1 /* 2 * Copyright (c) 2010, 2019, 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.element.*; 29 import javax.annotation.processing.SupportedSourceVersion; 30 import javax.lang.model.SourceVersion; 31 import static javax.lang.model.SourceVersion.*; 32 33 34 /** 35 * A scanning visitor of program elements with default behavior 36 * appropriate for the {@link SourceVersion#RELEASE_7 RELEASE_7} 37 * source version. The <code>visit<i>Xyz</i></code> methods in this 38 * class scan their component elements by calling {@code scan} on 39 * their {@linkplain Element#getEnclosedElements enclosed elements}, 40 * {@linkplain ExecutableElement#getParameters parameters}, etc., as 41 * indicated in the individual method specifications. A subclass can 42 * control the order elements are visited by overriding the 43 * <code>visit<i>Xyz</i></code> methods. Note that clients of a scanner 44 * may get the desired behavior be invoking {@code v.scan(e, p)} rather 45 * than {@code v.visit(e, p)} on the root objects of interest. 46 * 47 * <p>When a subclass overrides a <code>visit<i>Xyz</i></code> method, the 48 * new method can cause the enclosed elements to be scanned in the 49 * default way by calling <code>super.visit<i>Xyz</i></code>. In this 50 * fashion, the concrete visitor can control the ordering of traversal 51 * over the component elements with respect to the additional 52 * processing; for example, consistently calling 53 * <code>super.visit<i>Xyz</i></code> at the start of the overridden 54 * methods will yield a preorder traversal, etc. If the component 55 * elements should be traversed in some other order, instead of 56 * calling <code>super.visit<i>Xyz</i></code>, an overriding visit method 57 * should call {@code scan} with the elements in the desired order. 58 * 59 * <p> Methods in this class may be overridden subject to their 60 * general contract. Note that annotating methods in concrete 61 * subclasses with {@link java.lang.Override @Override} will help 62 * ensure that methods are overridden as intended. 63 * 64 * <p> <b>WARNING:</b> The {@code ElementVisitor} interface 65 * implemented by this class may have methods added to it in the 66 * future to accommodate new, currently unknown, language structures 67 * added to future versions of the Java™ programming language. 68 * Therefore, methods whose names begin with {@code "visit"} may be 69 * added to this class in the future; to avoid incompatibilities, 70 * classes which extend this class should not declare any instance 71 * methods with names beginning with {@code "visit"}. 72 * 73 * <p>When such a new visit method is added, the default 74 * implementation in this class will be to call the {@link 75 * #visitUnknown visitUnknown} method. A new element scanner visitor 76 * class will also be introduced to correspond to the new language 77 * level; this visitor will have different default behavior for the 78 * visit method in question. When the new visitor is introduced, all 79 * or portions of this visitor may be deprecated. 80 * 81 * @param <R> the return type of this visitor's methods. Use {@link 82 * Void} for visitors that do not need to return results. 83 * @param <P> the type of the additional parameter to this visitor's 84 * methods. Use {@code Void} for visitors that do not need an 85 * additional parameter. 86 * 87 * @see ElementScanner6 88 * @see ElementScanner8 89 * @see ElementScanner9 90 * @see ElementScanner14 91 * @since 1.7 92 */ 93 @SupportedSourceVersion(RELEASE_7) 94 public class ElementScanner7<R, P> extends ElementScanner6<R, P> { 95 /** 96 * Constructor for concrete subclasses; uses {@code null} for the 97 * default value. 98 * 99 * @deprecated Release 7 is obsolete; update to a visitor for a newer 100 * release level. 101 */ 102 @Deprecated(since="12") ElementScanner7()103 protected ElementScanner7(){ 104 super(null); // Superclass constructor deprecated too 105 } 106 107 /** 108 * Constructor for concrete subclasses; uses the argument for the 109 * default value. 110 * 111 * @param defaultValue the default value 112 * 113 * @deprecated Release 7 is obsolete; update to a visitor for a newer 114 * release level. 115 */ 116 @Deprecated(since="12") ElementScanner7(R defaultValue)117 protected ElementScanner7(R defaultValue){ 118 super(defaultValue); // Superclass constructor deprecated too 119 } 120 121 /** 122 * {@inheritDoc} 123 * 124 * @implSpec This implementation scans the enclosed elements. 125 * 126 * @param e {@inheritDoc} 127 * @param p {@inheritDoc} 128 * @return the result of scanning 129 */ 130 @Override visitVariable(VariableElement e, P p)131 public R visitVariable(VariableElement e, P p) { 132 return scan(e.getEnclosedElements(), p); 133 } 134 } 135