content: /*
   * Copyright (c) 2005, 2020, Oracle and/or its affiliates. All rights reserved.
   * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   *
   * This code is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License version 2 only, as
   * published by the Free Software Foundation.  Oracle designates this
   * particular file as subject to the "Classpath" exception as provided
   * by Oracle in the LICENSE file that accompanied this code.
   *
   * This code is distributed in the hope that it will be useful, but WITHOUT
   * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
   * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
   * version 2 for more details (a copy is included in the LICENSE file that
   * accompanied this code).
   *
   * You should have received a copy of the GNU General Public License version
   * 2 along with this work; if not, write to the Free Software Foundation,
   * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
   *
   * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
   * or visit www.oracle.com if you need additional information or have any
   * questions.
   */
  
  package jdkx.lang.model.util;
  
  import jdkx.annotation.processing.SupportedSourceVersion;
  import jdkx.lang.model.type.*;
  
  import static jdkx.lang.model.SourceVersion.*;
  
  /**
   * A skeletal visitor of types with default behavior appropriate for
   * the {@link jdkx.lang.model.SourceVersion#RELEASE_6 RELEASE_6}
   * source version.
   *
   * @apiNote
   * <p id=note_for_subclasses><strong>WARNING:</strong> The {@code
   * TypeVisitor} interface implemented by this class may have methods
   * added to it in the future to accommodate new, currently unknown,
   * language structures added to future versions of the Java
   * programming language.  Therefore, methods whose names begin with
   * {@code "visit"} may be added to this class in the future; to avoid
   * incompatibilities, classes and subclasses which extend this class
   * should not declare any instance methods with names beginning with
   * {@code "visit"}.
   *
   * <p>When such a new visit method is added, the default
   * implementation in this class will be to directly or indirectly call
   * the {@link #visitUnknown visitUnknown} method.  A new abstract type
   * visitor class will also be introduced to correspond to the new
   * language level; this visitor will have different default behavior
   * for the visit method in question.  When a new visitor is
   * introduced, portions of this visitor class may be deprecated,
   * including its constructors.
   *
   * @param <R> the return type of this visitor's methods.  Use {@link
   *            Void} for visitors that do not need to return results.
   * @param <P> the type of the additional parameter to this visitor's
   *            methods.  Use {@code Void} for visitors that do not need an
   *            additional parameter.
   *
   * @author Joseph D. Darcy
   * @author Scott Seligman
   * @author Peter von der Ah&eacute;
   *
   * @see AbstractTypeVisitor7
   * @see AbstractTypeVisitor8
   * @see AbstractTypeVisitor9
   * @see AbstractTypeVisitor14
   * @since 1.6
   */
  @SupportedSourceVersion(RELEASE_6)
  public abstract class AbstractTypeVisitor6<R, P> implements TypeVisitor<R, P> {
      /**
       * Constructor for concrete subclasses to call.
       * @deprecated Release 6 is obsolete; update to a visitor for a newer
       * release level.
       */
      @Deprecated(since="9")
      protected AbstractTypeVisitor6() {}
  
      /**
       * Visits any type mirror as if by passing itself to that type
       * mirror's {@link TypeMirror#accept accept} method.  The
       * invocation {@code v.visit(t, p)} is equivalent to {@code
       * t.accept(v, p)}.
       *
       * @param t  the type to visit
       * @param p  a visitor-specified parameter
       * @return a visitor-specified result
       */
      public final R visit(TypeMirror t, P p) {
          return t.accept(this, p);
      }
  
      /**
       * Visits any type mirror as if by passing itself to that type
       * mirror's {@link TypeMirror#accept accept} method and passing
       * {@code null} for the additional parameter.  The invocation
       * {@code v.visit(t)} is equivalent to {@code t.accept(v, null)}.
       *
       * @param t  the type to visit
       * @return a visitor-specified result
       */
      public final R visit(TypeMirror t) {
          return t.accept(this, null);
      }
  
      /**
       * {@inheritDoc}
       *
       * @implSpec Visits a {@code UnionType} element by calling {@code
       * visitUnknown}.
       *
       * @param t  {@inheritDoc}
       * @param p  {@inheritDoc}
       * @return the result of {@code visitUnknown}
       *
       * @since 1.7
       */
      public R visitUnion(UnionType t, P p) {
          return visitUnknown(t, p);
      }
  
      /**
       * {@inheritDoc}
       *
       * @implSpec Visits an {@code IntersectionType} element by calling {@code
       * visitUnknown}.
       *
       * @param t  {@inheritDoc}
       * @param p  {@inheritDoc}
       * @return the result of {@code visitUnknown}
       *
       * @since 1.8
       */
      @Override
      public R visitIntersection(IntersectionType t, P p) {
          return visitUnknown(t, p);
      }
  
      /**
       * {@inheritDoc}
       *
       * @implSpec The default implementation of this method in {@code
       * AbstractTypeVisitor6} will always throw {@code
       * new UnknownTypeException(t, p)}.  This behavior is not required of a
       * subclass.
       *
       * @param t  {@inheritDoc}
       * @param p  {@inheritDoc}
       * @return a visitor-specified result
       * @throws UnknownTypeException
       *  a visitor implementation may optionally throw this exception
       */
      @Override
      public R visitUnknown(TypeMirror t, P p) {
          throw new UnknownTypeException(t, p);
      }
  }
  