Package org.apache.flink.runtime.io.disk.iomanager

Class AsynchronousFileIOChannel<T,​R extends org.apache.flink.runtime.io.disk.iomanager.IORequest>

    • Field Detail

      • closeLock

        protected final Object closeLock
        The lock that is used during closing to synchronize the thread that waits for all requests to be handled with the asynchronous I/O thread.

      • requestQueue

        protected final RequestQueue<R extends org.apache.flink.runtime.io.disk.iomanager.IORequest> requestQueue
        A request queue for submitting asynchronous requests to the corresponding IO worker thread.

      • requestsNotReturned

        protected final AtomicInteger requestsNotReturned
        An atomic integer that counts the number of requests that we still wait for to return.

      • resultHandler

        protected final RequestDoneCallback<T> resultHandler
        Handler for completed requests

      • exception

        protected volatile IOException exception
        An exception that was encountered by the asynchronous request handling thread.

      • closed

        protected volatile boolean closed
        Flag marking this channel as closed

    • Constructor Detail

      • AsynchronousFileIOChannel

        protected AsynchronousFileIOChannel​(FileIOChannel.ID channelID,
                                    RequestQueue<R> requestQueue,
                                    RequestDoneCallback<T> callback,
                                    boolean writeEnabled)
                             throws IOException
        Creates a new channel access to the path indicated by the given ID. The channel accepts buffers to be read/written and hands them to the asynchronous I/O thread. After being processed, the buffers are returned by adding the to the given queue.
        Parameters:
        channelID - The id describing the path of the file that the channel accessed.
        requestQueue - The queue that this channel hands its IO requests to.
        callback - The callback to be invoked when a request is done.
        writeEnabled - Flag describing whether the channel should be opened in read/write mode, rather than in read-only mode.
        Throws:
        IOException - Thrown, if the channel could no be opened.

    • Method Detail

      • close

        public void close()
           throws IOException
        Closes the channel and waits until all pending asynchronous requests are processed. The underlying FileChannel is closed even if an exception interrupts the closing.

        Important: the isClosed() method returns true immediately after this method has been called even when there are outstanding requests.

        Specified by:
        close in interface FileIOChannel
        Specified by:
        close in class AbstractFileIOChannel
        Throws:
        IOException - Thrown, if an I/O exception occurred while waiting for the buffers, or if the closing was interrupted.

      • closeAndDelete

        public void closeAndDelete()
                    throws IOException
        This method waits for all pending asynchronous requests to return. When the last request has returned, the channel is closed and deleted.

        Even if an exception interrupts the closing, such that not all request are handled, the underlying FileChannel is closed and deleted.

        Specified by:
        closeAndDelete in interface FileIOChannel
        Overrides:
        closeAndDelete in class AbstractFileIOChannel
        Throws:
        IOException - Thrown, if an I/O exception occurred while waiting for the buffers, or if the closing was interrupted.

      • checkErroneous

        public final void checkErroneous()
                          throws IOException
        Checks the exception state of this channel. The channel is erroneous, if one of its requests could not be processed correctly.
        Throws:
        IOException - Thrown, if the channel is erroneous. The thrown exception contains the original exception that defined the erroneous state as its cause.

      • handleProcessedBuffer

        protected final void handleProcessedBuffer​(T buffer,
                                           IOException ex)
        Handles a processed Buffer. This method is invoked by the asynchronous IO worker threads upon completion of the IO request with the provided buffer and/or an exception that occurred while processing the request for that buffer.
        Parameters:
        buffer - The buffer to be processed.
        ex - The exception that occurred in the I/O threads when processing the buffer's request.

      • registerAllRequestsProcessedListener

        protected boolean registerAllRequestsProcessedListener​(NotificationListener listener)
                                                throws IOException
        Registers a listener to be notified when all outstanding requests have been processed.

        New requests can arrive right after the listener got notified. Therefore, it is not safe to assume that the number of outstanding requests is still zero after a notification unless there was a close right before the listener got called.

        Returns true, if the registration was successful. A registration can fail, if there are no outstanding requests when trying to register a listener.

        Throws:
        IOException