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src/share/classes/javax/lang/model/util/ElementScanner8.java@2eb010b6cb22 (annotated)

src/share/classes/javax/lang/model/util/ElementScanner8.java

Thu, 31 Aug 2017 15:17:03 +0800

author

aoqi

date

Thu, 31 Aug 2017 15:17:03 +0800

changeset 2525

2eb010b6cb22

parent 1823

b7a10bc02e7a

parent 0

959103a6100f

permissions

-rw-r--r--

merge

aoqi@0	1	/*
aoqi@0	2	* Copyright (c) 2011, 2013, Oracle and/or its affiliates. All rights reserved.
aoqi@0	3	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
aoqi@0	4	*
aoqi@0	5	* This code is free software; you can redistribute it and/or modify it
aoqi@0	6	* under the terms of the GNU General Public License version 2 only, as
aoqi@0	7	* published by the Free Software Foundation. Oracle designates this
aoqi@0	8	* particular file as subject to the "Classpath" exception as provided
aoqi@0	9	* by Oracle in the LICENSE file that accompanied this code.
aoqi@0	10	*
aoqi@0	11	* This code is distributed in the hope that it will be useful, but WITHOUT
aoqi@0	12	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
aoqi@0	13	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
aoqi@0	14	* version 2 for more details (a copy is included in the LICENSE file that
aoqi@0	15	* accompanied this code).
aoqi@0	16	*
aoqi@0	17	* You should have received a copy of the GNU General Public License version
aoqi@0	18	* 2 along with this work; if not, write to the Free Software Foundation,
aoqi@0	19	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
aoqi@0	20	*
aoqi@0	21	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
aoqi@0	22	* or visit www.oracle.com if you need additional information or have any
aoqi@0	23	* questions.
aoqi@0	24	*/
aoqi@0	25
aoqi@0	26	package javax.lang.model.util;
aoqi@0	27
aoqi@0	28	import javax.lang.model.element.*;
aoqi@0	29	import javax.annotation.processing.SupportedSourceVersion;
aoqi@0	30	import javax.lang.model.SourceVersion;
aoqi@0	31	import static javax.lang.model.SourceVersion.*;
aoqi@0	32
aoqi@0	33
aoqi@0	34	/**
aoqi@0	35	* A scanning visitor of program elements with default behavior
aoqi@0	36	* appropriate for the {@link SourceVersion#RELEASE_8 RELEASE_8}
aoqi@0	37	* source version. The <tt>visit<i>XYZ</i></tt> methods in this
aoqi@0	38	* class scan their component elements by calling {@code scan} on
aoqi@0	39	* their {@linkplain Element#getEnclosedElements enclosed elements},
aoqi@0	40	* {@linkplain ExecutableElement#getParameters parameters}, etc., as
aoqi@0	41	* indicated in the individual method specifications. A subclass can
aoqi@0	42	* control the order elements are visited by overriding the
aoqi@0	43	* <tt>visit<i>XYZ</i></tt> methods. Note that clients of a scanner
aoqi@0	44	* may get the desired behavior be invoking {@code v.scan(e, p)} rather
aoqi@0	45	* than {@code v.visit(e, p)} on the root objects of interest.
aoqi@0	46	*
aoqi@0	47	* <p>When a subclass overrides a <tt>visit<i>XYZ</i></tt> method, the
aoqi@0	48	* new method can cause the enclosed elements to be scanned in the
aoqi@0	49	* default way by calling <tt>super.visit<i>XYZ</i></tt>. In this
aoqi@0	50	* fashion, the concrete visitor can control the ordering of traversal
aoqi@0	51	* over the component elements with respect to the additional
aoqi@0	52	* processing; for example, consistently calling
aoqi@0	53	* <tt>super.visit<i>XYZ</i></tt> at the start of the overridden
aoqi@0	54	* methods will yield a preorder traversal, etc. If the component
aoqi@0	55	* elements should be traversed in some other order, instead of
aoqi@0	56	* calling <tt>super.visit<i>XYZ</i></tt>, an overriding visit method
aoqi@0	57	* should call {@code scan} with the elements in the desired order.
aoqi@0	58	*
aoqi@0	59	* <p> Methods in this class may be overridden subject to their
aoqi@0	60	* general contract. Note that annotating methods in concrete
aoqi@0	61	* subclasses with {@link java.lang.Override @Override} will help
aoqi@0	62	* ensure that methods are overridden as intended.
aoqi@0	63	*
aoqi@0	64	* <p> <b>WARNING:</b> The {@code ElementVisitor} interface
aoqi@0	65	* implemented by this class may have methods added to it in the
aoqi@0	66	* future to accommodate new, currently unknown, language structures
aoqi@0	67	* added to future versions of the Java&trade; programming language.
aoqi@0	68	* Therefore, methods whose names begin with {@code "visit"} may be
aoqi@0	69	* added to this class in the future; to avoid incompatibilities,
aoqi@0	70	* classes which extend this class should not declare any instance
aoqi@0	71	* methods with names beginning with {@code "visit"}.
aoqi@0	72	*
aoqi@0	73	* <p>When such a new visit method is added, the default
aoqi@0	74	* implementation in this class will be to call the {@link
aoqi@0	75	* #visitUnknown visitUnknown} method. A new element scanner visitor
aoqi@0	76	* class will also be introduced to correspond to the new language
aoqi@0	77	* level; this visitor will have different default behavior for the
aoqi@0	78	* visit method in question. When the new visitor is introduced, all
aoqi@0	79	* or portions of this visitor may be deprecated.
aoqi@0	80	*
aoqi@0	81	* @param <R> the return type of this visitor's methods. Use {@link
aoqi@0	82	* Void} for visitors that do not need to return results.
aoqi@0	83	* @param <P> the type of the additional parameter to this visitor's
aoqi@0	84	* methods. Use {@code Void} for visitors that do not need an
aoqi@0	85	* additional parameter.
aoqi@0	86	*
aoqi@0	87	* @see ElementScanner6
aoqi@0	88	* @see ElementScanner7
aoqi@0	89	* @since 1.8
aoqi@0	90	*/
aoqi@0	91	@SupportedSourceVersion(RELEASE_8)
aoqi@0	92	public class ElementScanner8<R, P> extends ElementScanner7<R, P> {
aoqi@0	93	/**
aoqi@0	94	* Constructor for concrete subclasses; uses {@code null} for the
aoqi@0	95	* default value.
aoqi@0	96	*/
aoqi@0	97	protected ElementScanner8(){
aoqi@0	98	super(null);
aoqi@0	99	}
aoqi@0	100
aoqi@0	101	/**
aoqi@0	102	* Constructor for concrete subclasses; uses the argument for the
aoqi@0	103	* default value.
aoqi@0	104	*
aoqi@0	105	* @param defaultValue the default value
aoqi@0	106	*/
aoqi@0	107	protected ElementScanner8(R defaultValue){
aoqi@0	108	super(defaultValue);
aoqi@0	109	}
aoqi@0	110	}