Class NonBlockingInputStream

java.lang.Object
java.io.InputStream
jline.internal.NonBlockingInputStream
All Implemented Interfaces:
Closeable, AutoCloseable, Runnable
public class NonBlockingInputStream extends InputStream implements Runnable
This class wraps a regular input stream and allows it to appear as if it is non-blocking; that is, reads can be performed against it that timeout if no data is seen for a period of time. This effect is achieved by having a separate thread perform all non-blocking read requests and then waiting on the thread to complete.

VERY IMPORTANT NOTES

  • This class is not thread safe. It expects at most one reader.
  • The shutdown() method must be called in order to shut down the thread that handles blocking I/O.
Since:
2.7

  • Field Details

    • in

      private InputStream in

    • ch

      private int ch

    • threadIsReading

      private boolean threadIsReading

    • isShutdown

      private boolean isShutdown

    • exception

      private IOException exception

    • nonBlockingEnabled

      private boolean nonBlockingEnabled

  • Constructor Details

    • NonBlockingInputStream

      public NonBlockingInputStream(InputStream in, boolean isNonBlockingEnabled)
      Creates a NonBlockingInputStream out of a normal blocking stream. Note that this call also spawn a separate thread to perform the blocking I/O on behalf of the thread that is using this class. The shutdown() method must be called in order to shut this thread down.
      Parameters:
      in - The input stream to wrap
      isNonBlockingEnabled - If true, then the non-blocking methods read(long) and peek(long) will be available and, more importantly, the thread will be started to provide support for the feature. If false, then this class acts as a clean-passthru for the underlying I/O stream and provides very little overhead.

  • Method Details

    • shutdown

      public void shutdown()
      Shuts down the thread that is handling blocking I/O. Note that if the thread is currently blocked waiting for I/O it will not actually shut down until the I/O is received. Shutting down the I/O thread does not prevent this class from being used, but causes the non-blocking methods to fail if called and causes isNonBlockingEnabled() to return false.

    • isNonBlockingEnabled

      public boolean isNonBlockingEnabled()
      Non-blocking is considered enabled if the feature is enabled and the I/O thread has not been shut down.
      Returns:
      true if non-blocking mode is enabled.

    • close

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

    • read

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

    • peek

      public int peek(long timeout) throws IOException
      Peeks to see if there is a byte waiting in the input stream without actually consuming the byte.
      Parameters:
      timeout - The amount of time to wait, 0 == forever
      Returns:
      -1 on eof, -2 if the timeout expired with no available input or the character that was read (without consuming it).
      Throws:
      IOException

    • read

      public int read(long timeout) throws IOException
      Attempts to read a character from the input stream for a specific period of time.
      Parameters:
      timeout - The amount of time to wait for the character
      Returns:
      The character read, -1 if EOF is reached, or -2 if the read timed out.
      Throws:
      IOException

    • read

      private int read(long timeout, boolean isPeek) throws IOException
      Attempts to read a character from the input stream for a specific period of time.
      Parameters:
      timeout - The amount of time to wait for the character
      Returns:
      The character read, -1 if EOF is reached, or -2 if the read timed out.
      Throws:
      IOException

    • read

      public int read(byte[] b, int off, int len) throws IOException
      This version of read() is very specific to jline's purposes, it will always always return a single byte at a time, rather than filling the entire buffer.
      Overrides:
      read in class InputStream
      Throws:
      IOException

    • run

      public void run()
      Specified by:
      run in interface Runnable