Source code for mxcubecore.HardwareObjects.abstract.AbstractShutter

#
#  Project: MXCuBE
#  https://github.com/mxcube
#
#  This file is part of MXCuBE software.
#
#  MXCuBE is free software: you can redistribute it and/or modify
#  it under the terms of the GNU Lesser General Public License as published by
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#  (at your option) any later version.
#
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#  GNU Lesser General Public License for more details.
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"""AbstractShutter class - interface for shutter type devices.
Define open/close methods and is_open property.
Overload BaseValueEnum
"""

import abc
from enum import (
    Enum,
    unique,
)

from mxcubecore.HardwareObjects.abstract.AbstractNState import AbstractNState

__copyright__ = """ Copyright 2016-2023 by the MXCuBE collaboration """
__license__ = "LGPLv3+"


@unique
class BaseValueEnum(Enum):
    """Defines only the compulsory values."""

    OPEN = "OPEN"
    CLOSED = "CLOSED"
    UNKNOWN = "UNKNOWN"


class AbstractShutter(AbstractNState):
    """Abstract base class for shutter type objects."""

    __metaclass__ = abc.ABCMeta
    VALUES = BaseValueEnum

    @property
    def is_open(self) -> bool:
        """Check if the shutter is open.
        Returns:
            (bool): True if open, False otherwise.
        """
        return self.get_value() == self.VALUES.OPEN

    @property
    def is_closed(self) -> bool:
        """Check if the shutter is closed.

        Note that it is not always true that ``is_closed != is_open``,
        it takes time to open and close the shutter.

        Many shutters can be in "moving" state.
        When in that state the shutter is both "not open" and "not closed".

        Returns:
            ``True`` if closed, ``False`` otherwise.
        """
        return self.get_value() == self.VALUES.CLOSED

    def open(self, timeout=None):
        """Open the shutter.
        Args:
            timeout(float): optional - timeout [s],
                            If timeout == 0: return at once and do not wait
                            if timeout is None: wait forever.
        """
        self.set_value(self.VALUES.OPEN, timeout=timeout)

    def close(self, timeout=None):
        """Close the shutter.
        Args:
            timeout(float): optional - timeout [s],
                            If timeout == 0: return at once and do not wait
                            if timeout is None: wait forever.
        """
        self.set_value(self.VALUES.CLOSED, timeout=timeout)