Package org.apache.commons.io.input

Class ReadAheadInputStream

  • All Implemented Interfaces:
    java.io.Closeable, java.lang.AutoCloseable
    public class ReadAheadInputStream
extends java.io.InputStream
    Implements InputStream to asynchronously read ahead from an underlying input stream when a specified amount of data has been read from the current buffer. It does so by maintaining two buffers: an active buffer and a read ahead buffer. The active buffer contains data which should be returned when a read() call is issued. The read ahead buffer is used to asynchronously read from the underlying input stream. When the current active buffer is exhausted, we flip the two buffers so that we can start reading from the read ahead buffer without being blocked by disk I/O.

    This class was ported and adapted from Apache Spark commit 933dc6cb7b3de1d8ccaf73d124d6eb95b947ed19.

    Since:
    2.9.0

    • Constructor Summary

      Constructors 
      Constructor Description
      ReadAheadInputStream​(java.io.InputStream inputStream, int bufferSizeInBytes)
      Creates an instance with the specified buffer size and read-ahead threshold
      ReadAheadInputStream​(java.io.InputStream inputStream, int bufferSizeInBytes, java.util.concurrent.ExecutorService executorService)
      Creates an instance with the specified buffer size and read-ahead threshold

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      int available()  
      void close()  
      int read()  
      int read​(byte[] b, int offset, int len)  
      long skip​(long n)  

      • Methods inherited from class java.io.InputStream

        mark, markSupported, nullInputStream, read, readAllBytes, readNBytes, readNBytes, reset, transferTo

      • Methods inherited from class java.lang.Object

        equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

    • Constructor Detail

      • ReadAheadInputStream

        public ReadAheadInputStream​(java.io.InputStream inputStream,
                            int bufferSizeInBytes)
        Creates an instance with the specified buffer size and read-ahead threshold
        Parameters:
        inputStream - The underlying input stream.
        bufferSizeInBytes - The buffer size.

      • ReadAheadInputStream

        public ReadAheadInputStream​(java.io.InputStream inputStream,
                            int bufferSizeInBytes,
                            java.util.concurrent.ExecutorService executorService)
        Creates an instance with the specified buffer size and read-ahead threshold
        Parameters:
        inputStream - The underlying input stream.
        bufferSizeInBytes - The buffer size.
        executorService - An executor service for the read-ahead thread.

    • Method Detail

      • available

        public int available()
              throws java.io.IOException
        Overrides:
        available in class java.io.InputStream
        Throws:
        java.io.IOException

      • close

        public void close()
           throws java.io.IOException
        Specified by:
        close in interface java.lang.AutoCloseable
        Specified by:
        close in interface java.io.Closeable
        Overrides:
        close in class java.io.InputStream
        Throws:
        java.io.IOException

      • read

        public int read()
         throws java.io.IOException
        Specified by:
        read in class java.io.InputStream
        Throws:
        java.io.IOException

      • read

        public int read​(byte[] b,
                int offset,
                int len)
         throws java.io.IOException
        Overrides:
        read in class java.io.InputStream
        Throws:
        java.io.IOException

      • skip

        public long skip​(long n)
          throws java.io.IOException
        Overrides:
        skip in class java.io.InputStream
        Throws:
        java.io.IOException