| java.lang.Object | |||
| ↳ | java.nio.channels.spi.AbstractInterruptibleChannel | ||
| ↳ | java.nio.channels.SelectableChannel | ||
| ↳ | java.nio.channels.spi.AbstractSelectableChannel | ||
 Known Direct Subclasses
|
Class Overview
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 | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
Initializes a new instance of this class.
| |||||||||||
| Public Methods | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
Retrieves the object upon which the
configureBlocking and register methods synchronize. | |||||||||||
Adjusts this channel's blocking mode.
| |||||||||||
Tells whether or not every I/O operation on this channel will block
until it completes.
| |||||||||||
Tells whether or not this channel is currently registered with any
selectors.
| |||||||||||
Retrieves the key representing the channel's registration with the given
selector.
| |||||||||||
Returns the provider that created this channel.
| |||||||||||
Registers this channel with the given selector, returning a selection key.
| |||||||||||
| Protected Methods | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
Closes this channel.
| |||||||||||
Closes this selectable channel.
| |||||||||||
Adjusts this channel's blocking mode.
| |||||||||||
|
[Expand]
Inherited Methods | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
|
From class
java.nio.channels.SelectableChannel
| |||||||||||
|
From class
java.nio.channels.spi.AbstractInterruptibleChannel
| |||||||||||
|
From class
java.lang.Object
| |||||||||||
|
From interface
java.io.Closeable
| |||||||||||
|
From interface
java.nio.channels.Channel
| |||||||||||
|
From interface
java.nio.channels.InterruptibleChannel
| |||||||||||
Protected Constructors
protected AbstractSelectableChannel (SelectorProvider provider)
Initializes a new instance of this class.
Public Methods
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
- The blocking-mode lock object
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 | If true then this channel will be placed in blocking mode; if false then it will be placed non-blocking mode |
|---|
Returns
- This selectable channel
Throws
| IOException |
|---|
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
- true if, and only if, this channel is in blocking mode
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
- true if, and only if, this channel is registered
public final SelectionKey keyFor (Selector sel)
Retrieves the key representing the channel's registration with the given selector.
Returns
- 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
public final SelectorProvider provider ()
Returns the provider that created this channel.
Returns
- The provider that created this channel
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 | The selector with which this channel is to be registered |
|---|---|
| ops | The interest set for the resulting key |
| att | The attachment for the resulting key; may be null |
Returns
- A key representing the registration of this channel with the given selector
Throws
| ClosedChannelException |
|---|
Protected Methods
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 |
|---|
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 |
|---|
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.
Throws
| IOException | If an I/O error occurs |
|---|