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}. * *
Note that annotation processing can process both the
* compilation units of source code to be compiled, passed with
* the {@code compilationUnits} parameter, as well as class
* files, whose names are passed with the {@code classes}
* parameter.
*
* @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 names of classes to be processed by 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