Added in API level 1

Summary: Protected Ctors | Methods | Protected Methods | Inherited Methods

AbstractSelectableChannel

public abstract class AbstractSelectableChannel
extends SelectableChannel

java.lang.Object
↳	java.nio.channels.spi.AbstractInterruptibleChannel
	↳	java.nio.channels.SelectableChannel
		↳	java.nio.channels.spi.AbstractSelectableChannel

Known direct subclasses

DatagramChannel, Pipe.SinkChannel, Pipe.SourceChannel, ServerSocketChannel, SocketChannel

DatagramChannel	A selectable channel for datagram-oriented sockets.
Pipe.SinkChannel	A channel representing the writable end of a `Pipe`.
Pipe.SourceChannel	A channel representing the readable end of a `Pipe`.
ServerSocketChannel	A selectable channel for stream-oriented listening sockets.
SocketChannel	A selectable channel for stream-oriented connecting sockets.

Base implementation class for selectable channels.

This class defines methods that handle the mechanics of channel registration, deregistration, and closing. It maintains the current blocking mode of this channel as well as its current set of selection keys. It performs all of the synchronization required to implement the SelectableChannel specification. Implementations of the abstract protected methods defined in this class need not synchronize against other threads that might be engaged in the same operations.

Summary

Protected constructors
`AbstractSelectableChannel(SelectorProvider provider)` Initializes a new instance of this class.

Public methods
`final Object`	`blockingLock()` Retrieves the object upon which the `configureBlocking` and `register` methods synchronize.
`final SelectableChannel`	`configureBlocking(boolean block)` Adjusts this channel's blocking mode.
`final boolean`	`isBlocking()` Tells whether or not every I/O operation on this channel will block until it completes.
`final boolean`	`isRegistered()` Tells whether or not this channel is currently registered with any selectors.
`final SelectionKey`	`keyFor(Selector sel)` Retrieves the key representing the channel's registration with the given selector.
`final SelectorProvider`	`provider()` Returns the provider that created this channel.
`final SelectionKey`	`register(Selector sel, int ops, Object att)` Registers this channel with the given selector, returning a selection key.

Protected methods
`final void`	`implCloseChannel()` Closes this channel.
`abstract void`	`implCloseSelectableChannel()` Closes this selectable channel.
`abstract void`	`implConfigureBlocking(boolean block)` Adjusts this channel's blocking mode.

Inherited methods

From class


        
          java.nio.channels.SelectableChannel

`abstract Object`	`blockingLock()` Retrieves the object upon which the `configureBlocking` and `register` methods synchronize.
`abstract SelectableChannel`	`configureBlocking(boolean block)` Adjusts this channel's blocking mode.
`abstract boolean`	`isBlocking()` Tells whether or not every I/O operation on this channel will block until it completes.
`abstract boolean`	`isRegistered()` Tells whether or not this channel is currently registered with any selectors.
`abstract SelectionKey`	`keyFor(Selector sel)` Retrieves the key representing the channel's registration with the given selector.
`abstract SelectorProvider`	`provider()` Returns the provider that created this channel.
`abstract SelectionKey`	`register(Selector sel, int ops, Object att)` Registers this channel with the given selector, returning a selection key.
`final SelectionKey`	`register(Selector sel, int ops)` Registers this channel with the given selector, returning a selection key.
`abstract int`	`validOps()` Returns an operation set identifying this channel's supported operations.

From class


        
          java.nio.channels.spi.AbstractInterruptibleChannel

`final void`	`begin()` Marks the beginning of an I/O operation that might block indefinitely.
`final void`	`close()` Closes this channel.
`final void`	`end(boolean completed)` Marks the end of an I/O operation that might block indefinitely.
`abstract void`	`implCloseChannel()` Closes this channel.
`final boolean`	`isOpen()` Tells whether or not this channel is open.

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.

From interface


        
          java.nio.channels.Channel

`abstract void`	`close()` Closes this channel.
`abstract boolean`	`isOpen()` Tells whether or not this channel is open.

From interface


        
          java.nio.channels.InterruptibleChannel


      close()

Closes this channel.

From interface


        
          java.io.Closeable


      close()

Closes this stream and releases any system resources associated with it.

From interface


        
          java.lang.AutoCloseable


      close()

Closes this resource, relinquishing any underlying resources.

Protected constructors

AbstractSelectableChannel

Added in API level 1

protected AbstractSelectableChannel (SelectorProvider provider)

Initializes a new instance of this class.

Parameters
`provider`	`SelectorProvider`: The provider that created this channel

Public methods

blockingLock

Added in API level 1

public final Object blockingLock ()

Retrieves the object upon which the configureBlocking and register methods synchronize. This is often useful in the implementation of adaptors that require a specific blocking mode to be maintained for a short period of time.

Returns
`Object`	The blocking-mode lock object

configureBlocking

Added in API level 1

public final SelectableChannel configureBlocking (boolean block)

Adjusts this channel's blocking mode.

If the given blocking mode is different from the current blocking mode then this method invokes the implConfigureBlocking method, while holding the appropriate locks, in order to change the mode.

Parameters
`block`	`boolean`: If `true` then this channel will be placed in blocking mode; if `false` then it will be placed non-blocking mode

Returns
`SelectableChannel`	This selectable channel

Throws
`IOException`

isBlocking

Added in API level 1

public final boolean isBlocking ()

Tells whether or not every I/O operation on this channel will block until it completes. A newly-created channel is always in blocking mode.

If this channel is closed then the value returned by this method is not specified.

Returns
`boolean`	`true` if, and only if, this channel is in blocking mode

isRegistered

Added in API level 1

public final boolean isRegistered ()

Tells whether or not this channel is currently registered with any selectors. A newly-created channel is not registered.

Due to the inherent delay between key cancellation and channel deregistration, a channel may remain registered for some time after all of its keys have been cancelled. A channel may also remain registered for some time after it is closed.

Returns
`boolean`	`true` if, and only if, this channel is registered

keyFor

Added in API level 1

public final SelectionKey keyFor (Selector sel)

Retrieves the key representing the channel's registration with the given selector.

Parameters
`sel`	`Selector`: The selector

Returns
`SelectionKey`	The key returned when this channel was last registered with the given selector, or `null` if this channel is not currently registered with that selector

provider

Added in API level 1

public final SelectorProvider provider ()

Returns the provider that created this channel.

Returns
`SelectorProvider`	The provider that created this channel

register

Added in API level 1

public final SelectionKey register (Selector sel, 
                int ops, 
                Object att)

Registers this channel with the given selector, returning a selection key.

This method first verifies that this channel is open and that the given initial interest set is valid.

If this channel is already registered with the given selector then the selection key representing that registration is returned after setting its interest set to the given value.

Otherwise this channel has not yet been registered with the given selector, so the register method of the selector is invoked while holding the appropriate locks. The resulting key is added to this channel's key set before being returned.

Parameters
`sel`	`Selector`: The selector with which this channel is to be registered
`ops`	`int`: The interest set for the resulting key
`att`	`Object`: The attachment for the resulting key; may be `null`

Returns
`SelectionKey`	A key representing the registration of this channel with the given selector

Throws
`ClosedSelectorException`
`IllegalBlockingModeException`
`IllegalSelectorException`
`CancelledKeyException`
`IllegalArgumentException`
`ClosedChannelException`

Protected methods

implCloseChannel

Added in API level 1

protected final void implCloseChannel ()

Closes this channel.

This method, which is specified in the AbstractInterruptibleChannel class and is invoked by the close method, in turn invokes the implCloseSelectableChannel method in order to perform the actual work of closing this channel. It then cancels all of this channel's keys.

Throws
`IOException`

implCloseSelectableChannel

Added in API level 1

protected abstract void implCloseSelectableChannel ()

Closes this selectable channel.

This method is invoked by the close method in order to perform the actual work of closing the channel. This method is only invoked if the channel has not yet been closed, and it is never invoked more than once.

An implementation of this method must arrange for any other thread that is blocked in an I/O operation upon this channel to return immediately, either by throwing an exception or by returning normally.

Throws
`IOException`	If an I/O error occurs

implConfigureBlocking

Added in API level 1

protected abstract void implConfigureBlocking (boolean block)

Adjusts this channel's blocking mode.

This method is invoked by the configureBlocking method in order to perform the actual work of changing the blocking mode. This method is only invoked if the new mode is different from the current mode.

Parameters
`block`	`boolean`: If `true` then this channel will be placed in blocking mode; if `false` then it will be placed non-blocking mode

Throws
`IOException`	If an I/O error occurs