1 /* 2 * Copyright (c) 2010, 2013, 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.annotation.processing.SupportedSourceVersion; 29 import javax.lang.model.SourceVersion; 30 import javax.lang.model.element.*; 31 import static javax.lang.model.SourceVersion.*; 32 33 /** 34 * A visitor of program elements based on their {@linkplain 35 * ElementKind kind} with default behavior appropriate for the {@link 36 * SourceVersion#RELEASE_7 RELEASE_7} source version. For {@linkplain 37 * Element elements} <tt><i>XYZ</i></tt> that may have more than one 38 * kind, the <tt>visit<i>XYZ</i></tt> methods in this class delegate 39 * to the <tt>visit<i>XYZKind</i></tt> method corresponding to the 40 * first argument's kind. The <tt>visit<i>XYZKind</i></tt> methods 41 * call {@link #defaultAction defaultAction}, passing their arguments 42 * to {@code defaultAction}'s corresponding parameters. 43 * 44 * <p> Methods in this class may be overridden subject to their 45 * general contract. Note that annotating methods in concrete 46 * subclasses with {@link java.lang.Override @Override} will help 47 * ensure that methods are overridden as intended. 48 * 49 * <p> <b>WARNING:</b> The {@code ElementVisitor} interface 50 * implemented by this class may have methods added to it or the 51 * {@code ElementKind} {@code enum} used in this case may have 52 * constants added to it in the future to accommodate new, currently 53 * unknown, language structures added to future versions of the 54 * Java™ programming language. Therefore, methods whose names 55 * begin with {@code "visit"} may be added to this class in the 56 * future; to avoid incompatibilities, classes which extend this class 57 * should not declare any instance methods with names beginning with 58 * {@code "visit"}. 59 * 60 * <p>When such a new visit method is added, the default 61 * implementation in this class will be to call the {@link 62 * #visitUnknown visitUnknown} method. A new abstract element kind 63 * visitor class will also be introduced to correspond to the new 64 * language level; this visitor will have different default behavior 65 * for the visit method in question. When the new visitor is 66 * introduced, all or portions of this visitor may be deprecated. 67 * 68 * <p>Note that adding a default implementation of a new visit method 69 * in a visitor class will occur instead of adding a <em>default 70 * method</em> directly in the visitor interface since a Java SE 8 71 * language feature cannot be used to this version of the API since 72 * this version is required to be runnable on Java SE 7 73 * implementations. Future versions of the API that are only required 74 * to run on Java SE 8 and later may take advantage of default methods 75 * in this situation. 76 * 77 * @param <R> the return type of this visitor's methods. Use {@link 78 * Void} for visitors that do not need to return results. 79 * @param <P> the type of the additional parameter to this visitor's 80 * methods. Use {@code Void} for visitors that do not need an 81 * additional parameter. 82 * 83 * @see ElementKindVisitor6 84 * @see ElementKindVisitor8 85 * @since 1.7 86 */ 87 @SupportedSourceVersion(RELEASE_7) 88 public class ElementKindVisitor7<R, P> extends ElementKindVisitor6<R, P> { 89 /** 90 * Constructor for concrete subclasses; uses {@code null} for the 91 * default value. 92 */ ElementKindVisitor7()93 protected ElementKindVisitor7() { 94 super(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 */ ElementKindVisitor7(R defaultValue)103 protected ElementKindVisitor7(R defaultValue) { 104 super(defaultValue); 105 } 106 107 /** 108 * Visits a {@code RESOURCE_VARIABLE} variable element by calling 109 * {@code defaultAction}. 110 * 111 * @param e {@inheritDoc} 112 * @param p {@inheritDoc} 113 * @return the result of {@code defaultAction} 114 */ 115 @Override visitVariableAsResourceVariable(VariableElement e, P p)116 public R visitVariableAsResourceVariable(VariableElement e, P p) { 117 return defaultAction(e, p); 118 } 119 } 120