Package nz.org.riskscape.engine.cli

Class InterruptibleReadline

java.lang.Object
nz.org.riskscape.engine.cli.InterruptibleReadline
public class InterruptibleReadline extends Object

Has a routine for reading a line of input from the console in a way that shouldn't block, even though it uses blocking I/O calls. That allows the reading thread to be interrupted, which we can use to support ctrl-c while a user is entering input.

This is implemented by checking InputStream.available() and then sleeping for a small interval when nothing can be read. A human shouldn't be able to detect the pause, but it's still long enough to avoid spin-locking a CPU.

  • Constructor Details

    • InterruptibleReadline

      public InterruptibleReadline()

  • Method Details

    • readline

      public static String readline(InputStream stdin) throws IOException, InterruptedException

      Read a line of input from an input stream, presumably stdin.

      Parameters:
      stdin - An InputStream to read a line from. Note that if stdin doesn't support mark (InputStream#markSupported returns true), and it is wrapped to force it to support it, then you must make sure all other users or stdin use the wrapped/buffered version, or they may miss the first character after a call to readline if '\r's appear in the stream.
      Returns:
      the string that was read, with the line terminator removed.
      Throws:
      IOException - if there was an io error reading from stdin
      InterruptedException - if the thread was interrupted while waiting to receive keypresses