SimpleElementVisitor6.java revision 3884:b6960e2da008
1/* 2 * Copyright (c) 2005, 2017, 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 26package javax.lang.model.util; 27 28import javax.lang.model.element.*; 29import javax.annotation.processing.SupportedSourceVersion; 30import javax.lang.model.SourceVersion; 31import static javax.lang.model.SourceVersion.*; 32 33 34/** 35 * A simple visitor of program elements with default behavior 36 * appropriate for the {@link SourceVersion#RELEASE_6 RELEASE_6} 37 * source version. 38 * 39 * Visit methods corresponding to {@code RELEASE_6} language 40 * constructs call {@link #defaultAction defaultAction}, passing their 41 * arguments to {@code defaultAction}'s corresponding parameters. 42 * 43 * For constructs introduced in {@code RELEASE_7} and later, {@code 44 * visitUnknown} is called instead. 45 * 46 * <p> Methods in this class may be overridden subject to their 47 * general contract. Note that annotating methods in concrete 48 * subclasses with {@link java.lang.Override @Override} will help 49 * ensure that methods are overridden as intended. 50 * 51 * <p> <b>WARNING:</b> The {@code ElementVisitor} interface 52 * implemented by this class may have methods added to it in the 53 * future to accommodate new, currently unknown, language structures 54 * added to future versions of the Java™ programming language. 55 * Therefore, methods whose names begin with {@code "visit"} may be 56 * added to this class in the future; to avoid incompatibilities, 57 * classes which extend this class should not declare any instance 58 * methods with names beginning with {@code "visit"}. 59 * 60 * <p>When such a new visit method is added, the default 61 * implementation in this class will be to call the {@link 62 * #visitUnknown visitUnknown} method. A new simple element visitor 63 * class will also be introduced to correspond to the new language 64 * level; this visitor will have different default behavior for the 65 * visit method in question. When the new visitor is introduced, all 66 * or portions of this visitor may be deprecated. 67 * 68 * @param <R> the return type of this visitor's methods. Use {@code Void} 69 * for visitors that do not need to return results. 70 * @param <P> the type of the additional parameter to this visitor's methods. Use {@code Void} 71 * for visitors that do not need an additional parameter. 72 * 73 * @author Joseph D. Darcy 74 * @author Scott Seligman 75 * @author Peter von der Ahé 76 * 77 * @see SimpleElementVisitor7 78 * @see SimpleElementVisitor8 79 * @see SimpleElementVisitor9 80 * @since 1.6 81 * @deprecated Release 6 is obsolete; update to a visitor for a newer 82 * release level. 83 */ 84@Deprecated 85@SupportedSourceVersion(RELEASE_6) 86public class SimpleElementVisitor6<R, P> extends AbstractElementVisitor6<R, P> { 87 /** 88 * Default value to be returned; {@link #defaultAction 89 * defaultAction} returns this value unless the method is 90 * overridden. 91 */ 92 protected final R DEFAULT_VALUE; 93 94 /** 95 * Constructor for concrete subclasses; uses {@code null} for the 96 * default value. 97 */ 98 protected SimpleElementVisitor6(){ 99 DEFAULT_VALUE = null; 100 } 101 102 /** 103 * Constructor for concrete subclasses; uses the argument for the 104 * default value. 105 * 106 * @param defaultValue the value to assign to {@link #DEFAULT_VALUE} 107 */ 108 protected SimpleElementVisitor6(R defaultValue){ 109 DEFAULT_VALUE = defaultValue; 110 } 111 /** 112 * The default action for visit methods. The implementation in 113 * this class just returns {@link #DEFAULT_VALUE}; subclasses will 114 * commonly override this method. 115 * 116 * @param e the element to process 117 * @param p a visitor-specified parameter 118 * @return {@code DEFAULT_VALUE} unless overridden 119 */ 120 protected R defaultAction(Element e, P p) { 121 return DEFAULT_VALUE; 122 } 123 124 /** 125 * {@inheritDoc} This implementation calls {@code defaultAction}. 126 * 127 * @param e {@inheritDoc} 128 * @param p {@inheritDoc} 129 * @return the result of {@code defaultAction} 130 */ 131 public R visitPackage(PackageElement e, P p) { 132 return defaultAction(e, p); 133 } 134 135 /** 136 * {@inheritDoc} This implementation calls {@code defaultAction}. 137 * 138 * @param e {@inheritDoc} 139 * @param p {@inheritDoc} 140 * @return the result of {@code defaultAction} 141 */ 142 public R visitType(TypeElement e, P p) { 143 return defaultAction(e, p); 144 } 145 146 /** 147 * {@inheritDoc} 148 * 149 * This implementation calls {@code defaultAction}, unless the 150 * element is a {@code RESOURCE_VARIABLE} in which case {@code 151 * visitUnknown} is called. 152 * 153 * @param e {@inheritDoc} 154 * @param p {@inheritDoc} 155 * @return the result of {@code defaultAction} or {@code visitUnknown} 156 */ 157 public R visitVariable(VariableElement e, P p) { 158 if (e.getKind() != ElementKind.RESOURCE_VARIABLE) 159 return defaultAction(e, p); 160 else 161 return visitUnknown(e, p); 162 } 163 164 /** 165 * {@inheritDoc} This implementation calls {@code defaultAction}. 166 * 167 * @param e {@inheritDoc} 168 * @param p {@inheritDoc} 169 * @return the result of {@code defaultAction} 170 */ 171 public R visitExecutable(ExecutableElement e, P p) { 172 return defaultAction(e, p); 173 } 174 175 /** 176 * {@inheritDoc} This implementation calls {@code defaultAction}. 177 * 178 * @param e {@inheritDoc} 179 * @param p {@inheritDoc} 180 * @return the result of {@code defaultAction} 181 */ 182 public R visitTypeParameter(TypeParameterElement e, P p) { 183 return defaultAction(e, p); 184 } 185} 186