jdk8-mips64-public/langtools: src/share/classes/javax/lang/model/util/AbstractElementVisitor6.java@09f65aad4759 (annotated)

src/share/classes/javax/lang/model/util/AbstractElementVisitor6.java@09f65aad4759 (annotated)

src/share/classes/javax/lang/model/util/AbstractElementVisitor6.java

Wed, 23 Jan 2013 20:11:07 -0800

author: darcy
date: Wed, 23 Jan 2013 20:11:07 -0800
changeset 1522: 09f65aad4759
parent 1357: c75be5bc5283
child 2525: 2eb010b6cb22
permissions: -rw-r--r--

8006264: Add explanation of why default methods cannot be used in JDK 8 javax.lang.model
Reviewed-by: jjg

 /*
  * 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
  * or visit www.oracle.com if you need additional information or have any
  * questions.
  */
 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&trade; 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 Ah&eacute;
  *
  * @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);
     }
 }

Mercurial > jdk8-mips64-public > langtools / annotate

src/share/classes/javax/lang/model/util/AbstractElementVisitor6.java@09f65aad4759 (annotated)

src/share/classes/javax/lang/model/util/AbstractElementVisitor6.java