FileDescriptor

extends Object

java.lang.Object
↳	java.io.FileDescriptor

Class Overview

The lowest-level representation of a file, device, or socket. If is often used for wrapping an operating system "handle". Some I/O classes can be queried for the FileDescriptor they are operating on, and this descriptor can subsequently be used during the instantiation of another I/O class, so that the new object will reuse it.

The FileDescriptor class also contains static fields representing the system's standard input, output and error streams. These can be used directly if desired, but it is recommended to go through System.in, System.out, and System.err streams respectively.

Applications should not create new FileDescriptors.

Summary

Constants
FileDescriptor	err	FileDescriptor representing standard error.
FileDescriptor	in	The FileDescriptor representing standard input.
FileDescriptor	out	FileDescriptor representing standard out.

Public Constructors
	FileDescriptor() Constructs a new FileDescriptor containing an invalid handle.

Public Methods
void	sync() Ensures that data which is buffered within the underlying implementation is written out to the appropriate device before returning.
boolean	valid() Indicates whether this FileDescriptor is valid.

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Inherited Methods

From class java.lang.Object

Object	clone() Creates and returns a copy of this `Object`.
boolean	equals(Object o) Compares this instance with the specified object and indicates if they are equal.
void	finalize() Is called before the object's memory is being reclaimed by the VM.
final Class<? extends Object>	getClass() Returns the unique instance of Class which represents this object's class.
int	hashCode() Returns an integer hash code for this object.
final void	notify() Causes a thread which is waiting on this object's monitor (by means of calling one of the `wait()` methods) to be woken up.
final void	notifyAll() Causes all threads which are waiting on this object's monitor (by means of calling one of the `wait()` methods) to be woken up.
String	toString() Returns a string containing a concise, human-readable description of this object.
final void	wait(long millis, int nanos) Causes the calling thread to wait until another thread calls the `notify()` or `notifyAll()` method of this object or until the specified timeout expires.
final void	wait(long millis) Causes the calling thread to wait until another thread calls the `notify()` or `notifyAll()` method of this object or until the specified timeout expires.
final void	wait() Causes the calling thread to wait until another thread calls the `notify()` or `notifyAll()` method of this object.

Constants

public static final FileDescriptor err

FileDescriptor representing standard error.

public static final FileDescriptor in

The FileDescriptor representing standard input.

public static final FileDescriptor out

FileDescriptor representing standard out.

Public Constructors

public FileDescriptor ()

Constructs a new FileDescriptor containing an invalid handle. The contained handle is usually modified by native code at a later point.

Public Methods

public void sync ()

Ensures that data which is buffered within the underlying implementation is written out to the appropriate device before returning.

Throws

SyncFailedException	when the operation fails.

public boolean valid ()

Indicates whether this FileDescriptor is valid.

Returns

true if this FileDescriptor is valid, false otherwise.

Interfaces

Classes

Exceptions