1 | /* |
2 | * Copyright 2005-2006 Sun Microsystems, Inc. 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. Sun designates this |
8 | * particular file as subject to the "Classpath" exception as provided |
9 | * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
22 | * CA 95054 USA or visit www.sun.com if you need additional information or |
23 | * have any questions. |
24 | */ |
25 | |
26 | package javax.lang.model.util; |
27 | |
28 | import java.lang.Iterable; |
29 | import java.util.Collections; |
30 | import java.util.Iterator; |
31 | import java.util.List; |
32 | import java.util.Set; |
33 | import java.util.EnumSet; |
34 | import java.util.ArrayList; |
35 | import java.util.LinkedHashSet; |
36 | import java.util.NoSuchElementException; |
37 | |
38 | import javax.lang.model.element.*; |
39 | import javax.lang.model.type.*; |
40 | |
41 | |
42 | /** |
43 | * Filters for selecting just the elements of interest from a |
44 | * collection of elements. The returned sets and lists are new |
45 | * collections and do use the argument as a backing store. The |
46 | * methods in this class do not make any attempts to guard against |
47 | * concurrent modifications of the arguments. The returned sets and |
48 | * lists are mutable but unsafe for concurrent access. A returned set |
49 | * has the same iteration order as the argument set to a method. |
50 | * |
51 | * <p>If iterables and sets containing {@code null} are passed as |
52 | * arguments to methods in this class, a {@code NullPointerException} |
53 | * will be thrown. |
54 | * |
55 | * <p>Note that a <i>static import</i> statement can make the text of |
56 | * calls to the methods in this class more concise; for example: |
57 | * |
58 | * <blockquote><pre> |
59 | * import static javax.lang.model.util.ElementFilter.*; |
60 | * ... |
61 | * {@code List<VariableElement>} fs = fieldsIn(someClass.getEnclosedElements()); |
62 | * </pre></blockquote> |
63 | * |
64 | * @author Joseph D. Darcy |
65 | * @author Scott Seligman |
66 | * @author Peter von der Ahé |
67 | * @author Martin Buchholz |
68 | * @since 1.6 |
69 | */ |
70 | public class ElementFilter { |
71 | private ElementFilter() {} // Do not instantiate. |
72 | |
73 | private static Set<ElementKind> CONSTRUCTOR_KIND = |
74 | Collections.unmodifiableSet(EnumSet.of(ElementKind.CONSTRUCTOR)); |
75 | |
76 | private static Set<ElementKind> FIELD_KINDS = |
77 | Collections.unmodifiableSet(EnumSet.of(ElementKind.FIELD, |
78 | ElementKind.ENUM_CONSTANT)); |
79 | private static Set<ElementKind> METHOD_KIND = |
80 | Collections.unmodifiableSet(EnumSet.of(ElementKind.METHOD)); |
81 | |
82 | private static Set<ElementKind> PACKAGE_KIND = |
83 | Collections.unmodifiableSet(EnumSet.of(ElementKind.PACKAGE)); |
84 | |
85 | private static Set<ElementKind> TYPE_KINDS = |
86 | Collections.unmodifiableSet(EnumSet.of(ElementKind.CLASS, |
87 | ElementKind.ENUM, |
88 | ElementKind.INTERFACE, |
89 | ElementKind.ANNOTATION_TYPE)); |
90 | /** |
91 | * Returns a list of fields in {@code elements}. |
92 | * @return a list of fields in {@code elements} |
93 | * @param elements the elements to filter |
94 | */ |
95 | public static List<VariableElement> |
96 | fieldsIn(Iterable<? extends Element> elements) { |
97 | return listFilter(elements, FIELD_KINDS, VariableElement.class); |
98 | } |
99 | |
100 | /** |
101 | * Returns a set of fields in {@code elements}. |
102 | * @return a set of fields in {@code elements} |
103 | * @param elements the elements to filter |
104 | */ |
105 | public static Set<VariableElement> |
106 | fieldsIn(Set<? extends Element> elements) { |
107 | return setFilter(elements, FIELD_KINDS, VariableElement.class); |
108 | } |
109 | |
110 | /** |
111 | * Returns a list of constructors in {@code elements}. |
112 | * @return a list of constructors in {@code elements} |
113 | * @param elements the elements to filter |
114 | */ |
115 | public static List<ExecutableElement> |
116 | constructorsIn(Iterable<? extends Element> elements) { |
117 | return listFilter(elements, CONSTRUCTOR_KIND, ExecutableElement.class); |
118 | } |
119 | |
120 | /** |
121 | * Returns a set of constructors in {@code elements}. |
122 | * @return a set of constructors in {@code elements} |
123 | * @param elements the elements to filter |
124 | */ |
125 | public static Set<ExecutableElement> |
126 | constructorsIn(Set<? extends Element> elements) { |
127 | return setFilter(elements, CONSTRUCTOR_KIND, ExecutableElement.class); |
128 | } |
129 | |
130 | /** |
131 | * Returns a list of methods in {@code elements}. |
132 | * @return a list of methods in {@code elements} |
133 | * @param elements the elements to filter |
134 | */ |
135 | public static List<ExecutableElement> |
136 | methodsIn(Iterable<? extends Element> elements) { |
137 | return listFilter(elements, METHOD_KIND, ExecutableElement.class); |
138 | } |
139 | |
140 | /** |
141 | * Returns a set of methods in {@code elements}. |
142 | * @return a set of methods in {@code elements} |
143 | * @param elements the elements to filter |
144 | */ |
145 | public static Set<ExecutableElement> |
146 | methodsIn(Set<? extends Element> elements) { |
147 | return setFilter(elements, METHOD_KIND, ExecutableElement.class); |
148 | } |
149 | |
150 | /** |
151 | * Returns a list of types in {@code elements}. |
152 | * @return a list of types in {@code elements} |
153 | * @param elements the elements to filter |
154 | */ |
155 | public static List<TypeElement> |
156 | typesIn(Iterable<? extends Element> elements) { |
157 | return listFilter(elements, TYPE_KINDS, TypeElement.class); |
158 | } |
159 | |
160 | /** |
161 | * Returns a set of types in {@code elements}. |
162 | * @return a set of types in {@code elements} |
163 | * @param elements the elements to filter |
164 | */ |
165 | public static Set<TypeElement> |
166 | typesIn(Set<? extends Element> elements) { |
167 | return setFilter(elements, TYPE_KINDS, TypeElement.class); |
168 | } |
169 | |
170 | /** |
171 | * Returns a list of packages in {@code elements}. |
172 | * @return a list of packages in {@code elements} |
173 | * @param elements the elements to filter |
174 | */ |
175 | public static List<PackageElement> |
176 | packagesIn(Iterable<? extends Element> elements) { |
177 | return listFilter(elements, PACKAGE_KIND, PackageElement.class); |
178 | } |
179 | |
180 | /** |
181 | * Returns a set of packages in {@code elements}. |
182 | * @return a set of packages in {@code elements} |
183 | * @param elements the elements to filter |
184 | */ |
185 | public static Set<PackageElement> |
186 | packagesIn(Set<? extends Element> elements) { |
187 | return setFilter(elements, PACKAGE_KIND, PackageElement.class); |
188 | } |
189 | |
190 | // Assumes targetKinds and E are sensible. |
191 | private static <E extends Element> List<E> listFilter(Iterable<? extends Element> elements, |
192 | Set<ElementKind> targetKinds, |
193 | Class<E> clazz) { |
194 | List<E> list = new ArrayList<E>(); |
195 | for (Element e : elements) { |
196 | if (targetKinds.contains(e.getKind())) |
197 | list.add(clazz.cast(e)); |
198 | } |
199 | return list; |
200 | } |
201 | |
202 | // Assumes targetKinds and E are sensible. |
203 | private static <E extends Element> Set<E> setFilter(Set<? extends Element> elements, |
204 | Set<ElementKind> targetKinds, |
205 | Class<E> clazz) { |
206 | // Return set preserving iteration order of input set. |
207 | Set<E> set = new LinkedHashSet<E>(); |
208 | for (Element e : elements) { |
209 | if (targetKinds.contains(e.getKind())) |
210 | set.add(clazz.cast(e)); |
211 | } |
212 | return set; |
213 | } |
214 | } |