| 1 | /* |
| 2 | * Copyright 2005-2006 Sun Microsystems, Inc. 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. Sun designates this |
| 8 | * particular file as subject to the "Classpath" exception as provided |
| 9 | * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 22 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 23 | * have any questions. |
| 24 | */ |
| 25 | |
| 26 | package javax.lang.model.util; |
| 27 | |
| 28 | |
| 29 | import javax.lang.model.element.*; |
| 30 | import javax.annotation.processing.SupportedSourceVersion; |
| 31 | import javax.lang.model.element.*; |
| 32 | import static javax.lang.model.element.ElementKind.*; |
| 33 | import static javax.lang.model.SourceVersion.*; |
| 34 | import javax.lang.model.SourceVersion; |
| 35 | |
| 36 | |
| 37 | /** |
| 38 | * A skeletal visitor of program elements with default behavior |
| 39 | * appropriate for the {@link SourceVersion#RELEASE_6 RELEASE_6} |
| 40 | * source version. |
| 41 | * |
| 42 | * <p> <b>WARNING:</b> The {@code ElementVisitor} interface |
| 43 | * implemented by this class may have methods added to it in the |
| 44 | * future to accommodate new, currently unknown, language structures |
| 45 | * added to future versions of the Java™ programming language. |
| 46 | * Therefore, methods whose names begin with {@code "visit"} may be |
| 47 | * added to this class in the future; to avoid incompatibilities, |
| 48 | * classes which extend this class should not declare any instance |
| 49 | * methods with names beginning with {@code "visit"}. |
| 50 | * |
| 51 | * <p>When such a new visit method is added, the default |
| 52 | * implementation in this class will be to call the {@link |
| 53 | * #visitUnknown visitUnknown} method. A new abstract element visitor |
| 54 | * class will also be introduced to correspond to the new language |
| 55 | * level; this visitor will have different default behavior for the |
| 56 | * visit method in question. When the new visitor is introduced, all |
| 57 | * or portions of this visitor may be deprecated. |
| 58 | * |
| 59 | * @param <R> the return type of this visitor's methods. Use {@link |
| 60 | * Void} for visitors that do not need to return results. |
| 61 | * @param <P> the type of the additional parameter to this visitor's |
| 62 | * methods. Use {@code Void} for visitors that do not need an |
| 63 | * additional parameter. |
| 64 | * |
| 65 | * @author Joseph D. Darcy |
| 66 | * @author Scott Seligman |
| 67 | * @author Peter von der Ahé |
| 68 | * @since 1.6 |
| 69 | */ |
| 70 | @SupportedSourceVersion(RELEASE_6) |
| 71 | public abstract class AbstractElementVisitor6<R, P> implements ElementVisitor<R, P> { |
| 72 | /** |
| 73 | * Constructor for concrete subclasses to call. |
| 74 | */ |
| 75 | protected AbstractElementVisitor6(){} |
| 76 | |
| 77 | /** |
| 78 | * Visits any program element as if by passing itself to that |
| 79 | * element's {@link Element#accept accept} method. The invocation |
| 80 | * {@code v.visit(elem)} is equivalent to {@code elem.accept(v, |
| 81 | * p)}. |
| 82 | * |
| 83 | * @param e the element to visit |
| 84 | * @param p a visitor-specified parameter |
| 85 | * @return a visitor-specified result |
| 86 | */ |
| 87 | public final R visit(Element e, P p) { |
| 88 | return e.accept(this, p); |
| 89 | } |
| 90 | |
| 91 | /** |
| 92 | * Visits any program element as if by passing itself to that |
| 93 | * element's {@link Element#accept accept} method and passing |
| 94 | * {@code null} for the additional parameter. The invocation |
| 95 | * {@code v.visit(elem)} is equivalent to {@code elem.accept(v, |
| 96 | * null)}. |
| 97 | * |
| 98 | * @param e the element to visit |
| 99 | * @return a visitor-specified result |
| 100 | */ |
| 101 | public final R visit(Element e) { |
| 102 | return e.accept(this, null); |
| 103 | } |
| 104 | |
| 105 | /** |
| 106 | * {@inheritDoc} |
| 107 | * |
| 108 | * <p> The default implementation of this method in |
| 109 | * {@code AbstractElementVisitor6} will always throw |
| 110 | * {@code UnknownElementException}. |
| 111 | * This behavior is not required of a subclass. |
| 112 | * |
| 113 | * @param e the element to visit |
| 114 | * @param p a visitor-specified parameter |
| 115 | * @return a visitor-specified result |
| 116 | * @throws UnknownElementException |
| 117 | * a visitor implementation may optionally throw this exception |
| 118 | */ |
| 119 | public R visitUnknown(Element e, P p) { |
| 120 | throw new UnknownElementException(e, p); |
| 121 | } |
| 122 | } |