1 /*
   2  * Copyright (c) 2010, 2011, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package javax.lang.model.util;
  27 
  28 import javax.lang.model.type.*;
  29 import javax.annotation.processing.SupportedSourceVersion;
  30 import javax.lang.model.SourceVersion;
  31 import static javax.lang.model.SourceVersion.*;
  32 
  33 /**
  34  * A simple visitor of types with default behavior appropriate for the
  35  * {@link SourceVersion#RELEASE_7 RELEASE_7} source version.
  36  *
  37  * Visit methods corresponding to {@code RELEASE_7} and earlier
  38  * language constructs call {@link #defaultAction defaultAction},
  39  * passing their arguments to {@code defaultAction}'s corresponding
  40  * parameters.
  41  *
  42  * <p> Methods in this class may be overridden subject to their
  43  * general contract.  Note that annotating methods in concrete
  44  * subclasses with {@link java.lang.Override @Override} will help
  45  * ensure that methods are overridden as intended.
  46  *
  47  * <p> <b>WARNING:</b> The {@code TypeVisitor} interface implemented
  48  * by this class may have methods added to it in the future to
  49  * accommodate new, currently unknown, language structures added to
  50  * future versions of the Java&trade; programming language.
  51  * Therefore, methods whose names begin with {@code "visit"} may be
  52  * added to this class in the future; to avoid incompatibilities,
  53  * classes which extend this class should not declare any instance
  54  * methods with names beginning with {@code "visit"}.
  55  *
  56  * <p>When such a new visit method is added, the default
  57  * implementation in this class will be to call the {@link
  58  * #visitUnknown visitUnknown} method.  A new simple type visitor
  59  * class will also be introduced to correspond to the new language
  60  * level; this visitor will have different default behavior for the
  61  * visit method in question.  When the new visitor is introduced, all
  62  * or portions of this visitor may be deprecated.
  63  *
  64  * @param <R> the return type of this visitor's methods.  Use {@link
  65  *            Void} for visitors that do not need to return results.
  66  * @param <P> the type of the additional parameter to this visitor's
  67  *            methods.  Use {@code Void} for visitors that do not need an
  68  *            additional parameter.
  69  *
  70  * @see SimpleTypeVisitor6
  71  * @see SimpleTypeVisitor8
  72  * @since 1.7
  73  */
  74 @SupportedSourceVersion(RELEASE_7)
  75 public class SimpleTypeVisitor7<R, P> extends SimpleTypeVisitor6<R, P> {
  76     /**
  77      * Constructor for concrete subclasses; uses {@code null} for the
  78      * default value.
  79      */
  80     protected SimpleTypeVisitor7(){
  81         super(null);
  82     }
  83 
  84     /**
  85      * Constructor for concrete subclasses; uses the argument for the
  86      * default value.
  87      *
  88      * @param defaultValue the value to assign to {@link #DEFAULT_VALUE}
  89      */
  90     protected SimpleTypeVisitor7(R defaultValue){
  91         super(defaultValue);
  92     }
  93 
  94     /**
  95      * This implementation visits a {@code UnionType} by calling
  96      * {@code defaultAction}.
  97      *
  98      * @param t  {@inheritDoc}
  99      * @param p  {@inheritDoc}
 100      * @return the result of {@code defaultAction}
 101      */
 102     @Override
 103     public R visitUnion(UnionType t, P p) {
 104         return defaultAction(t, p);
 105     }
 106 }