public abstract class AbstractInterruptibleChannel extends Object implements Channel, InterruptibleChannel
This class encapsulates the low-level machinery required to implement
the asynchronous closing and interruption of channels. A concrete channel
class must invoke the begin and end methods
before and after, respectively, invoking an I/O operation that might block
indefinitely. In order to ensure that the end method is always
invoked, these methods should be used within a
try ... finally block:
boolean completed = false;
try {
begin();
completed = ...; // Perform blocking I/O operation
return ...; // Return result
} finally {
end(completed);
} The completed argument to the end method tells
whether or not the I/O operation actually completed, that is, whether it had
any effect that would be visible to the invoker. In the case of an
operation that reads bytes, for example, this argument should be
true if, and only if, some bytes were actually transferred into the
invoker's target buffer.
A concrete channel class must also implement the implCloseChannel method in such a way that if it is
invoked while another thread is blocked in a native I/O operation upon the
channel then that operation will immediately return, either by throwing an
exception or by returning normally. If a thread is interrupted or the
channel upon which it is blocked is asynchronously closed then the channel's
end method will throw the appropriate exception.
This class performs the synchronization required to implement the Channel specification. Implementations of the implCloseChannel method need not synchronize against
other threads that might be attempting to close the channel.
| Modifier | Constructor and Description |
|---|---|
protected |
AbstractInterruptibleChannel()
Initializes a new instance of this class.
|
| Modifier and Type | Method and Description |
|---|---|
protected void |
begin()
Marks the beginning of an I/O operation that might block indefinitely.
|
void |
close()
Closes this channel.
|
protected void |
end(boolean completed)
Marks the end of an I/O operation that might block indefinitely.
|
protected abstract void |
implCloseChannel()
Closes this channel.
|
boolean |
isOpen()
Tells whether or not this channel is open.
|
protected AbstractInterruptibleChannel()
public final void close()
throws IOException
If the channel has already been closed then this method returns
immediately. Otherwise it marks the channel as closed and then invokes
the implCloseChannel method in order to
complete the close operation.
close in interface Closeableclose in interface AutoCloseableclose in interface Channelclose in interface InterruptibleChannelIOException - If an I/O error occursprotected abstract void implCloseChannel()
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 occurs while closing the channelpublic final boolean isOpen()
Channelprotected final void begin()
protected final void end(boolean completed)
throws AsynchronousCloseException
This method should be invoked in tandem with the begin method, using a try ... finally block
as shown above, in order to implement asynchronous
closing and interruption for this channel.
completed - true if, and only if, the I/O operation completed
successfully, that is, had some effect that would be visible to
the operation's invokerAsynchronousCloseException - If the channel was asynchronously closedClosedByInterruptException - If the thread blocked in the I/O operation was interrupted 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.
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