| java.lang.Object | ||||
| ↳ | java.nio.channels.spi.AbstractInterruptibleChannel | |||
| ↳ | java.nio.channels.SelectableChannel | |||
| ↳ | java.nio.channels.spi.AbstractSelectableChannel | |||
| ↳ | java.nio.channels.SocketChannel | |||
A SocketChannel is a selectable channel that provides a partial
abstraction of stream connecting socket. socket() returns the related
Socket instance which can handle the socket.
A socket channel is open but not connected when created by open().
After connecting it by calling connect(SocketAddress), it will remain
connected until it gets closed. If the connection is non-blocking then
connect(SocketAddress) is used to initiate the connection, followed
by a call of finishConnect() to perform the final steps of
connecting. isConnectionPending() indicates if the connection is
blocked or not; isConnected() indicates if the socket is finally
connected or not.
The input and output sides of a channel can be shut down independently and
asynchronously without closing the channel. The shutdownInput method
is used for the input side of a channel and subsequent read operations return
-1, which means end of stream. If another thread is blocked in a read
operation when the shutdown occurs, the read will end without effect and
return end of stream. The shutdownOutput method is used for the
output side of the channel; subsequent write operations throw a
ClosedChannelException. If the output is shut down and another thread
is blocked in a write operation, an AsynchronousCloseException will
be thrown to the pending thread.
Socket channels are thread-safe, no more than one thread can read or write at
any given time. The connect(SocketAddress) and finishConnect() methods are synchronized against each other; when they are
processing, calls to read and write will block.
| Protected Constructors | |||||||||||
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Constructs a new
SocketChannel. | |||||||||||
| Public Methods | |||||||||||
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Connects this channel's socket with a remote address.
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Completes the connection process initiated by a call of
connect(SocketAddress). | |||||||||||
Indicates whether this channel's socket is connected.
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Indicates whether this channel's socket is still trying to connect.
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Creates an open and unconnected socket channel.
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Creates a socket channel and connects it to a socket address.
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Reads bytes from this socket channel into the given buffer.
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Reads bytes from this socket channel into a subset of the given buffers.
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Reads bytes from this socket channel and stores them in the specified
array of buffers.
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Returns the socket assigned to this channel, which does not declare any public
methods that are not declared in
Socket. | |||||||||||
Gets the valid operations of this channel.
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Writes bytes from all the given byte buffers to this socket channel.
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Attempts to write a subset of the given bytes from the buffers to this
socket channel.
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Writes bytes from the given byte buffer to this socket channel.
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[Expand]
Inherited Methods | |||||||||||
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From class
java.nio.channels.spi.AbstractSelectableChannel
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From class
java.nio.channels.SelectableChannel
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From class
java.nio.channels.spi.AbstractInterruptibleChannel
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From class
java.lang.Object
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From interface
java.io.Closeable
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From interface
java.nio.channels.Channel
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From interface
java.nio.channels.GatheringByteChannel
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From interface
java.nio.channels.InterruptibleChannel
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From interface
java.nio.channels.ReadableByteChannel
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From interface
java.nio.channels.ScatteringByteChannel
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From interface
java.nio.channels.WritableByteChannel
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Constructs a new SocketChannel.
| selectorProvider | an instance of SelectorProvider. |
|---|
Connects this channel's socket with a remote address.
If this channel is blocking, this method will suspend until connecting is
finished or an I/O exception occurs. If the channel is non-blocking,
this method will return true if the connection is finished at
once or return false when the connection must be finished later
by calling finishConnect().
This method can be called at any moment and can block other read and
write operations while connecting. It executes the same security checks
as the connect method of the Socket class.
| address | the address to connect with. |
|---|
true if the connection is finished, false
otherwise.| AlreadyConnectedException | if the channel is already connected. |
|---|---|
| ConnectionPendingException | a non-blocking connecting operation is already executing on this channel. |
| ClosedChannelException | if this channel is closed. |
| AsynchronousCloseException | if this channel is closed by another thread while this method is executing. |
| ClosedByInterruptException | if another thread interrupts the calling thread while this operation is in progress. The calling thread will have the interrupt state set and this channel will be closed. |
| UnresolvedAddressException | if the address is not resolved. |
| UnsupportedAddressTypeException | if the address type is not supported. |
| IOException | if an I/O error occurs. |
Completes the connection process initiated by a call of connect(SocketAddress).
This method returns true if the connection is finished already
and returns false if the channel is non-blocking and the
connection is not finished yet.
If this channel is in blocking mode, this method will suspend and return
true when the connection is finished. It closes this channel and
throws an exception if the connection fails.
This method can be called at any moment and it can block other read and write operations while connecting.
true if the connection is successfully finished, false otherwise.| NoConnectionPendingException | if the channel is not connected and the connection process has not been initiated. |
|---|---|
| ClosedChannelException | if this channel is closed. |
| AsynchronousCloseException | if this channel is closed by another thread while this method is executing. |
| ClosedByInterruptException | if another thread interrupts the calling thread while this operation is in progress. The calling thread has the interrupt state set, and this channel is closed. |
| IOException | if an I/O error occurs. |
Indicates whether this channel's socket is connected.
true if this channel's socket is connected, false
otherwise.
Indicates whether this channel's socket is still trying to connect.
true if the connection is initiated but not finished;
false otherwise.
Creates an open and unconnected socket channel.
This channel is created by calling openSocketChannel() of the
default SelectorProvider instance.
| IOException | if an I/O error occurs. |
|---|
Creates a socket channel and connects it to a socket address.
This method performs a call to open() followed by a call to
connect(SocketAddress).
| address | the socket address to be connected to. |
|---|
| AsynchronousCloseException | if this channel is closed by another thread while this method is executing. |
|---|---|
| ClosedByInterruptException | if another thread interrupts the calling thread while this operation is executing. The calling thread will have the interrupt state set and the channel will be closed. |
| UnresolvedAddressException | if the address is not resolved. |
| UnsupportedAddressTypeException | if the address type is not supported. |
| IOException | if an I/O error occurs. |
Reads bytes from this socket channel into the given buffer.
The maximum number of bytes that will be read is the remaining number of bytes in the buffer when the method is invoked. The bytes will be copied into the buffer starting at the buffer's current position.
The call may block if other threads are also attempting to read from this channel.
Upon completion, the buffer's position is set to the end of the bytes that have been read. The buffer's limit is not changed.
| target | the byte buffer to receive the bytes. |
|---|
| AsynchronousCloseException | if another thread closes the channel during the read. |
|---|---|
| NotYetConnectedException | if this channel is not yet connected. |
| ClosedByInterruptException | if another thread interrupts the calling thread while this operation is in progress. The interrupt state of the calling thread is set and the channel is closed. |
| ClosedChannelException | if this channel is closed. |
| IOException | if another I/O error occurs. |
Reads bytes from this socket channel into a subset of the given buffers.
This method attempts to read all remaining() bytes from length byte buffers, in order, starting at targets[offset]. The
number of bytes actually read is returned.
If a read operation is in progress, subsequent threads will block until the read is completed and will then contend for the ability to read.
| targets | the array of byte buffers into which the bytes will be copied. |
|---|---|
| offset | the index of the first buffer to store bytes in. |
| length | the maximum number of buffers to store bytes in. |
| AsynchronousCloseException | if this channel is closed by another thread during this read operation. |
|---|---|
| ClosedByInterruptException | if another thread interrupts the calling thread while this operation is in progress. The interrupt state of the calling thread is set and the channel is closed. |
| ClosedChannelException | if this channel is closed. |
| IndexOutOfBoundsException | if offset < 0 or length < 0, or if offset + length is greater than the size of targets. |
| IOException | if another I/O error occurs. |
| NotYetConnectedException | if this channel is not yet connected. |
Reads bytes from this socket channel and stores them in the specified array of buffers. This method attempts to read as many bytes as can be stored in the buffer array from this channel and returns the number of bytes actually read.
If a read operation is in progress, subsequent threads will block until the read is completed and will then contend for the ability to read.
Calling this method is equivalent to calling read(targets, 0,
targets.length);
| targets | the array of byte buffers into which the bytes will be copied. |
|---|
| AsynchronousCloseException | if this channel is closed by another thread during this read operation. |
|---|---|
| ClosedByInterruptException | if another thread interrupts the calling thread while this operation is in progress. The interrupt state of the calling thread is set and the channel is closed. |
| ClosedChannelException | if this channel is closed. |
| IOException | if another I/O error occurs. |
| NotYetConnectedException | if this channel is not yet connected. |
Returns the socket assigned to this channel, which does not declare any public
methods that are not declared in Socket.
Gets the valid operations of this channel. Socket channels support
connect, read and write operation, so this method returns
SelectionKey.OP_CONNECT | SelectionKey.OP_READ | SelectionKey.OP_WRITE.
Writes bytes from all the given byte buffers to this socket channel.
Calling this method is equivalent to calling write(sources, 0,
sources.length);
| sources | the buffers containing bytes to write. |
|---|
| AsynchronousCloseException | if this channel is closed by another thread during this write operation. |
|---|---|
| ClosedByInterruptException | if another thread interrupts the calling thread while this operation is in progress. The interrupt state of the calling thread is set and the channel is closed. |
| ClosedChannelException | if this channel is closed. |
| IOException | if another I/O error occurs. |
| NotYetConnectedException | if this channel is not yet connected. |
Attempts to write a subset of the given bytes from the buffers to this
socket channel. This method attempts to write all remaining()
bytes from length byte buffers, in order, starting at sources[offset]. The number of bytes actually written is returned.
If a write operation is in progress, subsequent threads will block until the write is completed and then contend for the ability to write.
| sources | the array of byte buffers that is the source for bytes written to this channel. |
|---|---|
| offset | the index of the first buffer in buffers to get bytes
from. |
| length | the number of buffers to get bytes from. |
| AsynchronousCloseException | if this channel is closed by another thread during this write operation. |
|---|---|
| ClosedByInterruptException | if another thread interrupts the calling thread while this operation is in progress. The interrupt state of the calling thread is set and the channel is closed. |
| ClosedChannelException | if this channel is closed. |
| IndexOutOfBoundsException | if offset < 0 or length < 0, or if offset + length is greater than the size of sources. |
| IOException | if another I/O error occurs. |
| NotYetConnectedException | if this channel is not yet connected. |
Writes bytes from the given byte buffer to this socket channel. The maximum number of bytes that are written is the remaining number of bytes in the buffer when this method is invoked. The bytes are taken from the buffer starting at the buffer's position.
The call may block if other threads are also attempting to write to the same channel.
Upon completion, the buffer's position is updated to the end of the bytes that have been written. The buffer's limit is not changed.
| source | the byte buffer containing the bytes to be written. |
|---|
| AsynchronousCloseException | if another thread closes the channel during the write. |
|---|---|
| ClosedByInterruptException | if another thread interrupts the calling thread while this operation is in progress. The interrupt state of the calling thread is set and the channel is closed. |
| ClosedChannelException | if the channel was already closed. |
| IOException | if another I/O error occurs. |
| NotYetConnectedException | if this channel is not connected yet. |