Added in API level 1

Summary: Methods | Inherited Methods

Channels

public final class Channels
extends Object

java.lang.Object
↳	java.nio.channels.Channels

---

Utility methods for channels and streams.

This class defines static methods that support the interoperation of the stream classes of the java.io package with the channel classes of this package.

Summary

Public methods
static ReadableByteChannel	newChannel(InputStream in) Constructs a channel that reads bytes from the given stream.
static WritableByteChannel	newChannel(OutputStream out) Constructs a channel that writes bytes to the given stream.
static InputStream	newInputStream(ReadableByteChannel ch) Constructs a stream that reads bytes from the given channel.
static InputStream	newInputStream(AsynchronousByteChannel ch) Constructs a stream that reads bytes from the given channel.
static OutputStream	newOutputStream(AsynchronousByteChannel ch) Constructs a stream that writes bytes to the given channel.
static OutputStream	newOutputStream(WritableByteChannel ch) Constructs a stream that writes bytes to the given channel.
static Reader	newReader(ReadableByteChannel ch, Charset charset) Constructs a reader that decodes bytes from the given channel according to the given charset.
static Reader	newReader(ReadableByteChannel ch, CharsetDecoder dec, int minBufferCap) Constructs a reader that decodes bytes from the given channel using the given decoder.
static Reader	newReader(ReadableByteChannel ch, String csName) Constructs a reader that decodes bytes from the given channel according to the named charset.
static Writer	newWriter(WritableByteChannel ch, CharsetEncoder enc, int minBufferCap) Constructs a writer that encodes characters using the given encoder and writes the resulting bytes to the given channel.
static Writer	newWriter(WritableByteChannel ch, Charset charset) Constructs a writer that encodes characters according to the given charset and writes the resulting bytes to the given channel.
static Writer	newWriter(WritableByteChannel ch, String csName) Constructs a writer that encodes characters according to the named charset and writes the resulting bytes to the given channel.

Inherited methods

From class java.lang.Object Object clone() Creates and returns a copy of this object. boolean equals(Object obj) Indicates whether some other object is "equal to" this one. void finalize() Called by the garbage collector on an object when garbage collection determines that there are no more references to the object. final Class<?> getClass() Returns the runtime class of this Object. int hashCode() Returns a hash code value for the object. final void notify() Wakes up a single thread that is waiting on this object's monitor. final void notifyAll() Wakes up all threads that are waiting on this object's monitor. String toString() Returns a string representation of the object. final void wait(long timeoutMillis, int nanos) Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed. final void wait(long timeoutMillis) Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed. final void wait() Causes the current thread to wait until it is awakened, typically by being notified or interrupted.

Public methods

newChannel

Added in API level 1

public static ReadableByteChannel newChannel (InputStream in)

Constructs a channel that reads bytes from the given stream.

The resulting channel will not be buffered; it will simply redirect its I/O operations to the given stream. Closing the channel will in turn cause the stream to be closed.

Parameters
in	InputStream: The stream from which bytes are to be read

Returns
ReadableByteChannel	A new readable byte channel

newChannel

Added in API level 1

public static WritableByteChannel newChannel (OutputStream out)

Constructs a channel that writes bytes to the given stream.

The resulting channel will not be buffered; it will simply redirect its I/O operations to the given stream. Closing the channel will in turn cause the stream to be closed.

Parameters
out	OutputStream: The stream to which bytes are to be written

Returns
WritableByteChannel	A new writable byte channel

newInputStream

Added in API level 1

public static InputStream newInputStream (ReadableByteChannel ch)

Constructs a stream that reads bytes from the given channel.

The read methods of the resulting stream will throw an IllegalBlockingModeException if invoked while the underlying channel is in non-blocking mode. The stream will not be buffered, and it will not support the mark or reset methods. The stream will be safe for access by multiple concurrent threads. Closing the stream will in turn cause the channel to be closed.

Parameters
ch	ReadableByteChannel: The channel from which bytes will be read

Returns
InputStream	A new input stream

newInputStream

Added in API level 26

public static InputStream newInputStream (AsynchronousByteChannel ch)

Constructs a stream that reads bytes from the given channel.

The stream will not be buffered, and it will not support the mark or reset methods. The stream will be safe for access by multiple concurrent threads. Closing the stream will in turn cause the channel to be closed.

Parameters
ch	AsynchronousByteChannel: The channel from which bytes will be read

Returns
InputStream	A new input stream

newOutputStream

Added in API level 26

public static OutputStream newOutputStream (AsynchronousByteChannel ch)

Constructs a stream that writes bytes to the given channel.

The stream will not be buffered. The stream will be safe for access by multiple concurrent threads. Closing the stream will in turn cause the channel to be closed.

Parameters
ch	AsynchronousByteChannel: The channel to which bytes will be written

Returns
OutputStream	A new output stream

newOutputStream

Added in API level 1

public static OutputStream newOutputStream (WritableByteChannel ch)

Constructs a stream that writes bytes to the given channel.

The write methods of the resulting stream will throw an IllegalBlockingModeException if invoked while the underlying channel is in non-blocking mode. The stream will not be buffered. The stream will be safe for access by multiple concurrent threads. Closing the stream will in turn cause the channel to be closed.

Parameters
ch	WritableByteChannel: The channel to which bytes will be written

Returns
OutputStream	A new output stream

newReader

Added in API level 33

public static Reader newReader (ReadableByteChannel ch, 
                Charset charset)

Constructs a reader that decodes bytes from the given channel according to the given charset.

An invocation of this method of the form

 Channels.newReader(ch, charset)
  

behaves in exactly the same way as the expression

 Channels.newReader(ch, Charset.forName(csName).newDecoder(), -1)
  

The reader's default action for malformed-input and unmappable-character errors is to report them. When more control over the error handling is required, the constructor that takes a CharsetDecoder should be used.

Parameters
ch	ReadableByteChannel: The channel from which bytes will be read
charset	Charset: The charset to be used

Returns
Reader	A new reader

newReader

Added in API level 1

public static Reader newReader (ReadableByteChannel ch, 
                CharsetDecoder dec, 
                int minBufferCap)

Constructs a reader that decodes bytes from the given channel using the given decoder.

The resulting stream will contain an internal input buffer of at least minBufferCap bytes. The stream's read methods will, as needed, fill the buffer by reading bytes from the underlying channel; if the channel is in non-blocking mode when bytes are to be read then an IllegalBlockingModeException will be thrown. The resulting stream will not otherwise be buffered, and it will not support the mark or reset methods. Closing the stream will in turn cause the channel to be closed.

Parameters
ch	ReadableByteChannel: The channel from which bytes will be read
dec	CharsetDecoder: The charset decoder to be used
minBufferCap	int: The minimum capacity of the internal byte buffer, or -1 if an implementation-dependent default capacity is to be used

Returns
Reader	A new reader

newReader

Added in API level 1

public static Reader newReader (ReadableByteChannel ch, 
                String csName)

Constructs a reader that decodes bytes from the given channel according to the named charset.

An invocation of this method of the form

 Channels.newReader(ch, csname)
  

behaves in exactly the same way as the expression

 Channels.newReader(ch, Charset.forName(csName))
  

Parameters
ch	ReadableByteChannel: The channel from which bytes will be read
csName	String: The name of the charset to be used

Returns
Reader	A new reader

Throws
UnsupportedCharsetException	If no support for the named charset is available in this instance of the Java virtual machine

newWriter

Added in API level 1

public static Writer newWriter (WritableByteChannel ch, 
                CharsetEncoder enc, 
                int minBufferCap)

Constructs a writer that encodes characters using the given encoder and writes the resulting bytes to the given channel.

The resulting stream will contain an internal output buffer of at least minBufferCap bytes. The stream's write methods will, as needed, flush the buffer by writing bytes to the underlying channel; if the channel is in non-blocking mode when bytes are to be written then an IllegalBlockingModeException will be thrown. The resulting stream will not otherwise be buffered. Closing the stream will in turn cause the channel to be closed.

Parameters
ch	WritableByteChannel: The channel to which bytes will be written
enc	CharsetEncoder: The charset encoder to be used
minBufferCap	int: The minimum capacity of the internal byte buffer, or -1 if an implementation-dependent default capacity is to be used

Returns
Writer	A new writer

newWriter

Added in API level 33

public static Writer newWriter (WritableByteChannel ch, 
                Charset charset)

Constructs a writer that encodes characters according to the given charset and writes the resulting bytes to the given channel.

An invocation of this method of the form

 Channels.newWriter(ch, charset)
  

behaves in exactly the same way as the expression

 Channels.newWriter(ch, Charset.forName(csName).newEncoder(), -1)
  

The writer's default action for malformed-input and unmappable-character errors is to report them. When more control over the error handling is required, the constructor that takes a CharsetEncoder should be used.

Parameters
ch	WritableByteChannel: The channel to which bytes will be written
charset	Charset: The charset to be used

Returns
Writer	A new writer

newWriter

Added in API level 1

public static Writer newWriter (WritableByteChannel ch, 
                String csName)

Constructs a writer that encodes characters according to the named charset and writes the resulting bytes to the given channel.

An invocation of this method of the form

 Channels.newWriter(ch, csname)
  

behaves in exactly the same way as the expression

 Channels.newWriter(ch, Charset.forName(csName))
  

Parameters
ch	WritableByteChannel: The channel to which bytes will be written
csName	String: The name of the charset to be used

Returns
Writer	A new writer

Throws
UnsupportedCharsetException	If no support for the named charset is available in this instance of the Java virtual machine