1 /*
2 * Copyright (c) 2005, 2019, 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
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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 *
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24 */
25
26 package javax.tools;
27
28 import java.io.Writer;
29 import java.nio.charset.Charset;
30 import java.util.Locale;
31 import java.util.concurrent.Callable;
32 import javax.annotation.processing.Processor;
33
34 /**
35 * Interface to invoke Java programming language compilers from
36 * programs.
37 *
38 * <p>The compiler might generate diagnostics during compilation (for
39 * example, error messages). If a diagnostic listener is provided,
40 * the diagnostics will be supplied to the listener. If no listener
41 * is provided, the diagnostics will be formatted in an unspecified
42 * format and written to the default output, which is {@code
43 * System.err} unless otherwise specified. Even if a diagnostic
44 * listener is supplied, some diagnostics might not fit in a {@code
45 * Diagnostic} and will be written to the default output.
46 *
47 * <p>A compiler tool has an associated standard file manager, which
48 * is the file manager that is native to the tool (or built-in). The
49 * standard file manager can be obtained by calling {@linkplain
50 * #getStandardFileManager getStandardFileManager}.
51 *
52 * <p>A compiler tool must function with any file manager as long as
53 * any additional requirements as detailed in the methods below are
54 * met. If no file manager is provided, the compiler tool will use a
55 * standard file manager such as the one returned by {@linkplain
56 * #getStandardFileManager getStandardFileManager}.
57 *
58 * <p>An instance implementing this interface must conform to
59 * <cite>The Java Language Specification</cite>
60 * and generate class files conforming to
61 * <cite>The Java Virtual Machine Specification</cite>.
62 * The versions of these
63 * specifications are defined in the {@linkplain Tool} interface.
64 *
65 * Additionally, an instance of this interface supporting {@link
66 * javax.lang.model.SourceVersion#RELEASE_6 SourceVersion.RELEASE_6}
67 * or higher must also support {@linkplain javax.annotation.processing
68 * annotation processing}.
69 *
70 * <p>The compiler relies on two services: {@linkplain
71 * DiagnosticListener diagnostic listener} and {@linkplain
72 * JavaFileManager file manager}. Although most classes and
73 * interfaces in this package defines an API for compilers (and
74 * tools in general) the interfaces {@linkplain DiagnosticListener},
75 * {@linkplain JavaFileManager}, {@linkplain FileObject}, and
76 * {@linkplain JavaFileObject} are not intended to be used in
77 * applications. Instead these interfaces are intended to be
78 * implemented and used to provide customized services for a
79 * compiler and thus defines an SPI for compilers.
80 *
81 * <p>There are a number of classes and interfaces in this package
82 * which are designed to ease the implementation of the SPI to
83 * customize the behavior of a compiler:
84 *
85 * <dl>
86 * <dt>{@link StandardJavaFileManager}</dt>
87 * <dd>
88 *
89 * Every compiler which implements this interface provides a
90 * standard file manager for operating on regular {@linkplain
91 * java.io.File files}. The StandardJavaFileManager interface
92 * defines additional methods for creating file objects from
93 * regular files.
94 *
95 * <p>The standard file manager serves two purposes:
96 *
97 * <ul>
98 * <li>basic building block for customizing how a compiler reads
99 * and writes files</li>
100 * <li>sharing between multiple compilation tasks</li>
101 * </ul>
102 *
103 * <p>Reusing a file manager can potentially reduce overhead of
104 * scanning the file system and reading jar files. Although there
105 * might be no reduction in overhead, a standard file manager must
106 * work with multiple sequential compilations making the following
107 * example a recommended coding pattern:
108 *
109 * <pre>
110 * File[] files1 = ... ; // input for first compilation task
111 * File[] files2 = ... ; // input for second compilation task
112 *
113 * JavaCompiler compiler = ToolProvider.getSystemJavaCompiler();
114 * StandardJavaFileManager fileManager = compiler.getStandardFileManager(null, null, null);
115 *
116 * {@code Iterable<? extends JavaFileObject>} compilationUnits1 =
117 * fileManager.getJavaFileObjectsFromFiles({@linkplain java.util.Arrays#asList Arrays.asList}(files1));
118 * compiler.getTask(null, fileManager, null, null, null, compilationUnits1).call();
119 *
120 * {@code Iterable<? extends JavaFileObject>} compilationUnits2 =
121 * fileManager.getJavaFileObjects(files2); // use alternative method
122 * // reuse the same file manager to allow caching of jar files
123 * compiler.getTask(null, fileManager, null, null, null, compilationUnits2).call();
124 *
125 * fileManager.close();</pre>
126 *
127 * </dd>
128 *
129 * <dt>{@link DiagnosticCollector}</dt>
130 * <dd>
131 * Used to collect diagnostics in a list, for example:
132 * <pre>
133 * {@code Iterable<? extends JavaFileObject>} compilationUnits = ...;
134 * JavaCompiler compiler = ToolProvider.getSystemJavaCompiler();
135 * {@code DiagnosticCollector<JavaFileObject> diagnostics = new DiagnosticCollector<JavaFileObject>();}
136 * StandardJavaFileManager fileManager = compiler.getStandardFileManager(diagnostics, null, null);
137 * compiler.getTask(null, fileManager, diagnostics, null, null, compilationUnits).call();
138 *
139 * for ({@code Diagnostic<? extends JavaFileObject>} diagnostic : diagnostics.getDiagnostics())
140 * System.out.format("Error on line %d in %s%n",
141 * diagnostic.getLineNumber(),
142 * diagnostic.getSource().toUri());
143 *
144 * fileManager.close();</pre>
145 * </dd>
146 *
147 * <dt>
148 * {@link ForwardingJavaFileManager}, {@link ForwardingFileObject}, and
149 * {@link ForwardingJavaFileObject}
150 * </dt>
151 * <dd>
152 *
153 * Subclassing is not available for overriding the behavior of a
154 * standard file manager as it is created by calling a method on a
155 * compiler, not by invoking a constructor. Instead forwarding
156 * (or delegation) should be used. These classes makes it easy to
157 * forward most calls to a given file manager or file object while
158 * allowing customizing behavior. For example, consider how to
159 * log all calls to {@linkplain JavaFileManager#flush}:
160 *
161 * <pre>
162 * final Logger logger = ...;
163 * {@code Iterable<? extends JavaFileObject>} compilationUnits = ...;
164 * JavaCompiler compiler = ToolProvider.getSystemJavaCompiler();
165 * StandardJavaFileManager stdFileManager = compiler.getStandardFileManager(null, null, null);
166 * JavaFileManager fileManager = new ForwardingJavaFileManager(stdFileManager) {
167 * public void flush() throws IOException {
168 * logger.entering(StandardJavaFileManager.class.getName(), "flush");
169 * super.flush();
170 * logger.exiting(StandardJavaFileManager.class.getName(), "flush");
171 * }
172 * };
173 * compiler.getTask(null, fileManager, null, null, null, compilationUnits).call();</pre>
174 * </dd>
175 *
176 * <dt>{@link SimpleJavaFileObject}</dt>
177 * <dd>
178 *
179 * This class provides a basic file object implementation which
180 * can be used as building block for creating file objects. For
181 * example, here is how to define a file object which represent
182 * source code stored in a string:
183 *
184 * <pre>
185 * /**
186 * * A file object used to represent source coming from a string.
187 * {@code *}/
188 * public class JavaSourceFromString extends SimpleJavaFileObject {
189 * /**
190 * * The source code of this "file".
191 * {@code *}/
192 * final String code;
193 *
194 * /**
195 * * Constructs a new JavaSourceFromString.
196 * * {@code @}param name the name of the compilation unit represented by this file object
197 * * {@code @}param code the source code for the compilation unit represented by this file object
198 * {@code *}/
199 * JavaSourceFromString(String name, String code) {
200 * super({@linkplain java.net.URI#create URI.create}("string:///" + name.replace('.','/') + Kind.SOURCE.extension),
201 * Kind.SOURCE);
202 * this.code = code;
203 * }
204 *
205 * {@code @}Override
206 * public CharSequence getCharContent(boolean ignoreEncodingErrors) {
207 * return code;
208 * }
209 * }</pre>
210 * </dd>
211 * </dl>
212 *
213 * @author Peter von der Ahé
214 * @author Jonathan Gibbons
215 * @see DiagnosticListener
216 * @see Diagnostic
217 * @see JavaFileManager
218 * @since 1.6
219 */
220 public interface JavaCompiler extends Tool, OptionChecker {
221
222 /**
223 * Creates a future for a compilation task with the given
224 * components and arguments. The compilation might not have
225 * completed as described in the CompilationTask interface.
226 *
227 * <p>If a file manager is provided, it must be able to handle all
228 * locations defined in {@link StandardLocation}.
229 *
230 * <p>Note that annotation processing can process both the
231 * compilation units of source code to be compiled, passed with
232 * the {@code compilationUnits} parameter, as well as class
233 * files, whose names are passed with the {@code classes}
234 * parameter.
235 *
236 * @param out a Writer for additional output from the compiler;
237 * use {@code System.err} if {@code null}
238 * @param fileManager a file manager; if {@code null} use the
239 * compiler's standard file manager
240 * @param diagnosticListener a diagnostic listener; if {@code
241 * null} use the compiler's default method for reporting
242 * diagnostics
243 * @param options compiler options, {@code null} means no options
244 * @param classes names of classes to be processed by annotation
245 * processing, {@code null} means no class names
246 * @param compilationUnits the compilation units to compile, {@code
247 * null} means no compilation units
248 * @return an object representing the compilation
249 * @throws RuntimeException if an unrecoverable error
250 * occurred in a user supplied component. The
251 * {@linkplain Throwable#getCause() cause} will be the error in
252 * user code.
253 * @throws IllegalArgumentException if any of the options are invalid,
254 * or if any of the given compilation units are of other kind than
255 * {@linkplain JavaFileObject.Kind#SOURCE source}
256 */
257 CompilationTask getTask(Writer out,
258 JavaFileManager fileManager,
259 DiagnosticListener<? super JavaFileObject> diagnosticListener,
260 Iterable<String> options,
261 Iterable<String> classes,
262 Iterable<? extends JavaFileObject> compilationUnits);
263
264 /**
265 * Returns a new instance of the standard file manager implementation
266 * for this tool. The file manager will use the given diagnostic
267 * listener for producing any non-fatal diagnostics. Fatal errors
268 * will be signaled with the appropriate exceptions.
269 *
270 * <p>The standard file manager will be automatically reopened if
271 * it is accessed after calls to {@code flush} or {@code close}.
272 * The standard file manager must be usable with other tools.
273 *
274 * @param diagnosticListener a diagnostic listener for non-fatal
275 * diagnostics; if {@code null} use the compiler's default method
276 * for reporting diagnostics
277 * @param locale the locale to apply when formatting diagnostics;
278 * {@code null} means the {@linkplain Locale#getDefault() default locale}.
279 * @param charset the character set used for decoding bytes; if
280 * {@code null} use the platform default
281 * @return the standard file manager
282 */
283 StandardJavaFileManager getStandardFileManager(
284 DiagnosticListener<? super JavaFileObject> diagnosticListener,
285 Locale locale,
286 Charset charset);
287
288 /**
289 * Interface representing a future for a compilation task. The
290 * compilation task has not yet started. To start the task, call
291 * the {@linkplain #call call} method.
292 *
293 * <p>Before calling the {@code call} method, additional aspects of the
294 * task can be configured, for example, by calling the
295 * {@linkplain #setProcessors setProcessors} method.
296 */
297 interface CompilationTask extends Callable<Boolean> {
298 /**
299 * Adds root modules to be taken into account during module
300 * resolution.
301 * Invalid module names may cause either
302 * {@code IllegalArgumentException} to be thrown,
303 * or diagnostics to be reported when the task is started.
304 * @param moduleNames the names of the root modules
305 * @throws IllegalArgumentException may be thrown for some
306 * invalid module names
307 * @throws IllegalStateException if the task has started
308 * @since 9
309 */
310 void addModules(Iterable<String> moduleNames);
311
312 /**
313 * Sets processors (for annotation processing). This will
314 * bypass the normal discovery mechanism.
315 *
316 * @param processors processors (for annotation processing)
317 * @throws IllegalStateException if the task has started
318 */
319 void setProcessors(Iterable<? extends Processor> processors);
320
321 /**
322 * Sets the locale to be applied when formatting diagnostics and
323 * other localized data.
324 *
325 * @param locale the locale to apply; {@code null} means apply no
326 * locale
327 * @throws IllegalStateException if the task has started
328 */
329 void setLocale(Locale locale);
330
331 /**
332 * Performs this compilation task. The compilation may only
333 * be performed once. Subsequent calls to this method throw
334 * {@code IllegalStateException}.
335 *
336 * @return true if and only all the files compiled without errors;
337 * false otherwise
338 *
339 * @throws RuntimeException if an unrecoverable error occurred
340 * in a user-supplied component. The
341 * {@linkplain Throwable#getCause() cause} will be the error
342 * in user code.
343 * @throws IllegalStateException if called more than once
344 */
345 @Override
346 Boolean call();
347 }
348 }