Interface HelperTransport

All Known Implementing Classes:
NativeSubprocessTransport
public interface HelperTransport

The abstraction over the cn1-ble-helper child process's standard I/O. HelperBleBackend speaks the line-delimited JSON protocol through this seam only, so a host that has no operating-system process API (the native Windows/Linux ports, which reach the subprocess through a native bridge) can supply its own implementation, while the JavaSE simulator supplies a subprocess-backed one.

All methods are called from at most one reader thread and the caller thread; implementations must make readLine()/writeLine(String) and close()/isAlive() safe for that pairing.

  • Method Summary

    Modifier and Type
    Method
    Description
    void
    close()
    Releases the transport and terminates the child process.
    boolean
    isAlive()
    True while the child process is running.
    String
    readLine()
    Reads one line of the helper's standard output, blocking until a line is available.
    void
    start(List<String> command)
    Launches the helper.
    void
    writeLine(String line)
    Writes one command line to the helper's standard input.

  • Method Details

    • start

      void start(List<String> command) throws IOException
      Launches the helper. command is the launch command line (the resolved helper binary path, optionally with arguments). A transport that was pre-configured with its own command by its factory may ignore a null argument and launch that instead.
      Parameters:
      command - the launch command line, or null to use the transport's pre-configured command
      Throws:
      IOException - when the child process cannot be started

    • readLine

      String readLine() throws IOException
      Reads one line of the helper's standard output, blocking until a line is available.
      Returns:
      the next line without its terminator, or null at end of stream (the helper closed stdout / exited)
      Throws:
      IOException - when the pipe fails

    • writeLine

      void writeLine(String line) throws IOException
      Writes one command line to the helper's standard input. The line terminator is appended by the transport and the stream is flushed.
      Parameters:
      line - the single-line JSON command, without a terminator
      Throws:
      IOException - when the pipe fails

    • close

      void close()
      Releases the transport and terminates the child process.

    • isAlive

      boolean isAlive()
      True while the child process is running.