Package org.apache.commons.io.input

Class ReadAheadInputStream

java.lang.Object

java.io.InputStream

java.io.FilterInputStream

org.apache.commons.io.input.ReadAheadInputStream

All Implemented Interfaces:

Closeable, AutoCloseable

public class ReadAheadInputStream
extends FilterInputStream

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.

To build an instance, use ReadAheadInputStream.Builder.

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

Since:

2.9.0

See Also:

• ReadAheadInputStream.Builder

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	ReadAheadInputStream.Builder	Builds a new ReadAheadInputStream.

Field Summary

Fields inherited from class java.io.FilterInputStream

in

Constructor Summary

Constructors

Constructor	Description
ReadAheadInputStream(InputStream inputStream, int bufferSizeInBytes)	Deprecated. Use builder(), ReadAheadInputStream.Builder, and ReadAheadInputStream.Builder.get()
ReadAheadInputStream(InputStream inputStream, int bufferSizeInBytes, ExecutorService executorService)	Deprecated. Use builder(), ReadAheadInputStream.Builder, and ReadAheadInputStream.Builder.get()

Method Summary

Modifier and Type	Method	Description
int	available()
static ReadAheadInputStream.Builder	builder()	Constructs a new ReadAheadInputStream.Builder.
void	close()
int	read()
int	read(byte[] b, int offset, int len)
long	skip(long n)

Methods inherited from class java.io.FilterInputStream

mark, markSupported, read, reset

Methods inherited from class java.lang.Object

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

Constructor Details

ReadAheadInputStream

@Deprecated
public ReadAheadInputStream(InputStream inputStream,
 int bufferSizeInBytes)

Deprecated.

Use builder(), ReadAheadInputStream.Builder, and ReadAheadInputStream.Builder.get()

Constructs an instance with the specified buffer size and read-ahead threshold

Parameters:

inputStream - The underlying input stream.

bufferSizeInBytes - The buffer size.

ReadAheadInputStream

@Deprecated
public ReadAheadInputStream(InputStream inputStream,
 int bufferSizeInBytes,
 ExecutorService executorService)

Deprecated.

Use builder(), ReadAheadInputStream.Builder, and ReadAheadInputStream.Builder.get()

Constructs 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 Details

builder

public static ReadAheadInputStream.Builder builder()

Constructs a new ReadAheadInputStream.Builder.

Returns:

a new ReadAheadInputStream.Builder.

Since:

2.12.0

available

public int available()
              throws IOException

Overrides:

available in class FilterInputStream

Throws:

IOException

close

public void close()
           throws IOException

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Closeable

Overrides:

close in class FilterInputStream

Throws:

IOException

read

public int read()
         throws IOException

Overrides:

read in class FilterInputStream

Throws:

IOException

read

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

Overrides:

read in class FilterInputStream

Throws:

IOException

skip

public long skip(long n)
          throws IOException

Overrides:

skip in class FilterInputStream

Throws:

IOException