Interface JavaFileManager

File manager for tools operating on Java™ programming language source and class files. In this context, file means an abstraction of regular files and other sources of data.

When constructing new JavaFileObjects, the file manager must determine where to create them. For example, if a file manager manages regular files on a file system, it would most likely have a current/working directory to use as default location when creating or finding files. A number of hints can be provided to a file manager as to where to create files. Any file manager might choose to ignore these hints.

Some methods in this interface use class names. Such class names must be given in the Java Virtual Machine internal form of fully qualified class and interface names. For convenience '.' and '/' are interchangeable. The internal form is defined in chapter four of The Java™ Virtual Machine Specification.

Discussion: this means that the names "java/lang.package-info", "java/lang/package-info", "java.lang.package-info", are valid and equivalent. Compare to binary name as defined in The Java™ Language Specification, section 13.1 "The Form of a Binary".

The case of names is significant. All names should be treated as case-sensitive. For example, some file systems have case-insensitive, case-aware file names. File objects representing such files should take care to preserve case by using File.getCanonicalFile() or similar means. If the system is not case-aware, file objects must use other means to preserve case.

Relative names: some methods in this interface use relative names. A relative name is a non-null, non-empty sequence of path segments separated by '/'. '.' or '..' are invalid path segments. A valid relative name must match the "path-rootless" rule of RFC 3986, section 3.3. Informally, this should be true:

URI.create(relativeName).normalize().getPath().equals(relativeName)

All methods in this interface might throw a SecurityException.

An object of this interface is not required to support multi-threaded access, that is, be synchronized. However, it must support concurrent access to different file objects created by this object.

Implementation note: a consequence of this requirement is that a trivial implementation of output to a JarOutputStream is not a sufficient implementation. That is, rather than creating a JavaFileObject that returns the JarOutputStream directly, the contents must be cached until closed and then written to the JarOutputStream.

Unless explicitly allowed, all methods in this interface might throw a NullPointerException if given a null argument.

Methods

getClassLoader

ClassLoader getClassLoader(JavaFileManager.Location location)

Gets a class loader for loading plug-ins from the given location. For example, to load annotation processors, a compiler will request a class loader for the ANNOTATION_PROCESSOR_PATH location.

Parameters:

location - a location

Returns:

a class loader for the given location; or null if loading plug-ins from the given location is disabled or if the location is not known

Throws:

SecurityException - if a class loader can not be created in the current security context

IllegalStateException - if close() has been called and this file manager cannot be reopened

list

Iterable<JavaFileObject> list(JavaFileManager.Location location,
                              String packageName,
                              Set<JavaFileObject.Kind> kinds,
                              boolean recurse)
                       throws IOException

Parameters:

location - a location

packageName - a package name

kinds - return objects only of these kinds

recurse - if true include "subpackages"

Returns:

an Iterable of file objects matching the given criteria

Throws:

IOException - if an I/O error occurred, or if close() has been called and this file manager cannot be reopened

IllegalStateException - if close() has been called and this file manager cannot be reopened

inferBinaryName

String inferBinaryName(JavaFileManager.Location location,
                       JavaFileObject file)

Infers a binary name of a file object based on a location. The binary name returned might not be a valid binary name according to The Java™ Language Specification.

Parameters:

location - a location

file - a file object

Returns:

a binary name or null the file object is not found in the given location

Throws:

IllegalStateException - if close() has been called and this file manager cannot be reopened

isSameFile

boolean isSameFile(FileObject a,
                   FileObject b)

Compares two file objects and return true if they represent the same underlying object.

Parameters:

a - a file object

b - a file object

Returns:

true if the given file objects represent the same underlying object

Throws:

IllegalArgumentException - if either of the arguments were created with another file manager and this file manager does not support foreign file objects

handleOption

boolean handleOption(String current,
                     Iterator<String> remaining)

Handles one option. If current is an option to this file manager it will consume any arguments to that option from remaining and return true, otherwise return false.

Parameters:

current - current option

remaining - remaining options

Returns:

true if this option was handled by this file manager, false otherwise

Throws:

IllegalArgumentException - if this option to this file manager is used incorrectly

IllegalStateException - if close() has been called and this file manager cannot be reopened

hasLocation

boolean hasLocation(JavaFileManager.Location location)

Determines if a location is known to this file manager.

Parameters:

location - a location

Returns:

true if the location is known

getJavaFileForInput

JavaFileObject getJavaFileForInput(JavaFileManager.Location location,
                                   String className,
                                   JavaFileObject.Kind kind)
                            throws IOException

Gets a file object for input representing the specified class of the specified kind in the given location.

Parameters:

location - a location

className - the name of a class

kind - the kind of file, must be one of SOURCE or CLASS

Returns:

a file object, might return null if the file does not exist

Throws:

IllegalArgumentException - if the location is not known to this file manager and the file manager does not support unknown locations, or if the kind is not valid

IOException - if an I/O error occurred, or if close() has been called and this file manager cannot be reopened

IllegalStateException - if close() has been called and this file manager cannot be reopened

getJavaFileForOutput

JavaFileObject getJavaFileForOutput(JavaFileManager.Location location,
                                    String className,
                                    JavaFileObject.Kind kind,
                                    FileObject sibling)
                             throws IOException

Parameters:

location - a location

className - the name of a class

kind - the kind of file, must be one of SOURCE or CLASS

sibling - a file object to be used as hint for placement; might be null

Returns:

a file object for output

Throws:

IllegalArgumentException - if sibling is not known to this file manager, or if the location is not known to this file manager and the file manager does not support unknown locations, or if the kind is not valid

IOException - if an I/O error occurred, or if close() has been called and this file manager cannot be reopened

IllegalStateException - close() has been called and this file manager cannot be reopened

getFileForInput

FileObject getFileForInput(JavaFileManager.Location location,
                           String packageName,
                           String relativeName)
                    throws IOException

getFileForInput(SOURCE_PATH, "com.sun.tools.javac", "resources/compiler.properties");

Parameters:

location - a location

packageName - a package name

relativeName - a relative name

Returns:

a file object, might return null if the file does not exist

Throws:

IllegalArgumentException - if the location is not known to this file manager and the file manager does not support unknown locations, or if relativeName is not valid

IOException - if an I/O error occurred, or if close() has been called and this file manager cannot be reopened

IllegalStateException - if close() has been called and this file manager cannot be reopened

getFileForOutput

FileObject getFileForOutput(JavaFileManager.Location location,
                            String packageName,
                            String relativeName,
                            FileObject sibling)
                     throws IOException

Parameters:

location - a location

packageName - a package name

relativeName - a relative name

sibling - a file object to be used as hint for placement; might be null

Returns:

a file object

Throws:

IllegalArgumentException - if sibling is not known to this file manager, or if the location is not known to this file manager and the file manager does not support unknown locations, or if relativeName is not valid

IOException - if an I/O error occurred, or if close() has been called and this file manager cannot be reopened

IllegalStateException - if close() has been called and this file manager cannot be reopened

flush

void flush()
    throws IOException

Flushes any resources opened for output by this file manager directly or indirectly. Flushing a closed file manager has no effect.

Specified by:

flush in interface Flushable

Throws:

IOException - if an I/O error occurred

See Also:

close()

close

void close()
    throws IOException

Releases any resources opened by this file manager directly or indirectly. This might render this file manager useless and the effect of subsequent calls to methods on this object or any objects obtained through this object is undefined unless explicitly allowed. However, closing a file manager which has already been closed has no effect.

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Closeable

Throws:

IOException - if an I/O error occurred

See Also:

flush()