| JavaTM 2 Platform Std. Ed. v1.6.0
javax.tools
Interface JavaCompiler
- All Superinterfaces:
- OptionChecker, Tool
public interface JavaCompiler - extends Tool, OptionChecker
Interface to invoke Java™ programming language compilers from
programs.
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 System.err unless otherwise specified. Even if a diagnostic
listener is supplied, some diagnostics might not fit in a 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 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 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 Tool interface.
Additionally, an instance of this interface supporting SourceVersion.RELEASE_6
or higher must also support annotation processing.
The compiler relies on two services: diagnostic listener and file manager. Although most classes and
interfaces in this package defines an API for compilers (and
tools in general) the interfaces DiagnosticListener,
JavaFileManager, FileObject, and
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:
StandardJavaFileManager-
Every compiler which implements this interface provides a
standard file manager for operating on regular files. The StandardJavaFileManager interface
defines additional methods for creating file objects from
regular files.
The standard file manager serves two purposes:
- basic building block for customizing how a compiler reads
and writes files
- sharing between multiple compilation tasks
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);
Iterable<? extends JavaFileObject> compilationUnits1 =
fileManager.getJavaFileObjectsFromFiles(Arrays.asList(files1));
compiler.getTask(null, fileManager, null, null, null, compilationUnits1).call();
Iterable<? extends JavaFileObject> 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();
DiagnosticCollector-
Used to collect diagnostics in a list, for example:
Iterable<? extends JavaFileObject> compilationUnits = ...;
JavaCompiler compiler = ToolProvider.getSystemJavaCompiler();
DiagnosticCollector<JavaFileObject> diagnostics = new DiagnosticCollector<JavaFileObject>();
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();
-
ForwardingJavaFileManager, ForwardingFileObject, and
ForwardingJavaFileObject
-
Subclassing is not available for overriding the behavior of a
standard file manager as it is created by calling a method on a
compiler, not by invoking a constructor. Instead forwarding
(or delegation) should be used. These classes makes it easy to
forward most calls to a given file manager or file object while
allowing customizing behavior. For example, consider how to
log all calls to JavaFileManager.flush():
final Logger logger = ...;
Iterable<? extends JavaFileObject> 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();
SimpleJavaFileObject-
This class provides a basic file object implementation which
can be used as building block for creating file objects. For
example, here is how to define a file object which represent
source code stored in a string:
/**
* A file object used to represent source coming from a string.
*/
public class JavaSourceFromString extends SimpleJavaFileObject {
/**
* The source code of this "file".
*/
final String code;
/**
* Constructs a new JavaSourceFromString.
* @param name the name of the compilation unit represented by this file object
* @param code the source code for the compilation unit represented by this file object
*/
JavaSourceFromString(String name, String code) {
super(URI.create("string:///" + name.replace('.','/') + Kind.SOURCE.extension),
Kind.SOURCE);
this.code = code;
}
@Override
public CharSequence getCharContent(boolean ignoreEncodingErrors) {
return code;
}
}
- Since:
- 1.6
- See Also:
DiagnosticListener,
Diagnostic,
JavaFileManager
getTask
JavaCompiler.CompilationTask getTask(Writer out,
JavaFileManager fileManager,
DiagnosticListener<? super JavaFileObject> diagnosticListener,
Iterable<String> options,
Iterable<String> classes,
Iterable<? extends JavaFileObject> compilationUnits)
- Creates a future for a compilation task with the given
components and arguments. The compilation might not have
completed as described in the CompilationTask interface.
If a file manager is provided, it must be able to handle all
locations defined in StandardLocation.
- Parameters:
out - a Writer for additional output from the compiler;
use System.err if nullfileManager - a file manager; if null use the
compiler's standard filemanagerdiagnosticListener - a diagnostic listener; if null use the compiler's default method for reporting
diagnosticsoptions - compiler options, null means no optionsclasses - class names (for annotation processing), null means no class namescompilationUnits - the compilation units to compile, null means no compilation units
- Returns:
- an object representing the compilation
- Throws:
RuntimeException - if an unrecoverable error
occurred in a user supplied component. The
cause will be the error in
user code.
IllegalArgumentException - if any of the given
compilation units are of other kind than
source
getStandardFileManager
StandardJavaFileManager getStandardFileManager(DiagnosticListener<? super JavaFileObject> diagnosticListener,
Locale locale,
Charset charset)
- Gets a new instance of the standard file manager implementation
for this tool. The file manager will use the given diagnostic
listener for producing any non-fatal diagnostics. Fatal errors
will be signalled with the appropriate exceptions.
The standard file manager will be automatically reopened if
it is accessed after calls to flush or close.
The standard file manager must be usable with other tools.
- Parameters:
diagnosticListener - a diagnostic listener for non-fatal
diagnostics; if null use the compiler's default method
for reporting diagnosticslocale - the locale to apply when formatting diagnostics;
null means the default locale.charset - the character set used for decoding bytes; if
null use the platform default
- Returns:
- the standard file manager
Copyright 2003 Sun Microsystems, Inc. All rights reserved
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