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:

  • Field Details

    • BYTE_ARRAY_1

      private static final ThreadLocal<byte[]> BYTE_ARRAY_1

    • stateChangeLock

      private final ReentrantLock stateChangeLock

    • activeBuffer

      private ByteBuffer activeBuffer

    • readAheadBuffer

      private ByteBuffer readAheadBuffer

    • endOfStream

      private boolean endOfStream

    • readInProgress

      private boolean readInProgress

    • readAborted

      private boolean readAborted

    • readException

      private Throwable readException

    • isClosed

      private boolean isClosed

    • isUnderlyingInputStreamBeingClosed

      private boolean isUnderlyingInputStreamBeingClosed

    • isReading

      private boolean isReading

    • isWaiting

      private final AtomicBoolean isWaiting

    • executorService

      private final ExecutorService executorService

    • shutdownExecutorService

      private final boolean shutdownExecutorService

    • asyncReadComplete

      private final Condition asyncReadComplete

  • 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.

    • ReadAheadInputStream

      private ReadAheadInputStream(InputStream inputStream, int bufferSizeInBytes, ExecutorService executorService, boolean shutdownExecutorService)
      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.
      shutdownExecutorService - Whether or not to shut down the given ExecutorService on close.

  • Method Details