Class AbstractInterruptibleChannel

public abstract class AbstractInterruptibleChannel
extends Object
implements Channel, InterruptibleChannel

Base implementation class for interruptible channels.

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.

Constructors

AbstractInterruptibleChannel

protected AbstractInterruptibleChannel()

Initializes a new instance of this class.

Methods

close

public final void close()
                 throws IOException

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Channel

Specified by:

close in interface InterruptibleChannel

Throws:

IOException - If an I/O error occurs

implCloseChannel

protected abstract void implCloseChannel()
                                  throws IOException

Throws:

IOException - If an I/O error occurs while closing the channel

isOpen

public final boolean isOpen()

Description copied from interface: Channel

Tells whether or not this channel is open.

Specified by:

isOpen in interface Channel

Returns:

true if, and only if, this channel is open

begin

protected final void begin()

end

protected final void end(boolean completed)
                  throws AsynchronousCloseException

Parameters:

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 invoker

Throws:

AsynchronousCloseException - If the channel was asynchronously closed

ClosedByInterruptException - If the thread blocked in the I/O operation was interrupted