Mercurial > jdk8-mips64-public > langtools / file comparison
comparison: src/share/classes/javax/lang/model/util/SimpleElementVisitor6.java
src/share/classes/javax/lang/model/util/SimpleElementVisitor6.java
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| 1 /* | |
| 2 * Copyright (c) 2005, 2013, 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.element.*; | |
| 29 import javax.annotation.processing.SupportedSourceVersion; | |
| 30 import javax.lang.model.SourceVersion; | |
| 31 import 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 * <p>Note that adding a default implementation of a new visit method | |
| 69 * in a visitor class will occur instead of adding a <em>default | |
| 70 * method</em> directly in the visitor interface since a Java SE 8 | |
| 71 * language feature cannot be used to this version of the API since | |
| 72 * this version is required to be runnable on Java SE 7 | |
| 73 * implementations. Future versions of the API that are only required | |
| 74 * to run on Java SE 8 and later may take advantage of default methods | |
| 75 * in this situation. | |
| 76 * | |
| 77 * @param <R> the return type of this visitor's methods. Use {@code Void} | |
| 78 * for visitors that do not need to return results. | |
| 79 * @param <P> the type of the additional parameter to this visitor's methods. Use {@code Void} | |
| 80 * for visitors that do not need an additional parameter. | |
| 81 * | |
| 82 * @author Joseph D. Darcy | |
| 83 * @author Scott Seligman | |
| 84 * @author Peter von der Ahé | |
| 85 * | |
| 86 * @see SimpleElementVisitor7 | |
| 87 * @see SimpleElementVisitor8 | |
| 88 * @since 1.6 | |
| 89 */ | |
| 90 @SupportedSourceVersion(RELEASE_6) | |
| 91 public class SimpleElementVisitor6<R, P> extends AbstractElementVisitor6<R, P> { | |
| 92 /** | |
| 93 * Default value to be returned; {@link #defaultAction | |
| 94 * defaultAction} returns this value unless the method is | |
| 95 * overridden. | |
| 96 */ | |
| 97 protected final R DEFAULT_VALUE; | |
| 98 | |
| 99 /** | |
| 100 * Constructor for concrete subclasses; uses {@code null} for the | |
| 101 * default value. | |
| 102 */ | |
| 103 protected SimpleElementVisitor6(){ | |
| 104 DEFAULT_VALUE = null; | |
| 105 } | |
| 106 | |
| 107 /** | |
| 108 * Constructor for concrete subclasses; uses the argument for the | |
| 109 * default value. | |
| 110 * | |
| 111 * @param defaultValue the value to assign to {@link #DEFAULT_VALUE} | |
| 112 */ | |
| 113 protected SimpleElementVisitor6(R defaultValue){ | |
| 114 DEFAULT_VALUE = defaultValue; | |
| 115 } | |
| 116 /** | |
| 117 * The default action for visit methods. The implementation in | |
| 118 * this class just returns {@link #DEFAULT_VALUE}; subclasses will | |
| 119 * commonly override this method. | |
| 120 * | |
| 121 * @param e the element to process | |
| 122 * @param p a visitor-specified parameter | |
| 123 * @return {@code DEFAULT_VALUE} unless overridden | |
| 124 */ | |
| 125 protected R defaultAction(Element e, P p) { | |
| 126 return DEFAULT_VALUE; | |
| 127 } | |
| 128 | |
| 129 /** | |
| 130 * {@inheritDoc} This implementation calls {@code defaultAction}. | |
| 131 * | |
| 132 * @param e {@inheritDoc} | |
| 133 * @param p {@inheritDoc} | |
| 134 * @return the result of {@code defaultAction} | |
| 135 */ | |
| 136 public R visitPackage(PackageElement e, P p) { | |
| 137 return defaultAction(e, p); | |
| 138 } | |
| 139 | |
| 140 /** | |
| 141 * {@inheritDoc} This implementation calls {@code defaultAction}. | |
| 142 * | |
| 143 * @param e {@inheritDoc} | |
| 144 * @param p {@inheritDoc} | |
| 145 * @return the result of {@code defaultAction} | |
| 146 */ | |
| 147 public R visitType(TypeElement e, P p) { | |
| 148 return defaultAction(e, p); | |
| 149 } | |
| 150 | |
| 151 /** | |
| 152 * {@inheritDoc} | |
| 153 * | |
| 154 * This implementation calls {@code defaultAction}, unless the | |
| 155 * element is a {@code RESOURCE_VARIABLE} in which case {@code | |
| 156 * visitUnknown} is called. | |
| 157 * | |
| 158 * @param e {@inheritDoc} | |
| 159 * @param p {@inheritDoc} | |
| 160 * @return the result of {@code defaultAction} or {@code visitUnknown} | |
| 161 */ | |
| 162 public R visitVariable(VariableElement e, P p) { | |
| 163 if (e.getKind() != ElementKind.RESOURCE_VARIABLE) | |
| 164 return defaultAction(e, p); | |
| 165 else | |
| 166 return visitUnknown(e, p); | |
| 167 } | |
| 168 | |
| 169 /** | |
| 170 * {@inheritDoc} This implementation calls {@code defaultAction}. | |
| 171 * | |
| 172 * @param e {@inheritDoc} | |
| 173 * @param p {@inheritDoc} | |
| 174 * @return the result of {@code defaultAction} | |
| 175 */ | |
| 176 public R visitExecutable(ExecutableElement e, P p) { | |
| 177 return defaultAction(e, p); | |
| 178 } | |
| 179 | |
| 180 /** | |
| 181 * {@inheritDoc} This implementation calls {@code defaultAction}. | |
| 182 * | |
| 183 * @param e {@inheritDoc} | |
| 184 * @param p {@inheritDoc} | |
| 185 * @return the result of {@code defaultAction} | |
| 186 */ | |
| 187 public R visitTypeParameter(TypeParameterElement e, P p) { | |
| 188 return defaultAction(e, p); | |
| 189 } | |
| 190 } |
