jdk8-mips64-public/langtools: src/share/classes/javax/lang/model/util/ElementKindVisitor6.java@09f65aad4759 (annotated)

src/share/classes/javax/lang/model/util/ElementKindVisitor6.java@09f65aad4759 (annotated)

src/share/classes/javax/lang/model/util/ElementKindVisitor6.java

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

author: darcy
date: Wed, 23 Jan 2013 20:11:07 -0800
changeset 1522: 09f65aad4759
parent 1054: 111bbf1ad913
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.lang.model.element.*;
 import static javax.lang.model.element.ElementKind.*;
 import javax.annotation.processing.SupportedSourceVersion;
 import static javax.lang.model.SourceVersion.*;
 import javax.lang.model.SourceVersion;
 /**
  * A visitor of program elements based on their {@linkplain
  * ElementKind kind} with default behavior appropriate for the {@link
  * SourceVersion#RELEASE_6 RELEASE_6} source version.  For {@linkplain
  * Element elements} <tt><i>XYZ</i></tt> that may have more than one
  * kind, the <tt>visit<i>XYZ</i></tt> methods in this class delegate
  * to the <tt>visit<i>XYZKind</i></tt> method corresponding to the
  * first argument's kind.  The <tt>visit<i>XYZKind</i></tt> methods
  * call {@link #defaultAction defaultAction}, passing their arguments
  * to {@code defaultAction}'s corresponding parameters.
  *
  * <p> Methods in this class may be overridden subject to their
  * general contract.  Note that annotating methods in concrete
  * subclasses with {@link java.lang.Override @Override} will help
  * ensure that methods are overridden as intended.
  *
  * <p> <b>WARNING:</b> The {@code ElementVisitor} interface
  * implemented by this class may have methods added to it or the
  * {@code ElementKind} {@code enum} used in this case may have
  * constants 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 kind
  * 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 ElementKindVisitor7
  * @see ElementKindVisitor8
  * @since 1.6
  */
 @SupportedSourceVersion(RELEASE_6)
 public class ElementKindVisitor6<R, P>
                   extends SimpleElementVisitor6<R, P> {
     /**
      * Constructor for concrete subclasses; uses {@code null} for the
      * default value.
      */
     protected ElementKindVisitor6() {
         super(null);
     }
     /**
      * Constructor for concrete subclasses; uses the argument for the
      * default value.
      *
      * @param defaultValue the value to assign to {@link #DEFAULT_VALUE}
      */
     protected ElementKindVisitor6(R defaultValue) {
         super(defaultValue);
     }
     /**
      * {@inheritDoc}
      *
      * The element argument has kind {@code PACKAGE}.
      *
      * @param e {@inheritDoc}
      * @param p {@inheritDoc}
      * @return  {@inheritDoc}
      */
     @Override
     public R visitPackage(PackageElement e, P p) {
         assert e.getKind() == PACKAGE: "Bad kind on PackageElement";
         return defaultAction(e, p);
     }
     /**
      * Visits a type element, dispatching to the visit method for the
      * specific {@linkplain ElementKind kind} of type, {@code
      * ANNOTATION_TYPE}, {@code CLASS}, {@code ENUM}, or {@code
      * INTERFACE}.
      *
      * @param e {@inheritDoc}
      * @param p {@inheritDoc}
      * @return  the result of the kind-specific visit method
      */
     @Override
     public R visitType(TypeElement e, P p) {
         ElementKind k = e.getKind();
         switch(k) {
         case ANNOTATION_TYPE:
             return visitTypeAsAnnotationType(e, p);
         case CLASS:
             return visitTypeAsClass(e, p);
         case ENUM:
             return visitTypeAsEnum(e, p);
         case INTERFACE:
             return visitTypeAsInterface(e, p);
         default:
             throw new AssertionError("Bad kind " + k + " for TypeElement" + e);
         }
     }
     /**
      * Visits an {@code ANNOTATION_TYPE} type element by calling
      * {@code defaultAction}.
      *
      * @param e the element to visit
      * @param p a visitor-specified parameter
      * @return  the result of {@code defaultAction}
      */
     public R visitTypeAsAnnotationType(TypeElement e, P p) {
         return defaultAction(e, p);
     }
     /**
      * Visits a {@code CLASS} type element by calling {@code
      * defaultAction}.
      *
      * @param e the element to visit
      * @param p a visitor-specified parameter
      * @return  the result of {@code defaultAction}
      */
     public R visitTypeAsClass(TypeElement e, P p) {
         return defaultAction(e, p);
     }
     /**
      * Visits an {@code ENUM} type element by calling {@code
      * defaultAction}.
      *
      * @param e the element to visit
      * @param p a visitor-specified parameter
      * @return  the result of {@code defaultAction}
      */
     public R visitTypeAsEnum(TypeElement e, P p) {
         return defaultAction(e, p);
     }
     /**
      * Visits an {@code INTERFACE} type element by calling {@code
      * defaultAction}.
      *.
      * @param e the element to visit
      * @param p a visitor-specified parameter
      * @return  the result of {@code defaultAction}
      */
     public R visitTypeAsInterface(TypeElement e, P p) {
         return defaultAction(e, p);
     }
     /**
      * Visits a variable element, dispatching to the visit method for
      * the specific {@linkplain ElementKind kind} of variable, {@code
      * ENUM_CONSTANT}, {@code EXCEPTION_PARAMETER}, {@code FIELD},
      * {@code LOCAL_VARIABLE}, {@code PARAMETER}, or {@code RESOURCE_VARIABLE}.
      *
      * @param e {@inheritDoc}
      * @param p {@inheritDoc}
      * @return  the result of the kind-specific visit method
      */
     @Override
     public R visitVariable(VariableElement e, P p) {
         ElementKind k = e.getKind();
         switch(k) {
         case ENUM_CONSTANT:
             return visitVariableAsEnumConstant(e, p);
         case EXCEPTION_PARAMETER:
             return visitVariableAsExceptionParameter(e, p);
         case FIELD:
             return visitVariableAsField(e, p);
         case LOCAL_VARIABLE:
             return visitVariableAsLocalVariable(e, p);
         case PARAMETER:
             return visitVariableAsParameter(e, p);
         case RESOURCE_VARIABLE:
             return visitVariableAsResourceVariable(e, p);
         default:
             throw new AssertionError("Bad kind " + k + " for VariableElement" + e);
         }
     }
     /**
      * Visits an {@code ENUM_CONSTANT} variable element by calling
      * {@code defaultAction}.
      *
      * @param e the element to visit
      * @param p a visitor-specified parameter
      * @return  the result of {@code defaultAction}
      */
     public R visitVariableAsEnumConstant(VariableElement e, P p) {
         return defaultAction(e, p);
     }
     /**
      * Visits an {@code EXCEPTION_PARAMETER} variable element by calling
      * {@code defaultAction}.
      *
      * @param e the element to visit
      * @param p a visitor-specified parameter
      * @return  the result of {@code defaultAction}
      */
     public R visitVariableAsExceptionParameter(VariableElement e, P p) {
         return defaultAction(e, p);
     }
     /**
      * Visits a {@code FIELD} variable element by calling
      * {@code defaultAction}.
      *
      * @param e the element to visit
      * @param p a visitor-specified parameter
      * @return  the result of {@code defaultAction}
      */
     public R visitVariableAsField(VariableElement e, P p) {
         return defaultAction(e, p);
     }
     /**
      * Visits a {@code LOCAL_VARIABLE} variable element by calling
      * {@code defaultAction}.
      *
      * @param e the element to visit
      * @param p a visitor-specified parameter
      * @return  the result of {@code defaultAction}
      */
     public R visitVariableAsLocalVariable(VariableElement e, P p) {
         return defaultAction(e, p);
     }
     /**
      * Visits a {@code PARAMETER} variable element by calling
      * {@code defaultAction}.
      *
      * @param e the element to visit
      * @param p a visitor-specified parameter
      * @return  the result of {@code defaultAction}
      */
     public R visitVariableAsParameter(VariableElement e, P p) {
         return defaultAction(e, p);
     }
     /**
      * Visits a {@code RESOURCE_VARIABLE} variable element by calling
      * {@code visitUnknown}.
      *
      * @param e the element to visit
      * @param p a visitor-specified parameter
      * @return  the result of {@code visitUnknown}
      *
      * @since 1.7
      */
     public R visitVariableAsResourceVariable(VariableElement e, P p) {
         return visitUnknown(e, p);
     }
     /**
      * Visits an executable element, dispatching to the visit method
      * for the specific {@linkplain ElementKind kind} of executable,
      * {@code CONSTRUCTOR}, {@code INSTANCE_INIT}, {@code METHOD}, or
      * {@code STATIC_INIT}.
      *
      * @param e {@inheritDoc}
      * @param p {@inheritDoc}
      * @return  the result of the kind-specific visit method
      */
     @Override
     public R visitExecutable(ExecutableElement e, P p) {
         ElementKind k = e.getKind();
         switch(k) {
         case CONSTRUCTOR:
             return visitExecutableAsConstructor(e, p);
         case INSTANCE_INIT:
             return visitExecutableAsInstanceInit(e, p);
         case METHOD:
             return visitExecutableAsMethod(e, p);
         case STATIC_INIT:
             return visitExecutableAsStaticInit(e, p);
         default:
             throw new AssertionError("Bad kind " + k + " for ExecutableElement" + e);
         }
     }
     /**
      * Visits a {@code CONSTRUCTOR} executable element by calling
      * {@code defaultAction}.
      *
      * @param e the element to visit
      * @param p a visitor-specified parameter
      * @return  the result of {@code defaultAction}
      */
     public R visitExecutableAsConstructor(ExecutableElement e, P p) {
         return defaultAction(e, p);
     }
     /**
      * Visits an {@code INSTANCE_INIT} executable element by calling
      * {@code defaultAction}.
      *
      * @param e the element to visit
      * @param p a visitor-specified parameter
      * @return  the result of {@code defaultAction}
      */
     public R visitExecutableAsInstanceInit(ExecutableElement e, P p) {
         return defaultAction(e, p);
     }
     /**
      * Visits a {@code METHOD} executable element by calling
      * {@code defaultAction}.
      *
      * @param e the element to visit
      * @param p a visitor-specified parameter
      * @return  the result of {@code defaultAction}
      */
     public R visitExecutableAsMethod(ExecutableElement e, P p) {
         return defaultAction(e, p);
     }
     /**
      * Visits a {@code STATIC_INIT} executable element by calling
      * {@code defaultAction}.
      *
      * @param e the element to visit
      * @param p a visitor-specified parameter
      * @return  the result of {@code defaultAction}
      */
     public R visitExecutableAsStaticInit(ExecutableElement e, P p) {
         return defaultAction(e, p);
     }
     /**
      * {@inheritDoc}
      *
      * The element argument has kind {@code TYPE_PARAMETER}.
      *
      * @param e {@inheritDoc}
      * @param p {@inheritDoc}
      * @return  {@inheritDoc}
      */
     @Override
     public R visitTypeParameter(TypeParameterElement e, P p) {
         assert e.getKind() == TYPE_PARAMETER: "Bad kind on TypeParameterElement";
         return defaultAction(e, p);
     }
 }

Mercurial > jdk8-mips64-public > langtools / annotate

src/share/classes/javax/lang/model/util/ElementKindVisitor6.java@09f65aad4759 (annotated)

src/share/classes/javax/lang/model/util/ElementKindVisitor6.java