Package org.eclipse.ecf.provider.filetransfer.util

Class PollingInputStream

  • All Implemented Interfaces:
    Closeable, AutoCloseable
    public class PollingInputStream
extends FilterInputStream
    Polls a progress monitor periodically and handles timeouts over extended durations. For this class to be effective, a high numAttempts should be specified, and the underlying stream should time out frequently on reads (every second or so). Supports resuming partially completed operations after an InterruptedIOException if the underlying stream does. Check the bytesTransferred field to determine how much of the operation completed; conversely, at what point to resume.
    Since:
    3.0

    • Constructor Detail

      • PollingInputStream

        public PollingInputStream​(InputStream in,
                          int numAttempts,
                          org.eclipse.core.runtime.IProgressMonitor monitor)
        Creates a new polling input stream.
        Parameters:
        in - the underlying input stream
        numAttempts - the number of attempts before issuing an InterruptedIOException, if 0, retries indefinitely until canceled
        monitor - the progress monitor to be polled for cancellation

      • PollingInputStream

        public PollingInputStream​(InputStream in,
                          int numAttempts,
                          org.eclipse.core.runtime.IProgressMonitor monitor,
                          String readTimeoutMessage,
                          String closeTimeoutMessage)
        Creates a new polling input stream.
        Parameters:
        in - the underlying input stream
        numAttempts - the number of attempts before issuing an InterruptedIOException, if 0, retries indefinitely until canceled
        monitor - the progress monitor to be polled for cancellation
        readTimeoutMessage - message to go with InteruptedIOException if read timeout
        closeTimeoutMessage - message to go with InteruptedIOException if close timeout
        Since:
        3.1

    • Method Detail

      • close

        public void close()
           throws InterruptedIOException
        Wraps the underlying stream's method. It may be important to wait for an input stream to be closed because it holds an implicit lock on a system resource (such as a file) while it is open. Closing a stream may take time if the underlying stream is still servicing a previous request.
        Specified by:
        close in interface AutoCloseable
        Specified by:
        close in interface Closeable
        Overrides:
        close in class FilterInputStream
        Throws:
        org.eclipse.core.runtime.OperationCanceledException - if the progress monitor is canceled
        InterruptedIOException - if the underlying operation times out numAttempts times

      • read

        public int read()
         throws IOException
        Wraps the underlying stream's method.
        Overrides:
        read in class FilterInputStream
        Returns:
        the next byte of data, or -1 if the end of the stream is reached.
        Throws:
        org.eclipse.core.runtime.OperationCanceledException - if the progress monitor is canceled
        InterruptedIOException - if the underlying operation times out numAttempts times and no data was received, bytesTransferred will be zero
        IOException - if an i/o error occurs

      • read

        public int read​(byte[] buffer,
                int off,
                int len)
         throws IOException
        Wraps the underlying stream's method.
        Overrides:
        read in class FilterInputStream
        Parameters:
        buffer - - the buffer into which the data is read.
        off - - the start offset of the data.
        len - - the maximum number of bytes read.
        Returns:
        the total number of bytes read into the buffer, or -1 if there is no more data because the end of the stream has been reached.
        Throws:
        org.eclipse.core.runtime.OperationCanceledException - if the progress monitor is canceled
        InterruptedIOException - if the underlying operation times out numAttempts times and no data was received, bytesTransferred will be zero
        IOException - if an i/o error occurs

      • skip

        public long skip​(long count)
          throws IOException
        Wraps the underlying stream's method.
        Overrides:
        skip in class FilterInputStream
        Parameters:
        count - - the number of bytes to be skipped.
        Returns:
        the actual number of bytes skipped.
        Throws:
        org.eclipse.core.runtime.OperationCanceledException - if the progress monitor is canceled
        InterruptedIOException - if the underlying operation times out numAttempts times and no data was received, bytesTransferred will be zero
        IOException - if an i/o error occurs

      • readPendingInput

        protected void readPendingInput()
                         throws IOException
        Reads any pending input from the input stream so that the stream can savely be closed.
        Throws:
        IOException - if some problem reading

      • setIsCancellable

        public void setIsCancellable​(boolean cancellable)
        Called to set whether cancellation will be checked by this stream. Turning cancellation checking off can be very useful for protecting critical portions of a protocol that shouldn't be interrupted. For example, it is often necessary to protect login sequences.
        Parameters:
        cancellable - a flag controlling whether this stream will check for cancellation.