JavaFileManager (Java SE 13 & JDK 13 )
Description: declaration: module: java.compiler, package: javax.tools, interface: JavaFileManager
Keywords: javax.tools.JavaFileManager interface

Module java.compiler
Package javax.tools

# Interface JavaFileManager

All Superinterfaces:
  `AutoCloseable`, `Closeable`, `Flushable`, `OptionChecker`

All Known Subinterfaces:
  `StandardJavaFileManager`

All Known Implementing Classes:
  `ForwardingJavaFileManager`

    public interface JavaFileManager
    extends Closeable, Flushable, OptionChecker

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.

Since:
  1.6
See Also:
  `JavaFileObject`, `FileObject`

- ## Nested Class Summary

  Nested Classes
  Modifier and Type | Interface | Description
  --- | --- | ---
  `static interface` | `JavaFileManager.Location` | Interface for locations of file objects.

- ## Method Summary

  Modifier and Type | Method | Description
  --- | --- | ---
  `void` | `close()` | Releases any resources opened by this file manager directly or indirectly.
  `default boolean` | `contains​(JavaFileManager.Location location, FileObject fo)` | Determines whether or not a given file object is "contained in" a specified location.
  `void` | `flush()` | Flushes any resources opened for output by this file manager directly or indirectly.
  `ClassLoader` | `getClassLoader​(JavaFileManager.Location location)` | Returns a class loader for loading plug-ins from the given package-oriented location.
  `FileObject` | `getFileForInput​(JavaFileManager.Location location, String packageName, String relativeName)` | Returns a file object for input representing the specified relative name in the specified package in the given package-oriented location.
  `FileObject` | `getFileForOutput​(JavaFileManager.Location location, String packageName, String relativeName, FileObject sibling)` | Returns a file object for output representing the specified relative name in the specified package in the given location.
  `JavaFileObject` | `getJavaFileForInput​(JavaFileManager.Location location, String className, JavaFileObject.Kind kind)` | Returns a file object for input representing the specified class of the specified kind in the given package-oriented location.
  `JavaFileObject` | `getJavaFileForOutput​(JavaFileManager.Location location, String className, JavaFileObject.Kind kind, FileObject sibling)` | Returns a file object for output representing the specified class of the specified kind in the given package-oriented location.
  `default JavaFileManager.Location` | `getLocationForModule​(JavaFileManager.Location location, String moduleName)` | Gets a location for a named module within a location, which may be either a module-oriented location or an output location.
  `default JavaFileManager.Location` | `getLocationForModule​(JavaFileManager.Location location, JavaFileObject fo)` | Gets a location for the module containing a specific file to be found within a location, which may be either a module-oriented location or an output location.
  `default <S> ServiceLoader<S>` | `getServiceLoader​(JavaFileManager.Location location, Class<S> service)` | Get a service loader for a specific service class from a given location.
  `boolean` | `handleOption​(String current, Iterator<String> remaining)` | Handles one option.
  `boolean` | `hasLocation​(JavaFileManager.Location location)` | Determines if a location is known to this file manager.
  `String` | `inferBinaryName​(JavaFileManager.Location location, JavaFileObject file)` | Infers a binary name of a file object based on a package-oriented location.
  `default String` | `inferModuleName​(JavaFileManager.Location location)` | Infer the name of the module from its location, as returned by `getLocationForModule` or `listModuleLocations`.
  `boolean` | `isSameFile​(FileObject a, FileObject b)` | Compares two file objects and return true if they represent the same underlying object.
  `Iterable<JavaFileObject>` | `list​(JavaFileManager.Location location, String packageName, Set<JavaFileObject.Kind> kinds, boolean recurse)` | Lists all file objects matching the given criteria in the given package-oriented location.
  `default Iterable<Set<JavaFileManager.Location>>` | `listLocationsForModules​(JavaFileManager.Location location)` | Lists the locations for all the modules in a module-oriented location or an output location.

  ### Methods declared in interface javax.tools.OptionChecker

  `isSupportedOption`

- ## Method Details

  - ### getClassLoader

    ClassLoader getClassLoader​(JavaFileManager.Location location)
    Returns a class loader for loading plug-ins from the given package-oriented 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
      `IllegalArgumentException` - if the location is a module-oriented location

  - ### list

    Iterable<JavaFileObject> list​(JavaFileManager.Location location, String packageName, Set<JavaFileObject.Kind> kinds, boolean recurse) throws IOException
    Lists all file objects matching the given criteria in the given package-oriented location. List file objects in "subpackages" if recurse is true.

    Note: even if the given location is unknown to this file manager, it may not return `null`. Also, an unknown location may not cause an exception.

    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
      `IllegalArgumentException` - if the location is a module-oriented location
      `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 package-oriented 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:
      `IllegalArgumentException` - if the location is a module-oriented location
      `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
    Returns a file object for input representing the specified class of the specified kind in the given package-oriented 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, or if the location is a module-oriented location
      `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
    Returns a file object for output representing the specified class of the specified kind in the given package-oriented location.

    Optionally, this file manager might consider the sibling as a hint for where to place the output. The exact semantics of this hint is unspecified. The JDK compiler, javac, for example, will place class files in the same directories as originating source files unless a class file output directory is provided. To facilitate this behavior, javac might provide the originating source file as sibling when calling this method.

    Parameters:
      `location` - a package-oriented 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, or if the location is not an output location
      `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
    Returns a file object for input representing the specified relative name in the specified package in the given package-oriented location.

    If the returned object represents a source or class file, it must be an instance of `JavaFileObject`.

    Informally, the file object returned by this method is located in the concatenation of the location, package name, and relative name. For example, to locate the properties file "resources/compiler.properties" in the package "com.sun.tools.javac" in the SOURCE_PATH location, this method might be called like so:

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

    If the call was executed on Windows, with SOURCE_PATH set to `"C:\Documents and Settings\UncleBob\src\share\classes"`, a valid result would be a file object representing the file `"C:\Documents and Settings\UncleBob\src\share\classes\com\sun\tools\javac\resources\compiler.properties"`.

    Parameters:
      `location` - a package-oriented 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, or if the location is a module-oriented location
      `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
    Returns a file object for output representing the specified relative name in the specified package in the given location.

    Optionally, this file manager might consider the sibling as a hint for where to place the output. The exact semantics of this hint is unspecified. The JDK compiler, javac, for example, will place class files in the same directories as originating source files unless a class file output directory is provided. To facilitate this behavior, javac might provide the originating source file as sibling when calling this method.

    If the returned object represents a source or class file, it must be an instance of `JavaFileObject`.

    Informally, the file object returned by this method is located in the concatenation of the location, package name, and relative name or next to the sibling argument. See `getFileForInput` for an example.

    Parameters:
      `location` - an output 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, or if the location is not an output location
      `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()`

  - ### getLocationForModule

    default JavaFileManager.Location getLocationForModule​(JavaFileManager.Location location, String moduleName) throws IOException
    Gets a location for a named module within a location, which may be either a module-oriented location or an output location. The result will be an output location if the given location is an output location, or it will be a package-oriented location.
    Implementation Requirements:
      This implementation throws `UnsupportedOperationException`.
    Parameters:
      `location` - the module-oriented location
      `moduleName` - the name of the module to be found
    Returns:
      the location for the named module
    Throws:
      `IOException` - if an I/O error occurred
      `UnsupportedOperationException` - if this operation if not supported by this file manager
      `IllegalArgumentException` - if the location is neither an output location nor a module-oriented location
    Since:
      9

  - ### getLocationForModule

    default JavaFileManager.Location getLocationForModule​(JavaFileManager.Location location, JavaFileObject fo) throws IOException
    Gets a location for the module containing a specific file to be found within a location, which may be either a module-oriented location or an output location. The result will be an output location if the given location is an output location, or it will be a package-oriented location.
    Implementation Requirements:
      This implementation throws `UnsupportedOperationException`.
    Parameters:
      `location` - the module-oriented location
      `fo` - the file
    Returns:
      the module containing the file
    Throws:
      `IOException` - if an I/O error occurred
      `UnsupportedOperationException` - if this operation if not supported by this file manager
      `IllegalArgumentException` - if the location is neither an output location nor a module-oriented location
    Since:
      9

  - ### getServiceLoader

    default <S> ServiceLoader<S> getServiceLoader​(JavaFileManager.Location location, Class<S> service) throws IOException
    Get a service loader for a specific service class from a given location. If the location is a module-oriented location, the service loader will use the service declarations in the modules found in that location. Otherwise, a service loader is created using the package-oriented location, in which case, the services are determined using the provider-configuration files in `META-INF/services`.
    Implementation Requirements:
      This implementation throws `UnsupportedOperationException`.
    Type Parameters:
      `S` - the service class
    Parameters:
      `location` - the module-oriented location
      `service` - the `Class` object of the service class
    Returns:
      a service loader for the given service class
    Throws:
      `IOException` - if an I/O error occurred
      `UnsupportedOperationException` - if this operation if not supported by this file manager
    Since:
      9

  - ### inferModuleName

    default String inferModuleName​(JavaFileManager.Location location) throws IOException
    Infer the name of the module from its location, as returned by `getLocationForModule` or `listModuleLocations`.
    Implementation Requirements:
      This implementation throws `UnsupportedOperationException`.
    Parameters:
      `location` - a package-oriented location representing a module
    Returns:
      the name of the module
    Throws:
      `IOException` - if an I/O error occurred
      `UnsupportedOperationException` - if this operation if not supported by this file manager
      `IllegalArgumentException` - if the location is not one known to this file manager
    Since:
      9

  - ### listLocationsForModules

    default Iterable<Set<JavaFileManager.Location>> listLocationsForModules​(JavaFileManager.Location location) throws IOException
    Lists the locations for all the modules in a module-oriented location or an output location. The locations that are returned will be output locations if the given location is an output, or it will be a package-oriented locations.
    Implementation Requirements:
      This implementation throws `UnsupportedOperationException`.
    Parameters:
      `location` - the module-oriented location for which to list the modules
    Returns:
      a series of sets of locations containing modules
    Throws:
      `IOException` - if an I/O error occurred
      `UnsupportedOperationException` - if this operation if not supported by this file manager
      `IllegalArgumentException` - if the location is not a module-oriented location
    Since:
      9

  - ### contains

    default boolean contains​(JavaFileManager.Location location, FileObject fo) throws IOException
    Determines whether or not a given file object is "contained in" a specified location.

    For a package-oriented location, a file object is contained in the location if there exist values for packageName and relativeName such that either of the following calls would return the `same` file object:

             getFileForInput(location, packageName, relativeName)
             getFileForOutput(location, packageName, relativeName, null)

    For a module-oriented location, a file object is contained in the location if there exists a module that may be obtained by the call:

             getLocationForModule(location, moduleName)

    such that the file object is contained in the (package-oriented) location for that module.
    Implementation Requirements:
      This implementation throws `UnsupportedOperationException`.
    Parameters:
      `location` - the location
      `fo` - the file object
    Returns:
      whether or not the file is contained in the location
    Throws:
      `IOException` - if there is a problem determining the result
      `UnsupportedOperationException` - if the method is not supported
    Since:
      9