1 /* 2 * Copyright (c) 2005, 2020, 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.annotation.processing.SupportedSourceVersion; 29 import javax.lang.model.SourceVersion; 30 import javax.lang.model.element.*; 31 import static javax.lang.model.SourceVersion.*; 32 33 34 /** 35 * A skeletal visitor of program elements with default behavior 36 * appropriate for the {@link SourceVersion#RELEASE_6 RELEASE_6} 37 * source version. 38 * 39 * @apiNote 40 * <p id=note_for_subclasses><strong>WARNING:</strong> The {@code 41 * ElementVisitor} interface implemented by this class may have 42 * methods added to it in the future to accommodate new, currently 43 * unknown, language structures added to future versions of the 44 * Java programming language. Therefore, methods whose names 45 * begin with {@code "visit"} may be added to this class in the 46 * future; to avoid incompatibilities, classes and subclasses which 47 * extend this class should not declare any instance methods with 48 * names beginning with {@code "visit"}.</p> 49 * 50 * <p>When such a new visit method is added, the default 51 * implementation in this class will be to directly or indirectly call 52 * the {@link #visitUnknown visitUnknown} method. A new abstract 53 * element visitor class will also be introduced to correspond to the 54 * new language level; this visitor will have different default 55 * behavior for the visit method in question. When a new visitor is 56 * introduced, portions of this visitor class may be deprecated, 57 * including its constructors. 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 * 69 * @see AbstractElementVisitor7 70 * @see AbstractElementVisitor8 71 * @see AbstractElementVisitor9 72 * @see AbstractElementVisitor14 73 * @since 1.6 74 */ 75 @SupportedSourceVersion(RELEASE_6) 76 public abstract class AbstractElementVisitor6<R, P> implements ElementVisitor<R, P> { 77 /** 78 * Constructor for concrete subclasses to call. 79 * @deprecated Release 6 is obsolete; update to a visitor for a newer 80 * release level. 81 */ 82 @Deprecated(since="9") 83 protected AbstractElementVisitor6(){} 84 85 /** 86 * Visits any program element as if by passing itself to that 87 * element's {@link Element#accept accept} method. The invocation 88 * {@code v.visit(elem, p)} is equivalent to {@code elem.accept(v, 89 * p)}. 90 * 91 * @param e the element to visit 92 * @param p a visitor-specified parameter 93 * @return a visitor-specified result 94 */ 95 public final R visit(Element e, P p) { 96 return e.accept(this, p); 97 } 98 99 /** 100 * Visits any program element as if by passing itself to that 101 * element's {@link Element#accept accept} method and passing 102 * {@code null} for the additional parameter. The invocation 103 * {@code v.visit(elem)} is equivalent to {@code elem.accept(v, 104 * null)}. 105 * 106 * @param e the element to visit 107 * @return a visitor-specified result 108 */ 109 public final R visit(Element e) { 110 return e.accept(this, null); 111 } 112 113 /** 114 * {@inheritDoc} 115 * 116 * @implSpec The default implementation of this method in 117 * {@code AbstractElementVisitor6} will always throw 118 * {@code new UnknownElementException(e, p)}. 119 * This behavior is not required of a subclass. 120 * 121 * @param e {@inheritDoc} 122 * @param p {@inheritDoc} 123 * @return {@inheritDoc} 124 * @throws UnknownElementException 125 * a visitor implementation may optionally throw this exception 126 */ 127 @Override 128 public R visitUnknown(Element e, P p) { 129 throw new UnknownElementException(e, p); 130 } 131 132 /** 133 * {@inheritDoc} 134 * 135 * @implSpec Visits a {@code ModuleElement} by calling {@code 136 * visitUnknown}. 137 * 138 * @param e {@inheritDoc} 139 * @param p {@inheritDoc} 140 * @return {@inheritDoc} 141 * 142 * @since 9 143 * @spec JPMS 144 */ 145 @Override 146 public R visitModule(ModuleElement e, P p) { 147 // Use implementation from interface default method 148 return ElementVisitor.super.visitModule(e, p); 149 } 150 151 /** 152 * {@inheritDoc} 153 * 154 * @implSpec Visits a {@code RecordComponentElement} by calling {@code 155 * visitUnknown}. 156 * 157 * @param e {@inheritDoc} 158 * @param p {@inheritDoc} 159 * @return {@inheritDoc} 160 * 161 * @since 14 162 */ 163 @SuppressWarnings("preview") 164 @Override 165 public R visitRecordComponent(RecordComponentElement e, P p) { 166 // Use implementation from interface default method 167 return ElementVisitor.super.visitRecordComponent(e, p); 168 } 169 }