1 /* 2 * Copyright (c) 2005, 2010, 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.type.*; 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 types with default behavior appropriate for the 36 * {@link SourceVersion#RELEASE_6 RELEASE_6} source version. 37 * 38 * Visit methods corresponding to {@code RELEASE_6} language 39 * constructs call {@link #defaultAction}, passing their arguments to 40 * {@code defaultAction}'s corresponding parameters. 41 * 42 * <p> Methods in this class may be overridden subject to their 43 * general contract. Note that annotating methods in concrete 44 * subclasses with {@link java.lang.Override @Override} will help 45 * ensure that methods are overridden as intended. 46 * 47 * <p> <b>WARNING:</b> The {@code TypeVisitor} interface implemented 48 * by this class may have methods added to it in the future to 49 * accommodate new, currently unknown, language structures added to 50 * future versions of the Java™ programming language. 51 * Therefore, methods whose names begin with {@code "visit"} may be 52 * added to this class in the future; to avoid incompatibilities, 53 * classes which extend this class should not declare any instance 54 * methods with names beginning with {@code "visit"}. 55 * 56 * <p>When such a new visit method is added, the default 57 * implementation in this class will be to call the {@link 58 * #visitUnknown visitUnknown} method. A new simple type visitor 59 * class will also be introduced to correspond to the new language 60 * level; this visitor will have different default behavior for the 61 * visit method in question. When the new visitor is introduced, all 62 * or portions of this visitor may be deprecated. 63 * 64 * @param <R> the return type of this visitor's methods. Use {@link 65 * Void} for visitors that do not need to return results. 66 * @param <P> the type of the additional parameter to this visitor's 67 * methods. Use {@code Void} for visitors that do not need an 68 * additional parameter. 69 * 70 * @author Joseph D. Darcy 71 * @author Scott Seligman 72 * @author Peter von der Ahé 73 * 74 * @see SimpleTypeVisitor7 75 * @since 1.6 76 */ 77 @SupportedSourceVersion(RELEASE_6) 78 public class SimpleTypeVisitor6<R, P> extends AbstractTypeVisitor6<R, P> { 79 /** 80 * Default value to be returned; {@link #defaultAction 81 * defaultAction} returns this value unless the method is 82 * overridden. 83 */ 84 protected final R DEFAULT_VALUE; 85 86 /** 87 * Constructor for concrete subclasses; uses {@code null} for the 88 * default value. 89 */ 90 protected SimpleTypeVisitor6(){ 91 DEFAULT_VALUE = null; 92 } 93 94 /** 95 * Constructor for concrete subclasses; uses the argument for the 96 * default value. 97 * 98 * @param defaultValue the value to assign to {@link #DEFAULT_VALUE} 99 */ 100 protected SimpleTypeVisitor6(R defaultValue){ 101 DEFAULT_VALUE = defaultValue; 102 } 103 104 /** 105 * The default action for visit methods. The implementation in 106 * this class just returns {@link #DEFAULT_VALUE}; subclasses will 107 * commonly override this method. 108 */ 109 protected R defaultAction(TypeMirror e, P p) { 110 return DEFAULT_VALUE; 111 } 112 113 /** 114 * {@inheritDoc} This implementation calls {@code defaultAction}. 115 * 116 * @param t {@inheritDoc} 117 * @param p {@inheritDoc} 118 * @return the result of {@code defaultAction} 119 */ 120 public R visitPrimitive(PrimitiveType t, P p) { 121 return defaultAction(t, p); 122 } 123 124 /** 125 * {@inheritDoc} This implementation calls {@code defaultAction}. 126 * 127 * @param t {@inheritDoc} 128 * @param p {@inheritDoc} 129 * @return the result of {@code defaultAction} 130 */ 131 public R visitNull(NullType t, P p){ 132 return defaultAction(t, p); 133 } 134 135 /** 136 * {@inheritDoc} This implementation calls {@code defaultAction}. 137 * 138 * @param t {@inheritDoc} 139 * @param p {@inheritDoc} 140 * @return the result of {@code defaultAction} 141 */ 142 public R visitArray(ArrayType t, P p){ 143 return defaultAction(t, p); 144 } 145 146 /** 147 * {@inheritDoc} This implementation calls {@code defaultAction}. 148 * 149 * @param t {@inheritDoc} 150 * @param p {@inheritDoc} 151 * @return the result of {@code defaultAction} 152 */ 153 public R visitDeclared(DeclaredType t, P p){ 154 return defaultAction(t, p); 155 } 156 157 /** 158 * {@inheritDoc} This implementation calls {@code defaultAction}. 159 * 160 * @param t {@inheritDoc} 161 * @param p {@inheritDoc} 162 * @return the result of {@code defaultAction} 163 */ 164 public R visitError(ErrorType t, P p){ 165 return defaultAction(t, p); 166 } 167 168 /** 169 * {@inheritDoc} This implementation calls {@code defaultAction}. 170 * 171 * @param t {@inheritDoc} 172 * @param p {@inheritDoc} 173 * @return the result of {@code defaultAction} 174 */ 175 public R visitTypeVariable(TypeVariable t, P p){ 176 return defaultAction(t, p); 177 } 178 179 /** 180 * {@inheritDoc} This implementation calls {@code defaultAction}. 181 * 182 * @param t {@inheritDoc} 183 * @param p {@inheritDoc} 184 * @return the result of {@code defaultAction} 185 */ 186 public R visitWildcard(WildcardType t, P p){ 187 return defaultAction(t, p); 188 } 189 190 /** 191 * {@inheritDoc} This implementation calls {@code defaultAction}. 192 * 193 * @param t {@inheritDoc} 194 * @param p {@inheritDoc} 195 * @return the result of {@code defaultAction} 196 */ 197 public R visitExecutable(ExecutableType t, P p) { 198 return defaultAction(t, p); 199 } 200 201 /** 202 * {@inheritDoc} This implementation calls {@code defaultAction}. 203 * 204 * @param t {@inheritDoc} 205 * @param p {@inheritDoc} 206 * @return the result of {@code defaultAction} 207 */ 208 public R visitNoType(NoType t, P p){ 209 return defaultAction(t, p); 210 } 211 }