src/share/classes/javax/lang/model/util/SimpleElementVisitor6.java

Tue, 17 Dec 2013 10:26:10 -0800

author
darcy
date
Tue, 17 Dec 2013 10:26:10 -0800
changeset 2223
6d1f9d1fd585
parent 1522
09f65aad4759
child 2525
2eb010b6cb22
permissions
-rw-r--r--

8030080: Correct misstatement in JSR 269 MR (in javax.lang.model)
Reviewed-by: jfranck

duke@1 1 /*
darcy@1522 2 * Copyright (c) 2005, 2013, Oracle and/or its affiliates. All rights reserved.
duke@1 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
duke@1 4 *
duke@1 5 * This code is free software; you can redistribute it and/or modify it
duke@1 6 * under the terms of the GNU General Public License version 2 only, as
ohair@554 7 * published by the Free Software Foundation. Oracle designates this
duke@1 8 * particular file as subject to the "Classpath" exception as provided
ohair@554 9 * by Oracle in the LICENSE file that accompanied this code.
duke@1 10 *
duke@1 11 * This code is distributed in the hope that it will be useful, but WITHOUT
duke@1 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
duke@1 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
duke@1 14 * version 2 for more details (a copy is included in the LICENSE file that
duke@1 15 * accompanied this code).
duke@1 16 *
duke@1 17 * You should have received a copy of the GNU General Public License version
duke@1 18 * 2 along with this work; if not, write to the Free Software Foundation,
duke@1 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
duke@1 20 *
ohair@554 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
ohair@554 22 * or visit www.oracle.com if you need additional information or have any
ohair@554 23 * questions.
duke@1 24 */
duke@1 25
duke@1 26 package javax.lang.model.util;
duke@1 27
duke@1 28 import javax.lang.model.element.*;
duke@1 29 import javax.annotation.processing.SupportedSourceVersion;
duke@1 30 import javax.lang.model.SourceVersion;
duke@1 31 import static javax.lang.model.SourceVersion.*;
duke@1 32
duke@1 33
duke@1 34 /**
duke@1 35 * A simple visitor of program elements with default behavior
duke@1 36 * appropriate for the {@link SourceVersion#RELEASE_6 RELEASE_6}
duke@1 37 * source version.
duke@1 38 *
duke@1 39 * Visit methods corresponding to {@code RELEASE_6} language
darcy@851 40 * constructs call {@link #defaultAction defaultAction}, passing their
darcy@851 41 * arguments to {@code defaultAction}'s corresponding parameters.
darcy@851 42 *
darcy@851 43 * For constructs introduced in {@code RELEASE_7} and later, {@code
darcy@851 44 * visitUnknown} is called instead.
duke@1 45 *
duke@1 46 * <p> Methods in this class may be overridden subject to their
duke@1 47 * general contract. Note that annotating methods in concrete
duke@1 48 * subclasses with {@link java.lang.Override @Override} will help
duke@1 49 * ensure that methods are overridden as intended.
duke@1 50 *
duke@1 51 * <p> <b>WARNING:</b> The {@code ElementVisitor} interface
duke@1 52 * implemented by this class may have methods added to it in the
duke@1 53 * future to accommodate new, currently unknown, language structures
duke@1 54 * added to future versions of the Java&trade; programming language.
duke@1 55 * Therefore, methods whose names begin with {@code "visit"} may be
duke@1 56 * added to this class in the future; to avoid incompatibilities,
duke@1 57 * classes which extend this class should not declare any instance
duke@1 58 * methods with names beginning with {@code "visit"}.
duke@1 59 *
duke@1 60 * <p>When such a new visit method is added, the default
duke@1 61 * implementation in this class will be to call the {@link
duke@1 62 * #visitUnknown visitUnknown} method. A new simple element visitor
duke@1 63 * class will also be introduced to correspond to the new language
duke@1 64 * level; this visitor will have different default behavior for the
duke@1 65 * visit method in question. When the new visitor is introduced, all
duke@1 66 * or portions of this visitor may be deprecated.
duke@1 67 *
darcy@1522 68 * <p>Note that adding a default implementation of a new visit method
darcy@1522 69 * in a visitor class will occur instead of adding a <em>default
darcy@1522 70 * method</em> directly in the visitor interface since a Java SE 8
darcy@1522 71 * language feature cannot be used to this version of the API since
darcy@1522 72 * this version is required to be runnable on Java SE 7
darcy@1522 73 * implementations. Future versions of the API that are only required
darcy@1522 74 * to run on Java SE 8 and later may take advantage of default methods
darcy@1522 75 * in this situation.
darcy@1522 76 *
duke@1 77 * @param <R> the return type of this visitor's methods. Use {@code Void}
duke@1 78 * for visitors that do not need to return results.
duke@1 79 * @param <P> the type of the additional parameter to this visitor's methods. Use {@code Void}
duke@1 80 * for visitors that do not need an additional parameter.
duke@1 81 *
duke@1 82 * @author Joseph D. Darcy
duke@1 83 * @author Scott Seligman
duke@1 84 * @author Peter von der Ah&eacute;
darcy@575 85 *
darcy@575 86 * @see SimpleElementVisitor7
darcy@1054 87 * @see SimpleElementVisitor8
duke@1 88 * @since 1.6
duke@1 89 */
duke@1 90 @SupportedSourceVersion(RELEASE_6)
duke@1 91 public class SimpleElementVisitor6<R, P> extends AbstractElementVisitor6<R, P> {
duke@1 92 /**
duke@1 93 * Default value to be returned; {@link #defaultAction
duke@1 94 * defaultAction} returns this value unless the method is
duke@1 95 * overridden.
duke@1 96 */
duke@1 97 protected final R DEFAULT_VALUE;
duke@1 98
duke@1 99 /**
duke@1 100 * Constructor for concrete subclasses; uses {@code null} for the
duke@1 101 * default value.
duke@1 102 */
duke@1 103 protected SimpleElementVisitor6(){
duke@1 104 DEFAULT_VALUE = null;
duke@1 105 }
duke@1 106
duke@1 107 /**
duke@1 108 * Constructor for concrete subclasses; uses the argument for the
duke@1 109 * default value.
duke@1 110 *
duke@1 111 * @param defaultValue the value to assign to {@link #DEFAULT_VALUE}
duke@1 112 */
duke@1 113 protected SimpleElementVisitor6(R defaultValue){
duke@1 114 DEFAULT_VALUE = defaultValue;
duke@1 115 }
duke@1 116 /**
duke@1 117 * The default action for visit methods. The implementation in
duke@1 118 * this class just returns {@link #DEFAULT_VALUE}; subclasses will
duke@1 119 * commonly override this method.
duke@1 120 *
duke@1 121 * @param e the element to process
duke@1 122 * @param p a visitor-specified parameter
duke@1 123 * @return {@code DEFAULT_VALUE} unless overridden
duke@1 124 */
duke@1 125 protected R defaultAction(Element e, P p) {
duke@1 126 return DEFAULT_VALUE;
duke@1 127 }
duke@1 128
duke@1 129 /**
duke@1 130 * {@inheritDoc} This implementation calls {@code defaultAction}.
duke@1 131 *
duke@1 132 * @param e {@inheritDoc}
duke@1 133 * @param p {@inheritDoc}
duke@1 134 * @return the result of {@code defaultAction}
duke@1 135 */
duke@1 136 public R visitPackage(PackageElement e, P p) {
duke@1 137 return defaultAction(e, p);
duke@1 138 }
duke@1 139
duke@1 140 /**
duke@1 141 * {@inheritDoc} This implementation calls {@code defaultAction}.
duke@1 142 *
duke@1 143 * @param e {@inheritDoc}
duke@1 144 * @param p {@inheritDoc}
duke@1 145 * @return the result of {@code defaultAction}
duke@1 146 */
duke@1 147 public R visitType(TypeElement e, P p) {
duke@1 148 return defaultAction(e, p);
duke@1 149 }
duke@1 150
duke@1 151 /**
darcy@851 152 * {@inheritDoc}
darcy@851 153 *
darcy@851 154 * This implementation calls {@code defaultAction}, unless the
darcy@851 155 * element is a {@code RESOURCE_VARIABLE} in which case {@code
darcy@851 156 * visitUnknown} is called.
duke@1 157 *
duke@1 158 * @param e {@inheritDoc}
duke@1 159 * @param p {@inheritDoc}
darcy@851 160 * @return the result of {@code defaultAction} or {@code visitUnknown}
duke@1 161 */
duke@1 162 public R visitVariable(VariableElement e, P p) {
darcy@851 163 if (e.getKind() != ElementKind.RESOURCE_VARIABLE)
darcy@851 164 return defaultAction(e, p);
darcy@851 165 else
darcy@851 166 return visitUnknown(e, p);
duke@1 167 }
duke@1 168
duke@1 169 /**
duke@1 170 * {@inheritDoc} This implementation calls {@code defaultAction}.
duke@1 171 *
duke@1 172 * @param e {@inheritDoc}
duke@1 173 * @param p {@inheritDoc}
duke@1 174 * @return the result of {@code defaultAction}
duke@1 175 */
duke@1 176 public R visitExecutable(ExecutableElement e, P p) {
duke@1 177 return defaultAction(e, p);
duke@1 178 }
duke@1 179
duke@1 180 /**
duke@1 181 * {@inheritDoc} This implementation calls {@code defaultAction}.
duke@1 182 *
duke@1 183 * @param e {@inheritDoc}
duke@1 184 * @param p {@inheritDoc}
duke@1 185 * @return the result of {@code defaultAction}
duke@1 186 */
duke@1 187 public R visitTypeParameter(TypeParameterElement e, P p) {
duke@1 188 return defaultAction(e, p);
duke@1 189 }
duke@1 190 }

mercurial