org.apache.commons.io.input

Class ReadAheadInputStream

java.lang.Object

java.io.InputStream

org.apache.commons.io.input.ReadAheadInputStream

All Implemented Interfaces:

Closeable, AutoCloseable

public class ReadAheadInputStream
extends 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 and Description
ReadAheadInputStream(InputStream inputStream, int bufferSizeInBytes) Creates an instance with the specified buffer size and read-ahead threshold
ReadAheadInputStream(InputStream inputStream, int bufferSizeInBytes, ExecutorService executorService) Creates an instance with the specified buffer size and read-ahead threshold

Method Summary

Modifier and Type	Method and 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, read, reset

Methods inherited from class java.lang.Object

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

Constructor Detail

ReadAheadInputStream

public ReadAheadInputStream(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(InputStream inputStream,
                            int bufferSizeInBytes,
                            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 IOException

Overrides:

available in class InputStream

Throws:

IOException

close

public void close()
           throws IOException

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

Overrides:

close in class InputStream

Throws:

IOException

read

public int read()
         throws IOException

Specified by:

read in class InputStream

Throws:

IOException

read

public int read(byte[] b,
                int offset,
                int len)
         throws IOException

Overrides:

read in class InputStream

Throws:

IOException

skip

public long skip(long n)
          throws IOException

Overrides:

skip in class InputStream

Throws:

IOException