AbstractTypeVisitor6.java revision 4031:17249d1d92fe
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.annotation.processing.SupportedSourceVersion; 29import javax.lang.model.type.*; 30 31import static javax.lang.model.SourceVersion.*; 32 33/** 34 * A skeletal visitor of types with default behavior appropriate for 35 * the {@link javax.lang.model.SourceVersion#RELEASE_6 RELEASE_6} 36 * source version. 37 * 38 * <p> <b>WARNING:</b> The {@code TypeVisitor} interface implemented 39 * by this class may have methods added to it in the future to 40 * accommodate new, currently unknown, language structures added to 41 * future versions of the Java™ programming language. 42 * Therefore, methods whose names begin with {@code "visit"} may be 43 * added to this class in the future; to avoid incompatibilities, 44 * classes which extend this class should not declare any instance 45 * methods with names beginning with {@code "visit"}. 46 * 47 * <p>When such a new visit method is added, the default 48 * implementation in this class will be to call the {@link 49 * #visitUnknown visitUnknown} method. A new abstract type visitor 50 * class will also be introduced to correspond to the new language 51 * level; this visitor will have different default behavior for the 52 * visit method in question. When the new visitor is introduced, all 53 * or portions of this visitor may be deprecated. 54 * 55 * @param <R> the return type of this visitor's methods. Use {@link 56 * Void} for visitors that do not need to return results. 57 * @param <P> the type of the additional parameter to this visitor's 58 * methods. Use {@code Void} for visitors that do not need an 59 * additional parameter. 60 * 61 * @author Joseph D. Darcy 62 * @author Scott Seligman 63 * @author Peter von der Ahé 64 * 65 * @see AbstractTypeVisitor7 66 * @see AbstractTypeVisitor8 67 * @see AbstractTypeVisitor9 68 * @since 1.6 69 */ 70@SupportedSourceVersion(RELEASE_6) 71public abstract class AbstractTypeVisitor6<R, P> implements TypeVisitor<R, P> { 72 /** 73 * Constructor for concrete subclasses to call. 74 * @deprecated Release 6 is obsolete; update to a visitor for a newer 75 * release level. 76 */ 77 @Deprecated 78 protected AbstractTypeVisitor6() {} 79 80 /** 81 * Visits any type mirror as if by passing itself to that type 82 * mirror's {@link TypeMirror#accept accept} method. The 83 * invocation {@code v.visit(t, p)} is equivalent to {@code 84 * t.accept(v, p)}. 85 * 86 * @param t the type to visit 87 * @param p a visitor-specified parameter 88 * @return a visitor-specified result 89 */ 90 public final R visit(TypeMirror t, P p) { 91 return t.accept(this, p); 92 } 93 94 /** 95 * Visits any type mirror as if by passing itself to that type 96 * mirror's {@link TypeMirror#accept accept} method and passing 97 * {@code null} for the additional parameter. The invocation 98 * {@code v.visit(t)} is equivalent to {@code t.accept(v, null)}. 99 * 100 * @param t the type to visit 101 * @return a visitor-specified result 102 */ 103 public final R visit(TypeMirror t) { 104 return t.accept(this, null); 105 } 106 107 /** 108 * {@inheritDoc} 109 * 110 * @implSpec Visits a {@code UnionType} element by calling {@code 111 * visitUnknown}. 112 * 113 * @param t {@inheritDoc} 114 * @param p {@inheritDoc} 115 * @return the result of {@code visitUnknown} 116 * 117 * @since 1.7 118 */ 119 public R visitUnion(UnionType t, P p) { 120 return visitUnknown(t, p); 121 } 122 123 /** 124 * {@inheritDoc} 125 * 126 * @implSpec Visits an {@code IntersectionType} element by calling {@code 127 * visitUnknown}. 128 * 129 * @param t {@inheritDoc} 130 * @param p {@inheritDoc} 131 * @return the result of {@code visitUnknown} 132 * 133 * @since 1.8 134 */ 135 @Override 136 public R visitIntersection(IntersectionType t, P p) { 137 return visitUnknown(t, p); 138 } 139 140 /** 141 * {@inheritDoc} 142 * 143 * @implSpec The default implementation of this method in {@code 144 * AbstractTypeVisitor6} will always throw {@code 145 * new UnknownTypeException(t, p)}. This behavior is not required of a 146 * subclass. 147 * 148 * @param t {@inheritDoc} 149 * @param p {@inheritDoc} 150 * @return a visitor-specified result 151 * @throws UnknownTypeException 152 * a visitor implementation may optionally throw this exception 153 */ 154 @Override 155 public R visitUnknown(TypeMirror t, P p) { 156 throw new UnknownTypeException(t, p); 157 } 158} 159