The compiler might generate diagnostics during compilation (for + * example, error messages). If a diagnostic listener is provided, + * the diagnostics will be supplied to the listener. If no listener + * is provided, the diagnostics will be formatted in an unspecified + * format and written to the default output, which is {@code + * System.err} unless otherwise specified. Even if a diagnostic + * listener is supplied, some diagnostics might not fit in a {@code + * Diagnostic} and will be written to the default output. + * + *
A compiler tool has an associated standard file manager, which + * is the file manager that is native to the tool (or built-in). The + * standard file manager can be obtained by calling {@linkplain + * #getStandardFileManager getStandardFileManager}. + * + *
A compiler tool must function with any file manager as long as + * any additional requirements as detailed in the methods below are + * met. If no file manager is provided, the compiler tool will use a + * standard file manager such as the one returned by {@linkplain + * #getStandardFileManager getStandardFileManager}. + * + *
An instance implementing this interface must conform to the Java + * Language Specification and generate class files conforming to the + * Java Virtual Machine specification. The versions of these + * specifications are defined in the {@linkplain Tool} interface. + * + * Additionally, an instance of this interface supporting {@link + * javax.lang.model.SourceVersion#RELEASE_6 SourceVersion.RELEASE_6} + * or higher must also support {@linkplain javax.annotation.processing + * annotation processing}. + * + *
The compiler relies on two services: {@linkplain + * DiagnosticListener diagnostic listener} and {@linkplain + * JavaFileManager file manager}. Although most classes and + * interfaces in this package defines an API for compilers (and + * tools in general) the interfaces {@linkplain DiagnosticListener}, + * {@linkplain JavaFileManager}, {@linkplain FileObject}, and + * {@linkplain JavaFileObject} are not intended to be used in + * applications. Instead these interfaces are intended to be + * implemented and used to provide customized services for a + * compiler and thus defines an SPI for compilers. + * + *
There are a number of classes and interfaces in this package + * which are designed to ease the implementation of the SPI to + * customize the behavior of a compiler: + * + *
The standard file manager serves two purposes: + * + *
Reusing a file manager can potentially reduce overhead of + * scanning the file system and reading jar files. Although there + * might be no reduction in overhead, a standard file manager must + * work with multiple sequential compilations making the following + * example a recommended coding pattern: + * + *
+ * Files[] files1 = ... ; // input for first compilation task
+ * Files[] files2 = ... ; // input for second compilation task
+ *
+ * JavaCompiler compiler = ToolProvider.getSystemJavaCompiler();
+ * StandardJavaFileManager fileManager = compiler.getStandardFileManager(null, null, null);
+ *
+ * {@code Iterable} compilationUnits1 =
+ * fileManager.getJavaFileObjectsFromFiles({@linkplain java.util.Arrays#asList Arrays.asList}(files1));
+ * compiler.getTask(null, fileManager, null, null, null, compilationUnits1).call();
+ *
+ * {@code Iterable} compilationUnits2 =
+ * fileManager.getJavaFileObjects(files2); // use alternative method
+ * // reuse the same file manager to allow caching of jar files
+ * compiler.getTask(null, fileManager, null, null, null, compilationUnits2).call();
+ *
+ * fileManager.close();
+ *
+ *
+ * {@code Iterable} compilationUnits = ...;
+ * JavaCompiler compiler = ToolProvider.getSystemJavaCompiler();
+ * {@code DiagnosticCollector diagnostics = new DiagnosticCollector();}
+ * StandardJavaFileManager fileManager = compiler.getStandardFileManager(diagnostics, null, null);
+ * compiler.getTask(null, fileManager, diagnostics, null, null, compilationUnits).call();
+ *
+ * for (Diagnostic diagnostic : diagnostics.getDiagnostics())
+ * System.out.format("Error on line %d in %d%n",
+ * diagnostic.getLineNumber()
+ * diagnostic.getSource().toUri());
+ *
+ * fileManager.close();
+ *
+ * final {@linkplain java.util.logging.Logger Logger} logger = ...;
+ * {@code Iterable} compilationUnits = ...;
+ * JavaCompiler compiler = ToolProvider.getSystemJavaCompiler();
+ * StandardJavaFileManager stdFileManager = compiler.getStandardFileManager(null, null, null);
+ * JavaFileManager fileManager = new ForwardingJavaFileManager(stdFileManager) {
+ * public void flush() {
+ * logger.entering(StandardJavaFileManager.class.getName(), "flush");
+ * super.flush();
+ * logger.exiting(StandardJavaFileManager.class.getName(), "flush");
+ * }
+ * };
+ * compiler.getTask(null, fileManager, null, null, null, compilationUnits).call();
+ *
+ * /**
+ * * A file object used to represent source coming from a string.
+ * {@code *}/
+ * public class JavaSourceFromString extends SimpleJavaFileObject {
+ * /**
+ * * The source code of this "file".
+ * {@code *}/
+ * final String code;
+ *
+ * /**
+ * * Constructs a new JavaSourceFromString.
+ * * {@code @}param name the name of the compilation unit represented by this file object
+ * * {@code @}param code the source code for the compilation unit represented by this file object
+ * {@code *}/
+ * JavaSourceFromString(String name, String code) {
+ * super({@linkplain java.net.URI#create URI.create}("string:///" + name.replace('.','/') + Kind.SOURCE.extension),
+ * Kind.SOURCE);
+ * this.code = code;
+ * }
+ *
+ * {@code @}Override
+ * public CharSequence getCharContent(boolean ignoreEncodingErrors) {
+ * return code;
+ * }
+ * }
+ * If a file manager is provided, it must be able to handle all
+ * locations defined in {@link StandardLocation}.
+ *
+ * @param out a Writer for additional output from the compiler;
+ * use {@code System.err} if {@code null}
+ * @param fileManager a file manager; if {@code null} use the
+ * compiler's standard filemanager
+ * @param diagnosticListener a diagnostic listener; if {@code
+ * null} use the compiler's default method for reporting
+ * diagnostics
+ * @param options compiler options, {@code null} means no options
+ * @param classes class names (for annotation processing), {@code
+ * null} means no class names
+ * @param compilationUnits the compilation units to compile, {@code
+ * null} means no compilation units
+ * @return an object representing the compilation
+ * @throws RuntimeException if an unrecoverable error
+ * occurred in a user supplied component. The
+ * {@linkplain Throwable#getCause() cause} will be the error in
+ * user code.
+ * @throws IllegalArgumentException if any of the given
+ * compilation units are of other kind than
+ * {@linkplain JavaFileObject.Kind#SOURCE source}
+ */
+ CompilationTask getTask(Writer out,
+ JavaFileManager fileManager,
+ DiagnosticListener diagnosticListener,
+ Iterable The standard file manager will be automatically reopened if
+ * it is accessed after calls to {@code flush} or {@code close}.
+ * The standard file manager must be usable with other tools.
+ *
+ * @param diagnosticListener a diagnostic listener for non-fatal
+ * diagnostics; if {@code null} use the compiler's default method
+ * for reporting diagnostics
+ * @param locale the locale to apply when formatting diagnostics;
+ * {@code null} means the {@linkplain Locale#getDefault() default locale}.
+ * @param charset the character set used for decoding bytes; if
+ * {@code null} use the platform default
+ * @return the standard file manager
+ */
+ StandardJavaFileManager getStandardFileManager(
+ DiagnosticListener diagnosticListener,
+ Locale locale,
+ Charset charset);
+
+ /**
+ * Interface representing a future for a compilation task. The
+ * compilation task has not yet started. To start the task, call
+ * the {@linkplain #call call} method.
+ *
+ * Before calling the call method, additional aspects of the
+ * task can be configured, for example, by calling the
+ * {@linkplain #setProcessors setProcessors} method.
+ */
+ interface CompilationTask extends Callable