1 /*
2 * Copyright (c) 2005, 2017, 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.annotation.processing;
27
28 import java.util.Set;
29 import java.util.HashSet;
30 import java.util.Collections;
31 import java.util.Objects;
32 import javax.lang.model.element.*;
33 import javax.lang.model.SourceVersion;
34 import javax.tools.Diagnostic;
35
36 /**
37 * An abstract annotation processor designed to be a convenient
38 * superclass for most concrete annotation processors. This class
39 * examines annotation values to compute the {@linkplain
40 * #getSupportedOptions options}, {@linkplain
41 * #getSupportedAnnotationTypes annotation types}, and {@linkplain
42 * #getSupportedSourceVersion source version} supported by its
43 * subtypes.
44 *
45 * <p>The getter methods may {@linkplain Messager#printMessage issue
46 * warnings} about noteworthy conditions using the facilities available
47 * after the processor has been {@linkplain #isInitialized
48 * initialized}.
49 *
50 * <p>Subclasses are free to override the implementation and
51 * specification of any of the methods in this class as long as the
52 * general {@link javax.annotation.processing.Processor Processor}
53 * contract for that method is obeyed.
54 *
55 * @author Joseph D. Darcy
56 * @author Scott Seligman
57 * @author Peter von der Ahé
58 * @since 1.6
59 */
60 public abstract class AbstractProcessor implements Processor {
61 /**
62 * Processing environment providing by the tool framework.
63 */
64 protected ProcessingEnvironment processingEnv;
65 private boolean initialized = false;
66
67 /**
68 * Constructor for subclasses to call.
69 */
70 protected AbstractProcessor() {}
71
72 /**
73 * If the processor class is annotated with {@link
74 * SupportedOptions}, return an unmodifiable set with the same set
75 * of strings as the annotation. If the class is not so
76 * annotated, an empty set is returned.
77 *
78 * @return the options recognized by this processor, or an empty
79 * set if none
80 */
81 public Set<String> getSupportedOptions() {
82 SupportedOptions so = this.getClass().getAnnotation(SupportedOptions.class);
83 if (so == null)
84 return Collections.emptySet();
85 else
86 return arrayToSet(so.value(), false);
87 }
88
89 /**
90 * If the processor class is annotated with {@link
91 * SupportedAnnotationTypes}, return an unmodifiable set with the
92 * same set of strings as the annotation. If the class is not so
93 * annotated, an empty set is returned.
94 *
95 * If the {@linkplain ProcessingEnvironment#getSourceVersion source
96 * version} does not support modules, in other words if it is less
97 * than or equal to {@link SourceVersion#RELEASE_8 RELEASE_8},
98 * then any leading {@linkplain Processor#getSupportedAnnotationTypes
99 * module prefixes} are stripped from the names.
100 *
101 * @return the names of the annotation types supported by this
102 * processor, or an empty set if none
103 */
104 public Set<String> getSupportedAnnotationTypes() {
105 SupportedAnnotationTypes sat = this.getClass().getAnnotation(SupportedAnnotationTypes.class);
106 boolean initialized = isInitialized();
107 if (sat == null) {
108 if (initialized)
109 processingEnv.getMessager().printMessage(Diagnostic.Kind.WARNING,
110 "No SupportedAnnotationTypes annotation " +
111 "found on " + this.getClass().getName() +
112 ", returning an empty set.");
113 return Collections.emptySet();
114 } else {
115 boolean stripModulePrefixes =
116 initialized &&
117 processingEnv.getSourceVersion().compareTo(SourceVersion.RELEASE_8) <= 0;
118 return arrayToSet(sat.value(), stripModulePrefixes);
119 }
120 }
121
122 /**
123 * If the processor class is annotated with {@link
124 * SupportedSourceVersion}, return the source version in the
125 * annotation. If the class is not so annotated, {@link
126 * SourceVersion#RELEASE_6} is returned.
127 *
128 * @return the latest source version supported by this processor
129 */
130 public SourceVersion getSupportedSourceVersion() {
131 SupportedSourceVersion ssv = this.getClass().getAnnotation(SupportedSourceVersion.class);
132 SourceVersion sv = null;
133 if (ssv == null) {
134 sv = SourceVersion.RELEASE_6;
135 if (isInitialized())
136 processingEnv.getMessager().printMessage(Diagnostic.Kind.WARNING,
137 "No SupportedSourceVersion annotation " +
138 "found on " + this.getClass().getName() +
139 ", returning " + sv + ".");
140 } else
141 sv = ssv.value();
142 return sv;
143 }
144
145
146 /**
147 * Initializes the processor with the processing environment by
148 * setting the {@code processingEnv} field to the value of the
149 * {@code processingEnv} argument. An {@code
150 * IllegalStateException} will be thrown if this method is called
151 * more than once on the same object.
152 *
153 * @param processingEnv environment to access facilities the tool framework
154 * provides to the processor
155 * @throws IllegalStateException if this method is called more than once.
156 */
157 public synchronized void init(ProcessingEnvironment processingEnv) {
158 if (initialized)
159 throw new IllegalStateException("Cannot call init more than once.");
160 Objects.requireNonNull(processingEnv, "Tool provided null ProcessingEnvironment");
161
162 this.processingEnv = processingEnv;
163 initialized = true;
164 }
165
166 /**
167 * {@inheritDoc}
168 */
169 public abstract boolean process(Set<? extends TypeElement> annotations,
170 RoundEnvironment roundEnv);
171
172 /**
173 * Returns an empty iterable of completions.
174 *
175 * @param element {@inheritDoc}
176 * @param annotation {@inheritDoc}
177 * @param member {@inheritDoc}
178 * @param userText {@inheritDoc}
179 */
180 public Iterable<? extends Completion> getCompletions(Element element,
181 AnnotationMirror annotation,
182 ExecutableElement member,
183 String userText) {
184 return Collections.emptyList();
185 }
186
187 /**
188 * Returns {@code true} if this object has been {@linkplain #init
189 * initialized}, {@code false} otherwise.
190 *
191 * @return {@code true} if this object has been initialized,
192 * {@code false} otherwise.
193 */
194 protected synchronized boolean isInitialized() {
195 return initialized;
196 }
197
198 private static Set<String> arrayToSet(String[] array,
199 boolean stripModulePrefixes) {
200 assert array != null;
201 Set<String> set = new HashSet<>(array.length);
202 for (String s : array) {
203 if (stripModulePrefixes) {
204 int index = s.indexOf('/');
205 if (index != -1)
206 s = s.substring(index + 1);
207 }
208 set.add(s);
209 }
210 return Collections.unmodifiableSet(set);
211 }
212 }