serial/serialjava.py

#!jython
#
# Backend Jython with JavaComm
#
# This file is part of pySerial. https://github.com/pyserial/pyserial
# (C) 2002-2015 Chris Liechti <cliechti@gmx.net>
#
# SPDX-License-Identifier:    BSD-3-Clause

from __future__ import absolute_import

from serial.serialutil import *


def my_import(name):
    mod = __import__(name)
    components = name.split('.')
    for comp in components[1:]:
        mod = getattr(mod, comp)
    return mod


def detect_java_comm(names):
    """try given list of modules and return that imports"""
    for name in names:
        try:
            mod = my_import(name)
            mod.SerialPort
            return mod
        except (ImportError, AttributeError):
            pass
    raise ImportError("No Java Communications API implementation found")


# Java Communications API implementations
# http://mho.republika.pl/java/comm/

comm = detect_java_comm([
    'javax.comm',  # Sun/IBM
    'gnu.io',      # RXTX
])


def device(portnumber):
    """Turn a port number into a device name"""
    enum = comm.CommPortIdentifier.getPortIdentifiers()
    ports = []
    while enum.hasMoreElements():
        el = enum.nextElement()
        if el.getPortType() == comm.CommPortIdentifier.PORT_SERIAL:
            ports.append(el)
    return ports[portnumber].getName()


class Serial(SerialBase):
    """\
    Serial port class, implemented with Java Communications API and
    thus usable with jython and the appropriate java extension.
    """

    def open(self):
        """\
        Open port with current settings. This may throw a SerialException
        if the port cannot be opened.
        """
        if self._port is None:
            raise SerialException("Port must be configured before it can be used.")
        if self.is_open:
            raise SerialException("Port is already open.")
        if type(self._port) == type(''):      # strings are taken directly
            portId = comm.CommPortIdentifier.getPortIdentifier(self._port)
        else:
            portId = comm.CommPortIdentifier.getPortIdentifier(device(self._port))     # numbers are transformed to a comport id obj
        try:
            self.sPort = portId.open("python serial module", 10)
        except Exception as msg:
            self.sPort = None
            raise SerialException("Could not open port: %s" % msg)
        self._reconfigurePort()
        self._instream = self.sPort.getInputStream()
        self._outstream = self.sPort.getOutputStream()
        self.is_open = True

    def _reconfigurePort(self):
        """Set communication parameters on opened port."""
        if not self.sPort:
            raise SerialException("Can only operate on a valid port handle")

        self.sPort.enableReceiveTimeout(30)
        if self._bytesize == FIVEBITS:
            jdatabits = comm.SerialPort.DATABITS_5
        elif self._bytesize == SIXBITS:
            jdatabits = comm.SerialPort.DATABITS_6
        elif self._bytesize == SEVENBITS:
            jdatabits = comm.SerialPort.DATABITS_7
        elif self._bytesize == EIGHTBITS:
            jdatabits = comm.SerialPort.DATABITS_8
        else:
            raise ValueError("unsupported bytesize: %r" % self._bytesize)

        if self._stopbits == STOPBITS_ONE:
            jstopbits = comm.SerialPort.STOPBITS_1
        elif self._stopbits == STOPBITS_ONE_POINT_FIVE:
            jstopbits = comm.SerialPort.STOPBITS_1_5
        elif self._stopbits == STOPBITS_TWO:
            jstopbits = comm.SerialPort.STOPBITS_2
        else:
            raise ValueError("unsupported number of stopbits: %r" % self._stopbits)

        if self._parity == PARITY_NONE:
            jparity = comm.SerialPort.PARITY_NONE
        elif self._parity == PARITY_EVEN:
            jparity = comm.SerialPort.PARITY_EVEN
        elif self._parity == PARITY_ODD:
            jparity = comm.SerialPort.PARITY_ODD
        elif self._parity == PARITY_MARK:
            jparity = comm.SerialPort.PARITY_MARK
        elif self._parity == PARITY_SPACE:
            jparity = comm.SerialPort.PARITY_SPACE
        else:
            raise ValueError("unsupported parity type: %r" % self._parity)

        jflowin = jflowout = 0
        if self._rtscts:
            jflowin |= comm.SerialPort.FLOWCONTROL_RTSCTS_IN
            jflowout |= comm.SerialPort.FLOWCONTROL_RTSCTS_OUT
        if self._xonxoff:
            jflowin |= comm.SerialPort.FLOWCONTROL_XONXOFF_IN
            jflowout |= comm.SerialPort.FLOWCONTROL_XONXOFF_OUT

        self.sPort.setSerialPortParams(self._baudrate, jdatabits, jstopbits, jparity)
        self.sPort.setFlowControlMode(jflowin | jflowout)

        if self._timeout >= 0:
            self.sPort.enableReceiveTimeout(int(self._timeout*1000))
        else:
            self.sPort.disableReceiveTimeout()

    def close(self):
        """Close port"""
        if self.is_open:
            if self.sPort:
                self._instream.close()
                self._outstream.close()
                self.sPort.close()
                self.sPort = None
            self.is_open = False

    #  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -

    @property
    def in_waiting(self):
        """Return the number of characters currently in the input buffer."""
        if not self.sPort:
            raise portNotOpenError
        return self._instream.available()

    def read(self, size=1):
        """\
        Read size bytes from the serial port. If a timeout is set it may
        return less characters as requested. With no timeout it will block
        until the requested number of bytes is read.
        """
        if not self.sPort:
            raise portNotOpenError
        read = bytearray()
        if size > 0:
            while len(read) < size:
                x = self._instream.read()
                if x == -1:
                    if self.timeout >= 0:
                        break
                else:
                    read.append(x)
        return bytes(read)

    def write(self, data):
        """Output the given string over the serial port."""
        if not self.sPort:
            raise portNotOpenError
        if not isinstance(data, (bytes, bytearray)):
            raise TypeError('expected %s or bytearray, got %s' % (bytes, type(data)))
        self._outstream.write(data)
        return len(data)

    def reset_input_buffer(self):
        """Clear input buffer, discarding all that is in the buffer."""
        if not self.sPort:
            raise portNotOpenError
        self._instream.skip(self._instream.available())

    def reset_output_buffer(self):
        """\
        Clear output buffer, aborting the current output and
        discarding all that is in the buffer.
        """
        if not self.sPort:
            raise portNotOpenError
        self._outstream.flush()

    def send_break(self, duration=0.25):
        """Send break condition. Timed, returns to idle state after given duration."""
        if not self.sPort:
            raise portNotOpenError
        self.sPort.sendBreak(duration*1000.0)

    def _update_break_state(self):
        """Set break: Controls TXD. When active, to transmitting is possible."""
        if self.fd is None:
            raise portNotOpenError
        raise SerialException("The _update_break_state function is not implemented in java.")

    def _update_rts_state(self):
        """Set terminal status line: Request To Send"""
        if not self.sPort:
            raise portNotOpenError
        self.sPort.setRTS(self._rts_state)

    def _update_dtr_state(self):
        """Set terminal status line: Data Terminal Ready"""
        if not self.sPort:
            raise portNotOpenError
        self.sPort.setDTR(self._dtr_state)

    @property
    def cts(self):
        """Read terminal status line: Clear To Send"""
        if not self.sPort:
            raise portNotOpenError
        self.sPort.isCTS()

    @property
    def dsr(self):
        """Read terminal status line: Data Set Ready"""
        if not self.sPort:
            raise portNotOpenError
        self.sPort.isDSR()

    @property
    def ri(self):
        """Read terminal status line: Ring Indicator"""
        if not self.sPort:
            raise portNotOpenError
        self.sPort.isRI()

    @property
    def cd(self):
        """Read terminal status line: Carrier Detect"""
        if not self.sPort:
            raise portNotOpenError
        self.sPort.isCD()