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

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

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

author

aoqi

date

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

changeset 2525

2eb010b6cb22

parent 1442

fcf89720ae71

parent 0

959103a6100f

permissions

-rw-r--r--

merge

aoqi@0	1	/*
aoqi@0	2	* Copyright (c) 2005, 2012, 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 java.util.Collections;
aoqi@0	29	import java.util.List;
aoqi@0	30	import java.util.Set;
aoqi@0	31	import java.util.EnumSet;
aoqi@0	32	import java.util.ArrayList;
aoqi@0	33	import java.util.LinkedHashSet;
aoqi@0	34
aoqi@0	35	import javax.lang.model.element.*;
aoqi@0	36
aoqi@0	37
aoqi@0	38	/**
aoqi@0	39	* Filters for selecting just the elements of interest from a
aoqi@0	40	* collection of elements. The returned sets and lists are new
aoqi@0	41	* collections and do use the argument as a backing store. The
aoqi@0	42	* methods in this class do not make any attempts to guard against
aoqi@0	43	* concurrent modifications of the arguments. The returned sets and
aoqi@0	44	* lists are mutable but unsafe for concurrent access. A returned set
aoqi@0	45	* has the same iteration order as the argument set to a method.
aoqi@0	46	*
aoqi@0	47	* <p>If iterables and sets containing {@code null} are passed as
aoqi@0	48	* arguments to methods in this class, a {@code NullPointerException}
aoqi@0	49	* will be thrown.
aoqi@0	50	*
aoqi@0	51	* <p>Note that a <i>static import</i> statement can make the text of
aoqi@0	52	* calls to the methods in this class more concise; for example:
aoqi@0	53	*
aoqi@0	54	* <blockquote><pre>
aoqi@0	55	* import static javax.lang.model.util.ElementFilter.*;
aoqi@0	56	* ...
aoqi@0	57	* {@code List<VariableElement>} fs = fieldsIn(someClass.getEnclosedElements());
aoqi@0	58	* </pre></blockquote>
aoqi@0	59	*
aoqi@0	60	* @author Joseph D. Darcy
aoqi@0	61	* @author Scott Seligman
aoqi@0	62	* @author Peter von der Ah&eacute;
aoqi@0	63	* @author Martin Buchholz
aoqi@0	64	* @since 1.6
aoqi@0	65	*/
aoqi@0	66	public class ElementFilter {
aoqi@0	67	private ElementFilter() {} // Do not instantiate.
aoqi@0	68
aoqi@0	69	private static final Set<ElementKind> CONSTRUCTOR_KIND =
aoqi@0	70	Collections.unmodifiableSet(EnumSet.of(ElementKind.CONSTRUCTOR));
aoqi@0	71
aoqi@0	72	private static final Set<ElementKind> FIELD_KINDS =
aoqi@0	73	Collections.unmodifiableSet(EnumSet.of(ElementKind.FIELD,
aoqi@0	74	ElementKind.ENUM_CONSTANT));
aoqi@0	75	private static final Set<ElementKind> METHOD_KIND =
aoqi@0	76	Collections.unmodifiableSet(EnumSet.of(ElementKind.METHOD));
aoqi@0	77
aoqi@0	78	private static final Set<ElementKind> PACKAGE_KIND =
aoqi@0	79	Collections.unmodifiableSet(EnumSet.of(ElementKind.PACKAGE));
aoqi@0	80
aoqi@0	81	private static final Set<ElementKind> TYPE_KINDS =
aoqi@0	82	Collections.unmodifiableSet(EnumSet.of(ElementKind.CLASS,
aoqi@0	83	ElementKind.ENUM,
aoqi@0	84	ElementKind.INTERFACE,
aoqi@0	85	ElementKind.ANNOTATION_TYPE));
aoqi@0	86	/**
aoqi@0	87	* Returns a list of fields in {@code elements}.
aoqi@0	88	* @return a list of fields in {@code elements}
aoqi@0	89	* @param elements the elements to filter
aoqi@0	90	*/
aoqi@0	91	public static List<VariableElement>
aoqi@0	92	fieldsIn(Iterable<? extends Element> elements) {
aoqi@0	93	return listFilter(elements, FIELD_KINDS, VariableElement.class);
aoqi@0	94	}
aoqi@0	95
aoqi@0	96	/**
aoqi@0	97	* Returns a set of fields in {@code elements}.
aoqi@0	98	* @return a set of fields in {@code elements}
aoqi@0	99	* @param elements the elements to filter
aoqi@0	100	*/
aoqi@0	101	public static Set<VariableElement>
aoqi@0	102	fieldsIn(Set<? extends Element> elements) {
aoqi@0	103	return setFilter(elements, FIELD_KINDS, VariableElement.class);
aoqi@0	104	}
aoqi@0	105
aoqi@0	106	/**
aoqi@0	107	* Returns a list of constructors in {@code elements}.
aoqi@0	108	* @return a list of constructors in {@code elements}
aoqi@0	109	* @param elements the elements to filter
aoqi@0	110	*/
aoqi@0	111	public static List<ExecutableElement>
aoqi@0	112	constructorsIn(Iterable<? extends Element> elements) {
aoqi@0	113	return listFilter(elements, CONSTRUCTOR_KIND, ExecutableElement.class);
aoqi@0	114	}
aoqi@0	115
aoqi@0	116	/**
aoqi@0	117	* Returns a set of constructors in {@code elements}.
aoqi@0	118	* @return a set of constructors in {@code elements}
aoqi@0	119	* @param elements the elements to filter
aoqi@0	120	*/
aoqi@0	121	public static Set<ExecutableElement>
aoqi@0	122	constructorsIn(Set<? extends Element> elements) {
aoqi@0	123	return setFilter(elements, CONSTRUCTOR_KIND, ExecutableElement.class);
aoqi@0	124	}
aoqi@0	125
aoqi@0	126	/**
aoqi@0	127	* Returns a list of methods in {@code elements}.
aoqi@0	128	* @return a list of methods in {@code elements}
aoqi@0	129	* @param elements the elements to filter
aoqi@0	130	*/
aoqi@0	131	public static List<ExecutableElement>
aoqi@0	132	methodsIn(Iterable<? extends Element> elements) {
aoqi@0	133	return listFilter(elements, METHOD_KIND, ExecutableElement.class);
aoqi@0	134	}
aoqi@0	135
aoqi@0	136	/**
aoqi@0	137	* Returns a set of methods in {@code elements}.
aoqi@0	138	* @return a set of methods in {@code elements}
aoqi@0	139	* @param elements the elements to filter
aoqi@0	140	*/
aoqi@0	141	public static Set<ExecutableElement>
aoqi@0	142	methodsIn(Set<? extends Element> elements) {
aoqi@0	143	return setFilter(elements, METHOD_KIND, ExecutableElement.class);
aoqi@0	144	}
aoqi@0	145
aoqi@0	146	/**
aoqi@0	147	* Returns a list of types in {@code elements}.
aoqi@0	148	* @return a list of types in {@code elements}
aoqi@0	149	* @param elements the elements to filter
aoqi@0	150	*/
aoqi@0	151	public static List<TypeElement>
aoqi@0	152	typesIn(Iterable<? extends Element> elements) {
aoqi@0	153	return listFilter(elements, TYPE_KINDS, TypeElement.class);
aoqi@0	154	}
aoqi@0	155
aoqi@0	156	/**
aoqi@0	157	* Returns a set of types in {@code elements}.
aoqi@0	158	* @return a set of types in {@code elements}
aoqi@0	159	* @param elements the elements to filter
aoqi@0	160	*/
aoqi@0	161	public static Set<TypeElement>
aoqi@0	162	typesIn(Set<? extends Element> elements) {
aoqi@0	163	return setFilter(elements, TYPE_KINDS, TypeElement.class);
aoqi@0	164	}
aoqi@0	165
aoqi@0	166	/**
aoqi@0	167	* Returns a list of packages in {@code elements}.
aoqi@0	168	* @return a list of packages in {@code elements}
aoqi@0	169	* @param elements the elements to filter
aoqi@0	170	*/
aoqi@0	171	public static List<PackageElement>
aoqi@0	172	packagesIn(Iterable<? extends Element> elements) {
aoqi@0	173	return listFilter(elements, PACKAGE_KIND, PackageElement.class);
aoqi@0	174	}
aoqi@0	175
aoqi@0	176	/**
aoqi@0	177	* Returns a set of packages in {@code elements}.
aoqi@0	178	* @return a set of packages in {@code elements}
aoqi@0	179	* @param elements the elements to filter
aoqi@0	180	*/
aoqi@0	181	public static Set<PackageElement>
aoqi@0	182	packagesIn(Set<? extends Element> elements) {
aoqi@0	183	return setFilter(elements, PACKAGE_KIND, PackageElement.class);
aoqi@0	184	}
aoqi@0	185
aoqi@0	186	// Assumes targetKinds and E are sensible.
aoqi@0	187	private static <E extends Element> List<E> listFilter(Iterable<? extends Element> elements,
aoqi@0	188	Set<ElementKind> targetKinds,
aoqi@0	189	Class<E> clazz) {
aoqi@0	190	List<E> list = new ArrayList<E>();
aoqi@0	191	for (Element e : elements) {
aoqi@0	192	if (targetKinds.contains(e.getKind()))
aoqi@0	193	list.add(clazz.cast(e));
aoqi@0	194	}
aoqi@0	195	return list;
aoqi@0	196	}
aoqi@0	197
aoqi@0	198	// Assumes targetKinds and E are sensible.
aoqi@0	199	private static <E extends Element> Set<E> setFilter(Set<? extends Element> elements,
aoqi@0	200	Set<ElementKind> targetKinds,
aoqi@0	201	Class<E> clazz) {
aoqi@0	202	// Return set preserving iteration order of input set.
aoqi@0	203	Set<E> set = new LinkedHashSet<E>();
aoqi@0	204	for (Element e : elements) {
aoqi@0	205	if (targetKinds.contains(e.getKind()))
aoqi@0	206	set.add(clazz.cast(e));
aoqi@0	207	}
aoqi@0	208	return set;
aoqi@0	209	}
aoqi@0	210	}