public abstract Class SocketChannel

Redeclares java.nio.channels.NetworkChannel.bind.

Binds the channel's socket to a local address.

This method is used to establish an association between the socket and a local address. For Internet Protocol sockets, once an association is established then the socket remains bound until the channel is closed. If the local parameter has the value null then the socket will be bound to an address that is assigned automatically.

Parameters

local:SocketAddress

The address to bind the socket, or null to bind the socket to an automatically assigned socket address

Returns:SocketChannel

This channel

Annotations

@Override

Exceptions

IOException:

If some other I/O error occurs

ConnectionPendingException:

If a non-blocking connect operation is already in progress on this channel

AlreadyBoundException:

If the socket is already bound

UnsupportedAddressTypeException:

If the type of the given address is not supported

ClosedChannelException:

If the channel is closed

SecurityException:

If a security manager has been installed and its checkListen method denies the operation for an Internet protocol socket address, or for a Unix domain socket address if it denies NetPermission("accessUnixDomainSocket").

Since

1.7

Connects this channel's socket.

If this channel is in non-blocking mode then an invocation of this method initiates a non-blocking connection operation. If the connection is established immediately, as can happen with a local connection, then this method returns true. Otherwise this method returns false and the connection operation must later be completed by invoking the finishConnect method.

If this channel is in blocking mode then an invocation of this method will block until the connection is established or an I/O error occurs.

For channels to Internet protocol sockets, this method performs exactly the same security checks as the java.net.Socket class. That is, if a security manager has been installed then this method verifies that its checkConnect method permits connecting to the address and port number of the given remote endpoint.

For channels to Unix Domain sockets, this method checks NetPermission("accessUnixDomainSocket") with the security manager's checkPermission method.

This method may be invoked at any time. If a read or write operation upon this channel is invoked while an invocation of this method is in progress then that operation will first block until this invocation is complete. If a connection attempt is initiated but fails, that is, if an invocation of this method throws a checked exception, then the channel will be closed.

Parameters

remote:SocketAddress

The remote address to which this channel is to be connected

Returns:boolean

true if a connection was established, false if this channel is in non-blocking mode and the connection operation is in progress

Exceptions

IOException:

If some other I/O error occurs

AlreadyConnectedException:

If this channel is already connected

ConnectionPendingException:

If a non-blocking connection operation is already in progress on this channel

ClosedChannelException:

If this channel is closed

AsynchronousCloseException:

If another thread closes this channel while the connect operation is in progress

ClosedByInterruptException:

If another thread interrupts the current thread while the connect operation is in progress, thereby closing the channel and setting the current thread's interrupt status

UnresolvedAddressException:

If the given remote address is an InetSocketAddress that is not fully resolved

UnsupportedAddressTypeException:

If the type of the given remote address is not supported

SecurityException:

If a security manager has been installed and it does not permit access to the given remote endpoint

Finishes the process of connecting a socket channel.

A non-blocking connection operation is initiated by placing a socket channel in non-blocking mode and then invoking its connect method. Once the connection is established, or the attempt has failed, the socket channel will become connectable and this method may be invoked to complete the connection sequence. If the connection operation failed then invoking this method will cause an appropriate java.io.IOException to be thrown.

If this channel is already connected then this method will not block and will immediately return true. If this channel is in non-blocking mode then this method will return false if the connection process is not yet complete. If this channel is in blocking mode then this method will block until the connection either completes or fails, and will always either return true or throw a checked exception describing the failure.

This method may be invoked at any time. If a read or write operation upon this channel is invoked while an invocation of this method is in progress then that operation will first block until this invocation is complete. If a connection attempt fails, that is, if an invocation of this method throws a checked exception, then the channel will be closed.

Returns:boolean

true if, and only if, this channel's socket is now connected

Exceptions

IOException:

If some other I/O error occurs

NoConnectionPendingException:

If this channel is not connected and a connection operation has not been initiated

ClosedChannelException:

If this channel is closed

AsynchronousCloseException:

If another thread closes this channel while the connect operation is in progress

ClosedByInterruptException:

If another thread interrupts the current thread while the connect operation is in progress, thereby closing the channel and setting the current thread's interrupt status

Redeclares java.nio.channels.NetworkChannel.getLocalAddress.

Doc from java.nio.channels.NetworkChannel.getLocalAddress.

Returns the socket address that this channel's socket is bound to.

Where the channel is bound to an Internet Protocol socket address then the return value from this method is of type java.net.InetSocketAddress. If there is a security manager set, its checkConnect method is called with the local address and -1 as its arguments to see if the operation is allowed. If the operation is not allowed, a SocketAddress representing the loopback address and the local port of the channel's socket is returned.

Where the channel is bound to a Unix Domain socket address, the socket address is a UnixDomainSocketAddress. If there is a security manager set, its checkPermission method is called with NetPermission("accessUnixDomainSocket"). If the operation is not allowed an unnamed UnixDomainSocketAddress is returned.

Returns:SocketAddress

The SocketAddress that the socket is bound to, or the SocketAddress representing the loopback address or empty path if denied by the security manager, or null if the channel's socket is not bound

Annotations

@Override

Exceptions

IOException:

If an I/O error occurs

ClosedChannelException:

If the channel is closed

Returns the remote address to which this channel's socket is connected.

Where the channel's socket is bound and connected to an Internet Protocol socket address then the return value is of type java.net.InetSocketAddress.

Where the channel's socket is bound and connected to a Unix Domain socket address, the returned address is a UnixDomainSocketAddress.

Returns:SocketAddress

The remote address; null if the channel's socket is not connected

Exceptions

IOException:

If an I/O error occurs

ClosedChannelException:

If the channel is closed

Since

1.7

Tells whether or not this channel's network socket is connected.

Returns:boolean

true if, and only if, this channel's network socket is open and connected

Tells whether or not a connection operation is in progress on this channel.

Returns:boolean

true if, and only if, a connection operation has been initiated on this channel but not yet completed by invoking the finishConnect method

Opens a socket channel for an Internet protocol socket.

The new channel is created by invoking the openSocketChannel method of the system-wide default java.nio.channels.spi.SelectorProvider object.

Returns:SocketChannel

A new socket channel

Exceptions

IOException:

If an I/O error occurs

See Also

java.net.preferIPv4Stack system property

Opens a socket channel. The family parameter specifies the protocol family of the channel's socket.

The new channel is created by invoking the openSocketChannel(ProtocolFamily) method of the system-wide default. java.nio.channels.spi.SelectorProvider object.

Parameters

family:ProtocolFamily

The protocol family

Returns:SocketChannel

A new socket channel

Exceptions

IOException:

If an I/O error occurs

UnsupportedOperationException:

If the specified protocol family is not supported. For example, suppose the parameter is specified as StandardProtocolFamily.INET6 but IPv6 is not enabled on the platform.

Since

15

See Also

java.net.preferIPv4Stack system property

Opens a socket channel and connects it to a remote address.

If the remote address is an InetSocketAddress then this method works as if by invoking the open() method, invoking the connect method upon the resulting socket channel, passing it remote, and then returning that channel.

If the remote address is a UnixDomainSocketAddress then this works by invoking the open(ProtocolFamily) method with StandardProtocolFamily#UNIX as parameter, invoking the connect method upon the resulting socket channel, passing it remote, then returning that channel.

Parameters

remote:SocketAddress

The remote address to which the new channel is to be connected

Returns:SocketChannel

A new, and connected, socket channel

Exceptions

IOException:

If some other I/O error occurs

AsynchronousCloseException:

If another thread closes this channel while the connect operation is in progress

ClosedByInterruptException:

If another thread interrupts the current thread while the connect operation is in progress, thereby closing the channel and setting the current thread's interrupt status

UnresolvedAddressException:

If the given remote address is an InetSocketAddress that is not fully resolved

UnsupportedAddressTypeException:

If the type of the given remote address is not supported

SecurityException:

If a security manager has been installed and it does not permit access to the given remote endpoint

See Also

java.net.preferIPv4Stack system property

Redeclares java.nio.channels.ReadableByteChannel.read.

Doc from java.nio.channels.ReadableByteChannel.read.

Reads a sequence of bytes from this channel into the given buffer.

An attempt is made to read up to r bytes from the channel, where r is the number of bytes remaining in the buffer, that is, dst.remaining(), at the moment this method is invoked.

Suppose that a byte sequence of length n is read, where 0 <= n <= r. This byte sequence will be transferred into the buffer so that the first byte in the sequence is at index p and the last byte is at index p + n - 1, where p is the buffer's position at the moment this method is invoked. Upon return the buffer's position will be equal to p + n; its limit will not have changed.

A read operation might not fill the buffer, and in fact it might not read any bytes at all. Whether or not it does so depends upon the nature and state of the channel. A socket channel in non-blocking mode, for example, cannot read any more bytes than are immediately available from the socket's input buffer; similarly, a file channel cannot read any more bytes than remain in the file. It is guaranteed, however, that if a channel is in blocking mode and there is at least one byte remaining in the buffer then this method will block until at least one byte is read.

This method may be invoked at any time. If another thread has already initiated a read operation upon this channel, however, then an invocation of this method will block until the first operation is complete.

Parameters

dst:ByteBuffer

The buffer into which bytes are to be transferred

Returns:int

The number of bytes read, possibly zero, or -1 if the channel has reached end-of-stream

Exceptions

IOException:

If some other I/O error occurs

NotYetConnectedException:

If this channel is not yet connected

ClosedChannelException:

If this channel is closed

AsynchronousCloseException:

If another thread closes this channel while the read operation is in progress

ClosedByInterruptException:

If another thread interrupts the current thread while the read operation is in progress, thereby closing the channel and setting the current thread's interrupt status

Redeclares java.nio.channels.ScatteringByteChannel.read.

Doc from java.nio.channels.ScatteringByteChannel.read.

Reads a sequence of bytes from this channel into a subsequence of the given buffers.

An invocation of this method attempts to read up to r bytes from this channel, where r is the total number of bytes remaining in the specified subsequence of the given buffer array, that is,

dsts[offset].remaining()
    + dsts[offset+1].remaining()
    + ... + dsts[offset+length-1].remaining()

Suppose that a byte sequence of length n is read, where 0 <= n <= r. Up to the first dsts[offset].remaining() bytes of this sequence are transferred into buffer dsts[offset], up to the next dsts[offset+1].remaining() bytes are transferred into buffer dsts[offset+1], and so forth, until the entire byte sequence is transferred into the given buffers. As many bytes as possible are transferred into each buffer, hence the final position of each updated buffer, except the last updated buffer, is guaranteed to be equal to that buffer's limit.

This method may be invoked at any time. If another thread has already initiated a read operation upon this channel, however, then an invocation of this method will block until the first operation is complete.

Parameters

dsts:ByteBuffer[]

The buffers into which bytes are to be transferred

offset:int

The offset within the buffer array of the first buffer into which bytes are to be transferred; must be non-negative and no larger than dsts.length

length:int

The maximum number of buffers to be accessed; must be non-negative and no larger than dsts.length - offset

Returns:long

The number of bytes read, possibly zero, or -1 if the channel has reached end-of-stream

Exceptions

IOException:

If some other I/O error occurs

NotYetConnectedException:

If this channel is not yet connected

ClosedChannelException:

If this channel is closed

AsynchronousCloseException:

If another thread closes this channel while the read operation is in progress

ClosedByInterruptException:

If another thread interrupts the current thread while the read operation is in progress, thereby closing the channel and setting the current thread's interrupt status

Implements java.nio.channels.ScatteringByteChannel.read.

Doc from java.nio.channels.ScatteringByteChannel.read.

Reads a sequence of bytes from this channel into the given buffers.

An invocation of this method of the form c.read(dsts) behaves in exactly the same manner as the invocation

c.read(dsts, 0, dsts.length);

Parameters

dsts:ByteBuffer[]

The buffers into which bytes are to be transferred

Returns:long

The number of bytes read, possibly zero, or -1 if the channel has reached end-of-stream

Exceptions

IOException:

If some other I/O error occurs

NotYetConnectedException:

If this channel is not yet connected

ClosedChannelException:

If this channel is closed

AsynchronousCloseException:

If another thread closes this channel while the read operation is in progress

ClosedByInterruptException:

If another thread interrupts the current thread while the read operation is in progress, thereby closing the channel and setting the current thread's interrupt status

Redeclares java.nio.channels.NetworkChannel.setOption.

Doc from java.nio.channels.NetworkChannel.setOption.

Sets the value of a socket option.

Parameters

<T>

The type of the socket option value

name:SocketOption<T>

The socket option

value:T

The value of the socket option. A value of null may be a valid value for some socket options.

Returns:SocketChannel

This channel

Annotations

@Override

Exceptions

IOException:

If an I/O error occurs

UnsupportedOperationException:

If the socket option is not supported by this channel

IllegalArgumentException:

If the value is not a valid value for this socket option

ClosedChannelException:

If this channel is closed

Since

1.7

Shutdown the connection for reading without closing the channel.

Once shutdown for reading then further reads on the channel will return -1, the end-of-stream indication. If the input side of the connection is already shutdown then invoking this method has no effect.

Returns:SocketChannel

The channel

Exceptions

IOException:

If some other I/O error occurs

NotYetConnectedException:

If this channel is not yet connected

ClosedChannelException:

If this channel is closed

Since

1.7

Shutdown the connection for writing without closing the channel.

Once shutdown for writing then further attempts to write to the channel will throw ClosedChannelException. If the output side of the connection is already shutdown then invoking this method has no effect.

Returns:SocketChannel

The channel

Exceptions

IOException:

If some other I/O error occurs

NotYetConnectedException:

If this channel is not yet connected

ClosedChannelException:

If this channel is closed

Since

1.7

Retrieves a socket associated with this channel.

Returns:Socket

A socket associated with this channel

Exceptions

UnsupportedOperationException:

If the channel's socket is not an Internet protocol socket

Implements abstract java.nio.channels.SelectableChannel.validOps.

Returns an operation set identifying this channel's supported operations.

Socket channels support connecting, reading, and writing, so this method returns (SelectionKey#OP_CONNECT | SelectionKey#OP_READ | SelectionKey#OP_WRITE).

Returns:int

The valid-operation set

Redeclares java.nio.channels.WritableByteChannel.write.

Doc from java.nio.channels.WritableByteChannel.write.

Writes a sequence of bytes to this channel from the given buffer.

An attempt is made to write up to r bytes to the channel, where r is the number of bytes remaining in the buffer, that is, src.remaining(), at the moment this method is invoked.

Suppose that a byte sequence of length n is written, where 0 <= n <= r. This byte sequence will be transferred from the buffer starting at index p, where p is the buffer's position at the moment this method is invoked; the index of the last byte written will be p + n - 1. Upon return the buffer's position will be equal to p + n; its limit will not have changed.

Unless otherwise specified, a write operation will return only after writing all of the r requested bytes. Some types of channels, depending upon their state, may write only some of the bytes or possibly none at all. A socket channel in non-blocking mode, for example, cannot write any more bytes than are free in the socket's output buffer.

This method may be invoked at any time. If another thread has already initiated a write operation upon this channel, however, then an invocation of this method will block until the first operation is complete.

Parameters

src:ByteBuffer

The buffer from which bytes are to be retrieved

Returns:int

The number of bytes written, possibly zero

Exceptions

IOException:

If some other I/O error occurs

NotYetConnectedException:

If this channel is not yet connected

ClosedChannelException:

If this channel is closed

AsynchronousCloseException:

If another thread closes this channel while the write operation is in progress

ClosedByInterruptException:

If another thread interrupts the current thread while the write operation is in progress, thereby closing the channel and setting the current thread's interrupt status

Redeclares java.nio.channels.GatheringByteChannel.write.

Doc from java.nio.channels.GatheringByteChannel.write.

Writes a sequence of bytes to this channel from a subsequence of the given buffers.

An attempt is made to write up to r bytes to this channel, where r is the total number of bytes remaining in the specified subsequence of the given buffer array, that is,

srcs[offset].remaining()
    + srcs[offset+1].remaining()
    + ... + srcs[offset+length-1].remaining()

Suppose that a byte sequence of length n is written, where 0 <= n <= r. Up to the first srcs[offset].remaining() bytes of this sequence are written from buffer srcs[offset], up to the next srcs[offset+1].remaining() bytes are written from buffer srcs[offset+1], and so forth, until the entire byte sequence is written. As many bytes as possible are written from each buffer, hence the final position of each updated buffer, except the last updated buffer, is guaranteed to be equal to that buffer's limit.

Unless otherwise specified, a write operation will return only after writing all of the r requested bytes. Some types of channels, depending upon their state, may write only some of the bytes or possibly none at all. A socket channel in non-blocking mode, for example, cannot write any more bytes than are free in the socket's output buffer.

This method may be invoked at any time. If another thread has already initiated a write operation upon this channel, however, then an invocation of this method will block until the first operation is complete.

Parameters

srcs:ByteBuffer[]

The buffers from which bytes are to be retrieved

offset:int

The offset within the buffer array of the first buffer from which bytes are to be retrieved; must be non-negative and no larger than srcs.length

length:int

The maximum number of buffers to be accessed; must be non-negative and no larger than srcs.length - offset

Returns:long

The number of bytes written, possibly zero

Exceptions

IOException:

If some other I/O error occurs

NotYetConnectedException:

If this channel is not yet connected

ClosedChannelException:

If this channel is closed

AsynchronousCloseException:

If another thread closes this channel while the write operation is in progress

ClosedByInterruptException:

If another thread interrupts the current thread while the write operation is in progress, thereby closing the channel and setting the current thread's interrupt status

Implements java.nio.channels.GatheringByteChannel.write.

Doc from java.nio.channels.GatheringByteChannel.write.

Writes a sequence of bytes to this channel from the given buffers.

An invocation of this method of the form c.write(srcs) behaves in exactly the same manner as the invocation

c.write(srcs, 0, srcs.length);

Parameters

srcs:ByteBuffer[]

The buffers from which bytes are to be retrieved

Returns:long

The number of bytes written, possibly zero

Exceptions

IOException:

If some other I/O error occurs

NotYetConnectedException:

If this channel is not yet connected

ClosedChannelException:

If this channel is closed

AsynchronousCloseException:

If another thread closes this channel while the write operation is in progress

ClosedByInterruptException:

If another thread interrupts the current thread while the write operation is in progress, thereby closing the channel and setting the current thread's interrupt status