public abstract class AbstractSelectableChannel extends SelectableChannel
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.
Modifier | Constructor and Description |
---|---|
protected |
AbstractSelectableChannel(SelectorProvider provider)
Initializes a new instance of this class.
|
Modifier and Type | Method and Description |
---|---|
Object |
blockingLock()
Retrieves the object upon which the
configureBlocking and register methods synchronize. |
SelectableChannel |
configureBlocking(boolean block)
Adjusts this channel's blocking mode.
|
protected void |
implCloseChannel()
Closes this channel.
|
protected abstract void |
implCloseSelectableChannel()
Closes this selectable channel.
|
protected abstract void |
implConfigureBlocking(boolean block)
Adjusts this channel's blocking mode.
|
boolean |
isBlocking()
Tells whether or not every I/O operation on this channel will block
until it completes.
|
boolean |
isRegistered()
Tells whether or not this channel is currently registered with any
selectors.
|
SelectionKey |
keyFor(Selector sel)
Retrieves the key representing the channel's registration with the given
selector.
|
SelectorProvider |
provider()
Returns the provider that created this channel.
|
SelectionKey |
register(Selector sel,
int ops,
Object att)
Registers this channel with the given selector, returning a selection key.
|
register, validOps
begin, close, end, isOpen
protected AbstractSelectableChannel(SelectorProvider provider)
provider
- The provider that created this channelpublic final SelectorProvider provider()
provider
in class SelectableChannel
public final boolean isRegistered()
SelectableChannel
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.
isRegistered
in class SelectableChannel
public final SelectionKey keyFor(Selector sel)
SelectableChannel
keyFor
in class SelectableChannel
sel
- The selectorpublic final SelectionKey register(Selector sel, int ops, Object att) throws ClosedChannelException
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.
register
in class SelectableChannel
sel
- The selector with which this channel is to be registeredops
- The interest set for the resulting keyatt
- The attachment for the resulting key; may be nullClosedSelectorException
- If the selector is closedIllegalBlockingModeException
- If this channel is in blocking modeIllegalSelectorException
- If this channel was not created by the same provider
as the given selectorCancelledKeyException
- If this channel is currently registered with the given selector
but the corresponding key has already been cancelledIllegalArgumentException
- If a bit in the ops set does not correspond to an
operation that is supported by this channel, that is, if
set & ~validOps() != 0
ClosedChannelException
- If this channel is closedprotected final void implCloseChannel() throws IOException
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.
implCloseChannel
in class AbstractInterruptibleChannel
IOException
- If an I/O error occurs while closing the channelprotected abstract void implCloseSelectableChannel() throws IOException
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.
IOException
- If an I/O error occurspublic final boolean isBlocking()
SelectableChannel
If this channel is closed then the value returned by this method is not specified.
isBlocking
in class SelectableChannel
public final Object blockingLock()
SelectableChannel
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.blockingLock
in class SelectableChannel
public final SelectableChannel configureBlocking(boolean block) throws IOException
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.
configureBlocking
in class SelectableChannel
block
- If true then this channel will be placed in
blocking mode; if false then it will be placed
non-blocking modeClosedChannelException
- If this channel is closedIOException
- If an I/O error occursprotected abstract void implConfigureBlocking(boolean block) throws IOException
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.
block
- If true then this channel will be placed in
blocking mode; if false then it will be placed
non-blocking modeIOException
- If an I/O error occurs Submit a bug or feature
For further API reference and developer documentation, see Java SE Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.
Copyright © 1993, 2014, Oracle and/or its affiliates. All rights reserved.