JavaCompiler


1   /*
2    * @(#)JavaCompiler.java    1.15 06/09/25
3    *
4    * Copyright 2006 Sun Microsystems, Inc. All rights reserved.
5    * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
6    */
7   
8   package javax.tools;
9   
10  import java.io.File  ;
11  import java.io.InputStream  ;
12  import java.io.Writer  ;
13  import java.nio.charset.Charset  ;
14  import java.util.List  ;
15  import java.util.Locale  ;
16  import java.util.concurrent.Callable  ;
17  import javax.annotation.processing.Processor;
18  
19  /**
20   * Interface to invoke Java&trade; programming language compilers from
21   * programs.
22   *
23   * <p>The compiler might generate diagnostics during compilation (for
24   * example, error messages).  If a diagnostic listener is provided,
25   * the diagnostics will be supplied to the listener.  If no listener
26   * is provided, the diagnostics will be formatted in an unspecified
27   * format and written to the default output, which is {@code
28   * System.err} unless otherwise specified.  Even if a diagnostic
29   * listener is supplied, some diagnostics might not fit in a {@code
30   * Diagnostic} and will be written to the default output.
31   *
32   * <p>A compiler tool has an associated standard file manager, which
33   * is the file manager that is native to the tool (or built-in).  The
34   * standard file manager can be obtained by calling {@linkplain
35   * #getStandardFileManager getStandardFileManager}.
36   *
37   * <p>A compiler tool must function with any file manager as long as
38   * any additional requirements as detailed in the methods below are
39   * met.  If no file manager is provided, the compiler tool will use a
40   * standard file manager such as the one returned by {@linkplain
41   * #getStandardFileManager getStandardFileManager}.
42   *
43   * <p>An instance implementing this interface must conform to the Java
44   * Language Specification and generate class files conforming to the
45   * Java Virtual Machine specification.  The versions of these
46   * specifications are defined in the {@linkplain Tool} interface.  
47   *
48   * Additionally, an instance of this interface supporting {@link
49   * javax.lang.model.SourceVersion#RELEASE_6 SourceVersion.RELEASE_6}
50   * or higher must also support {@linkplain javax.annotation.processing
51   * annotation processing}.
52   *
53   * <p>The compiler relies on two services: {@linkplain
54   * DiagnosticListener diagnostic listener} and {@linkplain
55   * JavaFileManager file manager}.  Although most classes and
56   * interfaces in this package defines an API for compilers (and
57   * tools in general) the interfaces {@linkplain DiagnosticListener},
58   * {@linkplain JavaFileManager}, {@linkplain FileObject}, and
59   * {@linkplain JavaFileObject} are not intended to be used in
60   * applications.  Instead these interfaces are intended to be
61   * implemented and used to provide customized services for a
62   * compiler and thus defines an SPI for compilers.
63   *
64   * <p>There are a number of classes and interfaces in this package
65   * which are designed to ease the implementation of the SPI to
66   * customize the behavior of a compiler:
67   *
68   * <dl>
69   *   <dt>{@link StandardJavaFileManager}</dt>
70   *   <dd>
71   *
72   *     Every compiler which implements this interface provides a
73   *     standard file manager for operating on regular {@linkplain
74   *     java.io.File files}.  The StandardJavaFileManager interface
75   *     defines additional methods for creating file objects from
76   *     regular files.
77   *
78   *     <p>The standard file manager serves two purposes:
79   *
80   *     <ul>
81   *       <li>basic building block for customizing how a compiler reads
82   *       and writes files</li>
83   *       <li>sharing between multiple compilation tasks</li>
84   *     </ul>
85   *
86   *     <p>Reusing a file manager can potentially reduce overhead of
87   *     scanning the file system and reading jar files.  Although there
88   *     might be no reduction in overhead, a standard file manager must
89   *     work with multiple sequential compilations making the following
90   *     example a recommended coding pattern:
91   *
92   *     <pre>
93   *       Files[] files1 = ... ; // input for first compilation task
94   *       Files[] files2 = ... ; // input for second compilation task
95   *
96   *       JavaCompiler compiler = ToolProvider.getSystemJavaCompiler();
97   *       StandardJavaFileManager fileManager = compiler.getStandardFileManager(null, null, null);
98   *
99   *       {@code Iterable<? extends JavaFileObject>} compilationUnits1 =
100  *           fileManager.getJavaFileObjectsFromFiles({@linkplain java.util.Arrays#asList Arrays.asList}(files1));
101  *       compiler.getTask(null, fileManager, null, null, null, compilationUnits1).call();
102  *
103  *       {@code Iterable<? extends JavaFileObject>} compilationUnits2 =
104  *           fileManager.getJavaFileObjects(files2); // use alternative method
105  *       // reuse the same file manager to allow caching of jar files
106  *       compiler.getTask(null, fileManager, null, null, null, compilationUnits2).call();
107  *
108  *       fileManager.close();</pre>
109  *
110  *   </dd>
111  *
112  *   <dt>{@link DiagnosticCollector}</dt>
113  *   <dd>
114  *     Used to collect diagnostics in a list, for example:
115  *     <pre>
116  *       {@code Iterable<? extends JavaFileObject>} compilationUnits = ...;
117  *       JavaCompiler compiler = ToolProvider.getSystemJavaCompiler();
118  *       {@code DiagnosticCollector<JavaFileObject> diagnostics = new DiagnosticCollector<JavaFileObject>();}
119  *       StandardJavaFileManager fileManager = compiler.getStandardFileManager(diagnostics, null, null);
120  *       compiler.getTask(null, fileManager, diagnostics, null, null, compilationUnits).call();
121  *
122  *       for (Diagnostic diagnostic : diagnostics.getDiagnostics())
123  *           System.out.format("Error on line %d in %d%n",
124  *                             diagnostic.getLineNumber()
125  *                             diagnostic.getSource().toUri());
126  *
127  *       fileManager.close();</pre>
128  *   </dd>
129  *
130  *   <dt>
131  *     {@link ForwardingJavaFileManager}, {@link ForwardingFileObject}, and
132  *     {@link ForwardingJavaFileObject}
133  *   </dt>
134  *   <dd>
135  *
136  *     Subclassing is not available for overriding the behavior of a
137  *     standard file manager as it is created by calling a method on a
138  *     compiler, not by invoking a constructor.  Instead forwarding
139  *     (or delegation) should be used.  These classes makes it easy to
140  *     forward most calls to a given file manager or file object while
141  *     allowing customizing behavior.  For example, consider how to
142  *     log all calls to {@linkplain JavaFileManager#flush}:
143  *
144  *     <pre>
145  *       final {@linkplain java.util.logging.Logger Logger} logger = ...;
146  *       {@code Iterable<? extends JavaFileObject>} compilationUnits = ...;
147  *       JavaCompiler compiler = ToolProvider.getSystemJavaCompiler();
148  *       StandardJavaFileManager stdFileManager = compiler.getStandardFileManager(null, null, null);
149  *       JavaFileManager fileManager = new ForwardingJavaFileManager(stdFileManager) {
150  *           public void flush() {
151  *               logger.entering(StandardJavaFileManager.class.getName(), "flush");
152  *               super.flush();
153  *               logger.exiting(StandardJavaFileManager.class.getName(), "flush");
154  *           }
155  *       };
156  *       compiler.getTask(null, fileManager, null, null, null, compilationUnits).call();</pre>
157  *   </dd>
158  *
159  *   <dt>{@link SimpleJavaFileObject}</dt>
160  *   <dd>
161  *
162  *     This class provides a basic file object implementation which
163  *     can be used as building block for creating file objects.  For
164  *     example, here is how to define a file object which represent
165  *     source code stored in a string:
166  *
167  *     <pre>
168  *       /**
169  *        * A file object used to represent source coming from a string.
170  *        {@code *}/
171  *       public class JavaSourceFromString extends SimpleJavaFileObject {
172  *           /**
173  *            * The source code of this "file".
174  *            {@code *}/
175  *           final String code;
176  *
177  *           /**
178  *            * Constructs a new JavaSourceFromString.
179  *            * {@code @}param name the name of the compilation unit represented by this file object
180  *            * {@code @}param code the source code for the compilation unit represented by this file object
181  *            {@code *}/
182  *           JavaSourceFromString(String name, String code) {
183  *               super({@linkplain java.net.URI#create URI.create}("string:///" + name.replace('.','/') + Kind.SOURCE.extension),
184  *                     Kind.SOURCE);
185  *               this.code = code;
186  *           }
187  *
188  *           {@code @}Override
189  *           public CharSequence getCharContent(boolean ignoreEncodingErrors) {
190  *               return code;
191  *           }
192  *       }</pre>
193  *   </dd>
194  * </dl>
195  *
196  * @author Peter von der Ah&eacute;
197  * @author Jonathan Gibbons
198  * @see DiagnosticListener
199  * @see Diagnostic
200  * @see JavaFileManager
201  * @since 1.6
202  */
203 public interface JavaCompiler extends Tool, OptionChecker {
204 
205     /**
206      * Creates a future for a compilation task with the given
207      * components and arguments.  The compilation might not have
208      * completed as described in the CompilationTask interface.
209      *
210      * <p>If a file manager is provided, it must be able to handle all
211      * locations defined in {@link StandardLocation}.
212      *
213      * @param out a Writer for additional output from the compiler;
214      * use {@code System.err} if {@code null}
215      * @param fileManager a file manager; if {@code null} use the
216      * compiler's standard filemanager
217      * @param diagnosticListener a diagnostic listener; if {@code
218      * null} use the compiler's default method for reporting
219      * diagnostics
220      * @param options compiler options, {@code null} means no options
221      * @param classes class names (for annotation processing), {@code
222      * null} means no class names
223      * @param compilationUnits the compilation units to compile, {@code
224      * null} means no compilation units
225      * @return an object representing the compilation
226      * @throws RuntimeException if an unrecoverable error
227      * occurred in a user supplied component.  The
228      * {@linkplain Throwable#getCause() cause} will be the error in
229      * user code.
230      * @throws IllegalArgumentException if any of the given
231      * compilation units are of other kind than
232      * {@linkplain JavaFileObject.Kind#SOURCE source}
233      */
234     CompilationTask getTask(Writer   out,
235                             JavaFileManager fileManager,
236                             DiagnosticListener<? super JavaFileObject> diagnosticListener,
237                             Iterable  <String  > options,
238                             Iterable  <String  > classes,
239                             Iterable  <? extends JavaFileObject> compilationUnits);
240 
241     /**
242      * Gets a new instance of the standard file manager implementation
243      * for this tool.  The file manager will use the given diagnostic
244      * listener for producing any non-fatal diagnostics.  Fatal errors
245      * will be signalled with the appropriate exceptions.
246      *
247      * <p>The standard file manager will be automatically reopened if
248      * it is accessed after calls to {@code flush} or {@code close}.
249      * The standard file manager must be usable with other tools.
250      *
251      * @param diagnosticListener a diagnostic listener for non-fatal
252      * diagnostics; if {@code null} use the compiler's default method
253      * for reporting diagnostics
254      * @param locale the locale to apply when formatting diagnostics;
255      * {@code null} means the {@linkplain Locale#getDefault() default locale}.
256      * @param charset the character set used for decoding bytes; if
257      * {@code null} use the platform default
258      * @return the standard file manager
259      */
260     StandardJavaFileManager getStandardFileManager(
261         DiagnosticListener<? super JavaFileObject> diagnosticListener,
262         Locale   locale,
263         Charset   charset);
264 
265     /**
266      * Interface representing a future for a compilation task.  The
267      * compilation task has not yet started.  To start the task, call
268      * the {@linkplain #call call} method.
269      *
270      * <p>Before calling the call method, additional aspects of the
271      * task can be configured, for example, by calling the
272      * {@linkplain #setProcessors setProcessors} method.
273      */
274     interface CompilationTask extends Callable  <Boolean  > {
275 
276         /**
277          * Sets processors (for annotation processing).  This will
278          * bypass the normal discovery mechanism.
279          *
280          * @param processors processors (for annotation processing)
281          * @throws IllegalStateException if the task has started
282          */
283         void setProcessors(Iterable  <? extends Processor> processors);
284 
285         /**
286          * Set the locale to be applied when formatting diagnostics and
287          * other localized data.
288          *
289          * @param locale the locale to apply; {@code null} means apply no
290          * locale
291          * @throws IllegalStateException if the task has started
292          */
293         void setLocale(Locale   locale);
294 
295         /**
296          * Performs this compilation task.  The compilation may only
297          * be performed once.  Subsequent calls to this method throw
298          * IllegalStateException.
299          *
300          * @return true if and only all the files compiled without errors;
301          * false otherwise
302          *
303          * @throws RuntimeException if an unrecoverable error occurred
304          * in a user-supplied component.  The
305          * {@linkplain Throwable#getCause() cause} will be the error
306          * in user code.
307          * @throws IllegalStateException if called more than once
308          */
309         Boolean   call();
310     }
311 }
312
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