Mercurial > jdk8-mips64-public > langtools / file comparison
comparison: src/share/classes/javax/lang/model/util/ElementScanner7.java
src/share/classes/javax/lang/model/util/ElementScanner7.java
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| 1 /* | |
| 2 * Copyright (c) 2010, 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 static javax.lang.model.element.ElementKind.*; | |
| 31 import javax.lang.model.SourceVersion; | |
| 32 import static javax.lang.model.SourceVersion.*; | |
| 33 | |
| 34 | |
| 35 /** | |
| 36 * A scanning visitor of program elements with default behavior | |
| 37 * appropriate for the {@link SourceVersion#RELEASE_7 RELEASE_7} | |
| 38 * source version. The <tt>visit<i>XYZ</i></tt> methods in this | |
| 39 * class scan their component elements by calling {@code scan} on | |
| 40 * their {@linkplain Element#getEnclosedElements enclosed elements}, | |
| 41 * {@linkplain ExecutableElement#getParameters parameters}, etc., as | |
| 42 * indicated in the individual method specifications. A subclass can | |
| 43 * control the order elements are visited by overriding the | |
| 44 * <tt>visit<i>XYZ</i></tt> methods. Note that clients of a scanner | |
| 45 * may get the desired behavior be invoking {@code v.scan(e, p)} rather | |
| 46 * than {@code v.visit(e, p)} on the root objects of interest. | |
| 47 * | |
| 48 * <p>When a subclass overrides a <tt>visit<i>XYZ</i></tt> method, the | |
| 49 * new method can cause the enclosed elements to be scanned in the | |
| 50 * default way by calling <tt>super.visit<i>XYZ</i></tt>. In this | |
| 51 * fashion, the concrete visitor can control the ordering of traversal | |
| 52 * over the component elements with respect to the additional | |
| 53 * processing; for example, consistently calling | |
| 54 * <tt>super.visit<i>XYZ</i></tt> at the start of the overridden | |
| 55 * methods will yield a preorder traversal, etc. If the component | |
| 56 * elements should be traversed in some other order, instead of | |
| 57 * calling <tt>super.visit<i>XYZ</i></tt>, an overriding visit method | |
| 58 * should call {@code scan} with the elements in the desired order. | |
| 59 * | |
| 60 * <p> Methods in this class may be overridden subject to their | |
| 61 * general contract. Note that annotating methods in concrete | |
| 62 * subclasses with {@link java.lang.Override @Override} will help | |
| 63 * ensure that methods are overridden as intended. | |
| 64 * | |
| 65 * <p> <b>WARNING:</b> The {@code ElementVisitor} interface | |
| 66 * implemented by this class may have methods added to it in the | |
| 67 * future to accommodate new, currently unknown, language structures | |
| 68 * added to future versions of the Java™ programming language. | |
| 69 * Therefore, methods whose names begin with {@code "visit"} may be | |
| 70 * added to this class in the future; to avoid incompatibilities, | |
| 71 * classes which extend this class should not declare any instance | |
| 72 * methods with names beginning with {@code "visit"}. | |
| 73 * | |
| 74 * <p>When such a new visit method is added, the default | |
| 75 * implementation in this class will be to call the {@link | |
| 76 * #visitUnknown visitUnknown} method. A new element scanner visitor | |
| 77 * class will also be introduced to correspond to the new language | |
| 78 * level; this visitor will have different default behavior for the | |
| 79 * visit method in question. When the new visitor is introduced, all | |
| 80 * or portions of this visitor may be deprecated. | |
| 81 * | |
| 82 * @param <R> the return type of this visitor's methods. Use {@link | |
| 83 * Void} for visitors that do not need to return results. | |
| 84 * @param <P> the type of the additional parameter to this visitor's | |
| 85 * methods. Use {@code Void} for visitors that do not need an | |
| 86 * additional parameter. | |
| 87 * | |
| 88 * @see ElementScanner6 | |
| 89 * @since 1.7 | |
| 90 */ | |
| 91 @SupportedSourceVersion(RELEASE_7) | |
| 92 public class ElementScanner7<R, P> extends ElementScanner6<R, P> { | |
| 93 /** | |
| 94 * Constructor for concrete subclasses; uses {@code null} for the | |
| 95 * default value. | |
| 96 */ | |
| 97 protected ElementScanner7(){ | |
| 98 super(null); | |
| 99 } | |
| 100 | |
| 101 /** | |
| 102 * Constructor for concrete subclasses; uses the argument for the | |
| 103 * default value. | |
| 104 */ | |
| 105 protected ElementScanner7(R defaultValue){ | |
| 106 super(defaultValue); | |
| 107 } | |
| 108 } |
