Mercurial > jdk8-mips64-public > langtools / file revision

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  * Copyright (c) 2005, 2013, 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

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 package javax.lang.model.util;

 import javax.annotation.processing.SupportedSourceVersion;

 import javax.lang.model.SourceVersion;

 import javax.lang.model.element.*;

 import static javax.lang.model.SourceVersion.*;

 /**

  * A skeletal visitor of program elements with default behavior

  * appropriate for the {@link SourceVersion#RELEASE_6 RELEASE_6}

  * source version.

  *

  * <p> <b>WARNING:</b> The {@code ElementVisitor} 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 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 call the {@link

  * #visitUnknown visitUnknown} method.  A new abstract element 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 the new visitor is introduced, all

  * or portions of this visitor may be deprecated.

  *

  * <p>Note that adding a default implementation of a new visit method

  * in a visitor class will occur instead of adding a <em>default

  * method</em> directly in the visitor interface since a Java SE 8

  * language feature cannot be used to this version of the API since

  * this version is required to be runnable on Java SE 7

  * implementations.  Future versions of the API that are only required

  * to run on Java SE 8 and later may take advantage of default methods

  * in this situation.

  *

  * @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 Ahé

  *

  * @see AbstractElementVisitor7

  * @see AbstractElementVisitor8

  * @since 1.6

  */

 @SupportedSourceVersion(RELEASE_6)

 public abstract class AbstractElementVisitor6<R, P> implements ElementVisitor<R, P> {

     /**

      * Constructor for concrete subclasses to call.

      */

     protected AbstractElementVisitor6(){}

     /**

      * Visits any program element as if by passing itself to that

      * element's {@link Element#accept accept} method.  The invocation

      * {@code v.visit(elem)} is equivalent to {@code elem.accept(v,

      * p)}.

      *

      * @param e  the element to visit

      * @param p  a visitor-specified parameter

      * @return a visitor-specified result

      */

     public final R visit(Element e, P p) {

         return e.accept(this, p);

     }

     /**

      * Visits any program element as if by passing itself to that

      * element's {@link Element#accept accept} method and passing

      * {@code null} for the additional parameter.  The invocation

      * {@code v.visit(elem)} is equivalent to {@code elem.accept(v,

      * null)}.

      *

      * @param e  the element to visit

      * @return a visitor-specified result

      */

     public final R visit(Element e) {

         return e.accept(this, null);

     }

     /**

      * {@inheritDoc}

      *

      * <p> The default implementation of this method in

      * {@code AbstractElementVisitor6} will always throw

      * {@code UnknownElementException}.

      * This behavior is not required of a subclass.

      *

      * @param e  the element to visit

      * @param p  a visitor-specified parameter

      * @return a visitor-specified result

      * @throws UnknownElementException

      *          a visitor implementation may optionally throw this exception

      */

     public R visitUnknown(Element e, P p) {

         throw new UnknownElementException(e, p);

     }

 }