Package com.google.cloud.hadoop.util

Class AbstractGoogleAsyncWriteChannel<T>

  • Type Parameters:
    T - The type of the result of the completed upload operation.
    All Implemented Interfaces:
    Closeable, AutoCloseable, Channel, WritableByteChannel
    public abstract class AbstractGoogleAsyncWriteChannel<T>
extends Object
implements WritableByteChannel
    Skeletal implementation of a WritableByteChannel that executes an asynchronous upload operation and optionally handles the result.

    • Field Detail

      • logger

        protected static final com.google.common.flogger.GoogleLogger logger

      • uploadOperation

        protected Future<T> uploadOperation

      • cumulativeCrc32cHasher

        protected final com.google.common.hash.Hasher cumulativeCrc32cHasher

    • Constructor Detail

      • AbstractGoogleAsyncWriteChannel

        public AbstractGoogleAsyncWriteChannel​(ExecutorService threadPool,
                                       AsyncWriteChannelOptions channelOptions)
        Construct a new channel using the given ExecutorService to run background uploads.

    • Method Detail

      • handleResponse

        public void handleResponse​(T response)
                    throws IOException
        Handle the API response.

        This method is invoked after the upload has completed on the same thread that invokes close(). It can throw IOException if checksum matching is enabled and mismatched.

        Parameters:
        response - The API response object.
        Throws:
        IOException

      • isDirectUploadEnabled

        public boolean isDirectUploadEnabled()
        Returns true if direct media uploads are enabled.

      • write

        public int write​(ByteBuffer buffer)
          throws IOException
        Writes contents of the given buffer to this channel.

        Note: The data that one writes gets written to a pipe which must not block if the pipe has sufficient buffer space. A success code returned from this method does not mean that the specific data was successfully written to the underlying storage. It simply means that there is no error at present. The data upload may encounter an error on a separate thread. Such error is not ignored; it shows up as an exception during a subsequent call to write() or close(). The only way to be sure of successful upload is when the close() method returns successfully.

        Specified by:
        write in interface WritableByteChannel
        Parameters:
        buffer - buffer to write
        Throws:
        IOException - on IO error

      • isOpen

        public boolean isOpen()
        Tells whether this channel is open.
        Specified by:
        isOpen in interface Channel
        Returns:
        a value indicating whether this channel is open

      • close

        public void close()
           throws IOException
        Closes this channel.

        Note: The method returns only after all data has been successfully written to GCS or if there is a non-retry-able error.

        Specified by:
        close in interface AutoCloseable
        Specified by:
        close in interface Channel
        Specified by:
        close in interface Closeable
        Throws:
        IOException - on IO error

      • initialize

        public void initialize()
                throws IOException
        Initialize this channel object for writing.
        Throws:
        IOException

      • getResourceString

        protected abstract String getResourceString()