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