, access, modules);
    }
  }

  /**
   * Visit a service used by the current module. The name must be the internal name of an interface
   * or a class.
   *
   * @param service the internal name of the service (see {@link Type#getInternalName()}).
   */
  public void visitUse(final String service) {
    if (mv != null) {
      mv.visitUse(service);
    }
  }

  /**
   * Visit an implementation of a service.
   *
   * @param service the internal name of the service (see {@link Type#getInternalName()}).
   * @param providers the internal names (see {@link Type#getInternalName()}) of the implementations
   *     of the service (there is at least one provider).
   */
  public void visitProvide(final String service, final String... providers) {
    if (mv != null) {
      mv.visitProvide(service, providers);
    }
  }

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