1 /*
2 * Copyright (c) 2005, 2013, 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
29 import java.util.List;
30 import java.util.Map;
31
32 import javax.lang.model.element.*;
33 import javax.lang.model.type.*;
34
35
36 /**
37 * Utility methods for operating on program elements.
38 *
39 * <p><b>Compatibility Note:</b> Methods may be added to this interface
40 * in future releases of the platform.
41 *
42 * @author Joseph D. Darcy
43 * @author Scott Seligman
44 * @author Peter von der Ahé
45 * @see javax.annotation.processing.ProcessingEnvironment#getElementUtils
46 * @since 1.6
47 */
48 public interface Elements {
49
50 /**
51 * Returns a package given its fully qualified name.
52 *
53 * @param name fully qualified package name, or "" for an unnamed package
54 * @return the named package, or {@code null} if it cannot be found
55 */
56 PackageElement getPackageElement(CharSequence name);
57
58 /**
59 * Returns a type element given its canonical name.
60 *
61 * @param name the canonical name
62 * @return the named type element, or {@code null} if it cannot be found
63 */
64 TypeElement getTypeElement(CharSequence name);
65
66 /**
67 * Returns the values of an annotation's elements, including defaults.
68 *
69 * @see AnnotationMirror#getElementValues()
70 * @param a annotation to examine
71 * @return the values of the annotation's elements, including defaults
72 */
73 Map<? extends ExecutableElement, ? extends AnnotationValue>
74 getElementValuesWithDefaults(AnnotationMirror a);
75
76 /**
77 * Returns the text of the documentation ("Javadoc")
78 * comment of an element.
79 *
80 * <p> A documentation comment of an element is a comment that
81 * begins with "{@code /**}" , ends with a separate
82 * "<code>*/</code>", and immediately precedes the element,
83 * ignoring white space. Therefore, a documentation comment
84 * contains at least three"{@code *}" characters. The text
85 * returned for the documentation comment is a processed form of
86 * the comment as it appears in source code. The leading "{@code
87 * /**}" and trailing "<code>*/</code>" are removed. For lines
88 * of the comment starting after the initial "{@code /**}",
89 * leading white space characters are discarded as are any
90 * consecutive "{@code *}" characters appearing after the white
91 * space or starting the line. The processed lines are then
92 * concatenated together (including line terminators) and
93 * returned.
94 *
95 * @param e the element being examined
96 * @return the documentation comment of the element, or {@code null}
97 * if there is none
98 * @jls 3.6 White Space
99 */
100 String getDocComment(Element e);
101
102 /**
103 * Returns {@code true} if the element is deprecated, {@code false} otherwise.
104 *
105 * @param e the element being examined
106 * @return {@code true} if the element is deprecated, {@code false} otherwise
107 */
108 boolean isDeprecated(Element e);
109
110 /**
111 * Returns the <i>binary name</i> of a type element.
112 *
113 * @param type the type element being examined
114 * @return the binary name
115 *
116 * @see TypeElement#getQualifiedName
117 * @jls 13.1 The Form of a Binary
118 */
119 Name getBinaryName(TypeElement type);
120
121
122 /**
123 * Returns the package of an element. The package of a package is
124 * itself.
125 *
126 * @param type the element being examined
127 * @return the package of an element
128 */
129 PackageElement getPackageOf(Element type);
130
131 /**
132 * Returns all members of a type element, whether inherited or
133 * declared directly. For a class the result also includes its
134 * constructors, but not local or anonymous classes.
135 *
136 * <p>Note that elements of certain kinds can be isolated using
137 * methods in {@link ElementFilter}.
138 *
139 * @param type the type being examined
140 * @return all members of the type
141 * @see Element#getEnclosedElements
142 */
143 List<? extends Element> getAllMembers(TypeElement type);
144
145 /**
146 * Returns all annotations of an element, whether
147 * inherited or directly present.
148 *
149 * @param e the element being examined
150 * @return all annotations of the element
151 * @see Element#getAnnotationMirrors
152 */
153 List<? extends AnnotationMirror> getAllAnnotationMirrors(Element e);
154
155 /**
156 * Tests whether one type, method, or field hides another.
157 *
158 * @param hider the first element
159 * @param hidden the second element
160 * @return {@code true} if and only if the first element hides
161 * the second
162 */
163 boolean hides(Element hider, Element hidden);
164
165 /**
166 * Tests whether one method, as a member of a given type,
167 * overrides another method.
168 * When a non-abstract method overrides an abstract one, the
169 * former is also said to <i>implement</i> the latter.
170 *
171 * <p> In the simplest and most typical usage, the value of the
172 * {@code type} parameter will simply be the class or interface
173 * directly enclosing {@code overrider} (the possibly-overriding
174 * method). For example, suppose {@code m1} represents the method
175 * {@code String.hashCode} and {@code m2} represents {@code
176 * Object.hashCode}. We can then ask whether {@code m1} overrides
177 * {@code m2} within the class {@code String} (it does):
178 *
179 * <blockquote>
180 * {@code assert elements.overrides(m1, m2,
181 * elements.getTypeElement("java.lang.String")); }
182 * </blockquote>
183 *
184 * A more interesting case can be illustrated by the following example
185 * in which a method in type {@code A} does not override a
186 * like-named method in type {@code B}:
187 *
188 * <blockquote>
189 * {@code class A { public void m() {} } }<br>
190 * {@code interface B { void m(); } }<br>
191 * ...<br>
192 * {@code m1 = ...; // A.m }<br>
193 * {@code m2 = ...; // B.m }<br>
194 * {@code assert ! elements.overrides(m1, m2,
195 * elements.getTypeElement("A")); }
196 * </blockquote>
197 *
198 * When viewed as a member of a third type {@code C}, however,
199 * the method in {@code A} does override the one in {@code B}:
200 *
201 * <blockquote>
202 * {@code class C extends A implements B {} }<br>
203 * ...<br>
204 * {@code assert elements.overrides(m1, m2,
205 * elements.getTypeElement("C")); }
206 * </blockquote>
207 *
208 * @param overrider the first method, possible overrider
209 * @param overridden the second method, possibly being overridden
210 * @param type the type of which the first method is a member
211 * @return {@code true} if and only if the first method overrides
212 * the second
213 * @jls 8.4.8 Inheritance, Overriding, and Hiding
214 * @jls 9.4.1 Inheritance and Overriding
215 */
216 boolean overrides(ExecutableElement overrider, ExecutableElement overridden,
217 TypeElement type);
218
219 /**
220 * Returns the text of a <i>constant expression</i> representing a
221 * primitive value or a string.
222 * The text returned is in a form suitable for representing the value
223 * in source code.
224 *
225 * @param value a primitive value or string
226 * @return the text of a constant expression
227 * @throws IllegalArgumentException if the argument is not a primitive
228 * value or string
229 *
230 * @see VariableElement#getConstantValue()
231 */
232 String getConstantExpression(Object value);
233
234 /**
235 * Prints a representation of the elements to the given writer in
236 * the specified order. The main purpose of this method is for
237 * diagnostics. The exact format of the output is <em>not</em>
238 * specified and is subject to change.
239 *
240 * @param w the writer to print the output to
241 * @param elements the elements to print
242 */
243 void printElements(java.io.Writer w, Element... elements);
244
245 /**
246 * Return a name with the same sequence of characters as the
247 * argument.
248 *
249 * @param cs the character sequence to return as a name
250 */
251 Name getName(CharSequence cs);
252
253 /**
254 * Returns {@code true} if the type element is a functional interface, {@code false} otherwise.
255 *
256 * @param type the type element being examined
257 * @return {@code true} if the element is a functional interface, {@code false} otherwise
258 * @jls 9.8 Functional Interfaces
259 * @since 1.8
260 */
261 boolean isFunctionalInterface(TypeElement type);
262 }