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.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 annotations}, 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());
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 * @return the names of the annotation types supported by this
96 * processor, or an empty set if none
97 */
98 public Set<String> getSupportedAnnotationTypes() {
99 SupportedAnnotationTypes sat = this.getClass().getAnnotation(SupportedAnnotationTypes.class);
100 if (sat == null) {
101 if (isInitialized())
102 processingEnv.getMessager().printMessage(Diagnostic.Kind.WARNING,
103 "No SupportedAnnotationTypes annotation " +
104 "found on " + this.getClass().getName() +
105 ", returning an empty set.");
106 return Collections.emptySet();
107 }
108 else
109 return arrayToSet(sat.value());
110 }
111
112 /**
113 * If the processor class is annotated with {@link
114 * SupportedSourceVersion}, return the source version in the
115 * annotation. If the class is not so annotated, {@link
116 * SourceVersion#RELEASE_6} is returned.
117 *
118 * @return the latest source version supported by this processor
119 */
120 public SourceVersion getSupportedSourceVersion() {
121 SupportedSourceVersion ssv = this.getClass().getAnnotation(SupportedSourceVersion.class);
122 SourceVersion sv = null;
123 if (ssv == null) {
124 sv = SourceVersion.RELEASE_6;
125 if (isInitialized())
126 processingEnv.getMessager().printMessage(Diagnostic.Kind.WARNING,
127 "No SupportedSourceVersion annotation " +
128 "found on " + this.getClass().getName() +
129 ", returning " + sv + ".");
130 } else
131 sv = ssv.value();
132 return sv;
133 }
134
135
136 /**
137 * Initializes the processor with the processing environment by
138 * setting the {@code processingEnv} field to the value of the
139 * {@code processingEnv} argument. An {@code
140 * IllegalStateException} will be thrown if this method is called
141 * more than once on the same object.
142 *
143 * @param processingEnv environment to access facilities the tool framework
144 * provides to the processor
145 * @throws IllegalStateException if this method is called more than once.
146 */
147 public synchronized void init(ProcessingEnvironment processingEnv) {
148 if (initialized)
149 throw new IllegalStateException("Cannot call init more than once.");
150 Objects.requireNonNull(processingEnv, "Tool provided null ProcessingEnvironment");
151
152 this.processingEnv = processingEnv;
153 initialized = true;
154 }
155
156 /**
157 * {@inheritDoc}
158 */
159 public abstract boolean process(Set<? extends TypeElement> annotations,
160 RoundEnvironment roundEnv);
161
162 /**
163 * Returns an empty iterable of completions.
164 *
165 * @param element {@inheritDoc}
166 * @param annotation {@inheritDoc}
167 * @param member {@inheritDoc}
168 * @param userText {@inheritDoc}
169 */
170 public Iterable<? extends Completion> getCompletions(Element element,
171 AnnotationMirror annotation,
172 ExecutableElement member,
173 String userText) {
174 return Collections.emptyList();
175 }
176
177 /**
178 * Returns {@code true} if this object has been {@linkplain #init
179 * initialized}, {@code false} otherwise.
180 *
181 * @return {@code true} if this object has been initialized,
182 * {@code false} otherwise.
183 */
184 protected synchronized boolean isInitialized() {
185 return initialized;
186 }
187
188 private static Set<String> arrayToSet(String[] array) {
189 assert array != null;
190 Set<String> set = new HashSet<String>(array.length);
191 for (String s : array)
192 set.add(s);
193 return Collections.unmodifiableSet(set);
194 }
195 }