Package io.pravega.client.segment.impl

Interface SegmentInputStream

  • All Superinterfaces:
    java.lang.AutoCloseable
    public interface SegmentInputStream
extends java.lang.AutoCloseable
    Defines a InputStream for a single segment. Once created the offset must be provided by calling setOffset. The next read will proceed from this offset. Subsequent reads will read from where the previous one left off. (Parallel calls to read data will be serialized) Get offset can be used to store a location to revert back to that position in the future.

    • Method Summary

      All Methods Instance Methods Abstract Methods Default Methods 
      Modifier and Type Method Description
      int bytesInBuffer()
      Returns > 0 if read(ByteBuffer, long) can be invoked without blocking.
      void close()
      Closes this InputStream.
      java.util.concurrent.CompletableFuture<?> fillBuffer()
      Issue a request to asynchronously fill the buffer.
      long getOffset()
      Gets the current offset.
      Segment getSegmentId()  
      int read​(java.nio.ByteBuffer toFill, long timeout)
      If data is available this will copy bytes from an internal buffer into the buffer provided.
      default void setOffset​(long offset)
      Sets the offset for reading from the segment.
      void setOffset​(long offset, boolean resendRequest)
      Sets the offset for reading from the segment.

    • Method Detail

      • getSegmentId

        Segment getSegmentId()

      • setOffset

        default void setOffset​(long offset)
        Sets the offset for reading from the segment.
        Parameters:
        offset - The offset to set.

      • setOffset

        void setOffset​(long offset,
               boolean resendRequest)
        Sets the offset for reading from the segment.
        Parameters:
        offset - The offset to set.
        resendRequest - Resend the read request in-case there is an already pending read request for the offset.

      • getOffset

        long getOffset()
        Gets the current offset. (Passing this to setOffset in the future will reset reads to the current position in the segment.)
        Returns:
        The current offset.

      • read

        int read​(java.nio.ByteBuffer toFill,
         long timeout)
  throws EndOfSegmentException,
         SegmentTruncatedException
        If data is available this will copy bytes from an internal buffer into the buffer provided. If the provided buffer cannot be fully filled, it will return the data it has. If no data is available it will block until some becomes available up to the provided timeout. A caller can determine if this call will block in advance by calling bytesInBuffer(). If a caller wants to avoid blocking they call fillBuffer() and use the future to be notified when more data can be read without blocking.
        Parameters:
        toFill - the buffer to fill.
        timeout - the maximum time to block if no data is in memory.
        Returns:
        The number of bytes read.
        Throws:
        EndOfSegmentException - If no data could be read because the end of the segment was reached.
        SegmentTruncatedException - If the segment has been truncated beyond the current offset and data cannot be read.

      • fillBuffer

        java.util.concurrent.CompletableFuture<?> fillBuffer()
        Issue a request to asynchronously fill the buffer. To hopefully prevent future read(ByteBuffer, long) calls from blocking. Calling this multiple times is harmless.
        Returns:
        A future that will be completed when there is data available to read.

      • close

        void close()
        Closes this InputStream. No further methods may be called after close. This will free any resources associated with the InputStream.
        Specified by:
        close in interface java.lang.AutoCloseable

      • bytesInBuffer

        int bytesInBuffer()
        Returns > 0 if read(ByteBuffer, long) can be invoked without blocking. Returns 0 if read(ByteBuffer, long) will block. Returns -1 if a call to read will throw EndOfSegmentException.
        Returns:
        0 if data read is blocking.