1 /* 2 * Copyright (c) 2005, 2011, 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 defaultAction}, passing their 40 * arguments to {@code defaultAction}'s corresponding parameters. 41 * 42 * For constructs introduced in {@code RELEASE_7} and later, {@code 43 * visitUnknown} is called instead. 44 * 45 * <p> Methods in this class may be overridden subject to their 46 * general contract. Note that annotating methods in concrete 47 * subclasses with {@link java.lang.Override @Override} will help 48 * ensure that methods are overridden as intended. 49 * 50 * <p> <b>WARNING:</b> The {@code TypeVisitor} interface implemented 51 * by this class may have methods added to it in the future to 52 * accommodate new, currently unknown, language structures added to 53 * future versions of the Java™ programming language. 54 * Therefore, methods whose names begin with {@code "visit"} may be 55 * added to this class in the future; to avoid incompatibilities, 56 * classes which extend this class should not declare any instance 57 * methods with names beginning with {@code "visit"}. 58 * 59 * <p>When such a new visit method is added, the default 60 * implementation in this class will be to call the {@link 61 * #visitUnknown visitUnknown} method. A new simple type visitor 62 * class will also be introduced to correspond to the new language 63 * level; this visitor will have different default behavior for the 64 * visit method in question. When the new visitor is introduced, all 65 * or portions of this visitor may be deprecated. 66 * 67 * @param <R> the return type of this visitor's methods. Use {@link 68 * Void} for visitors that do not need to return results. 69 * @param <P> the type of the additional parameter to this visitor's 70 * methods. Use {@code Void} for visitors that do not need an 71 * additional parameter. 72 * 73 * @author Joseph D. Darcy 74 * @author Scott Seligman 75 * @author Peter von der Ahé 76 * 77 * @see SimpleTypeVisitor7 78 * @since 1.6 79 */ 80 @SupportedSourceVersion(RELEASE_6) 81 public class SimpleTypeVisitor6<R, P> extends AbstractTypeVisitor6<R, P> { 82 /** 83 * Default value to be returned; {@link #defaultAction 84 * defaultAction} returns this value unless the method is 85 * overridden. 86 */ 87 protected final R DEFAULT_VALUE; 88 89 /** 90 * Constructor for concrete subclasses; uses {@code null} for the 91 * default value. 92 */ 93 protected SimpleTypeVisitor6(){ 94 DEFAULT_VALUE = null; 95 } 96 97 /** 98 * Constructor for concrete subclasses; uses the argument for the 99 * default value. 100 * 101 * @param defaultValue the value to assign to {@link #DEFAULT_VALUE} 102 */ 103 protected SimpleTypeVisitor6(R defaultValue){ 104 DEFAULT_VALUE = defaultValue; 105 } 106 107 /** 108 * The default action for visit methods. The implementation in 109 * this class just returns {@link #DEFAULT_VALUE}; subclasses will 110 * commonly override this method. 111 */ 112 protected R defaultAction(TypeMirror e, P p) { 113 return DEFAULT_VALUE; 114 } 115 116 /** 117 * {@inheritDoc} This implementation calls {@code defaultAction}. 118 * 119 * @param t {@inheritDoc} 120 * @param p {@inheritDoc} 121 * @return the result of {@code defaultAction} 122 */ 123 public R visitPrimitive(PrimitiveType t, P p) { 124 return defaultAction(t, p); 125 } 126 127 /** 128 * {@inheritDoc} This implementation calls {@code defaultAction}. 129 * 130 * @param t {@inheritDoc} 131 * @param p {@inheritDoc} 132 * @return the result of {@code defaultAction} 133 */ 134 public R visitNull(NullType t, P p){ 135 return defaultAction(t, p); 136 } 137 138 /** 139 * {@inheritDoc} This implementation calls {@code defaultAction}. 140 * 141 * @param t {@inheritDoc} 142 * @param p {@inheritDoc} 143 * @return the result of {@code defaultAction} 144 */ 145 public R visitArray(ArrayType t, P p){ 146 return defaultAction(t, p); 147 } 148 149 /** 150 * {@inheritDoc} This implementation calls {@code defaultAction}. 151 * 152 * @param t {@inheritDoc} 153 * @param p {@inheritDoc} 154 * @return the result of {@code defaultAction} 155 */ 156 public R visitDeclared(DeclaredType t, P p){ 157 return defaultAction(t, p); 158 } 159 160 /** 161 * {@inheritDoc} This implementation calls {@code defaultAction}. 162 * 163 * @param t {@inheritDoc} 164 * @param p {@inheritDoc} 165 * @return the result of {@code defaultAction} 166 */ 167 public R visitError(ErrorType t, P p){ 168 return defaultAction(t, p); 169 } 170 171 /** 172 * {@inheritDoc} This implementation calls {@code defaultAction}. 173 * 174 * @param t {@inheritDoc} 175 * @param p {@inheritDoc} 176 * @return the result of {@code defaultAction} 177 */ 178 public R visitTypeVariable(TypeVariable t, P p){ 179 return defaultAction(t, p); 180 } 181 182 /** 183 * {@inheritDoc} This implementation calls {@code defaultAction}. 184 * 185 * @param t {@inheritDoc} 186 * @param p {@inheritDoc} 187 * @return the result of {@code defaultAction} 188 */ 189 public R visitWildcard(WildcardType t, P p){ 190 return defaultAction(t, p); 191 } 192 193 /** 194 * {@inheritDoc} This implementation calls {@code defaultAction}. 195 * 196 * @param t {@inheritDoc} 197 * @param p {@inheritDoc} 198 * @return the result of {@code defaultAction} 199 */ 200 public R visitExecutable(ExecutableType t, P p) { 201 return defaultAction(t, p); 202 } 203 204 /** 205 * {@inheritDoc} This implementation calls {@code defaultAction}. 206 * 207 * @param t {@inheritDoc} 208 * @param p {@inheritDoc} 209 * @return the result of {@code defaultAction} 210 */ 211 public R visitNoType(NoType t, P p){ 212 return defaultAction(t, p); 213 } 214 }