root/gaphor/tags/gaphor-0.11.1/gaphor/core.py

"""
The Core module provides an entry point for Gaphor's core constructs.

An average module should only need to import this module.
"""

from gaphor.application import Application as _Application
from gaphor.transaction import Transaction, transactional
from gaphor.action import action, toggle_action, radio_action, build_action_group
from gaphor.i18n import _


class inject(object):
    """
    Simple descriptor for dependency injection.
    This is technically a wrapper around Application.get_service().

    Usage::

      class A(object):
        gui_manager = inject('gui_manager')
    """
    
    def __init__(self, name):
        self._name = name
        self._inj = None
        
    def __get__(self, obj, class_=None):
        """
        Resolve a dependency, but only if we're called from an object instance.
        """
        if not obj:
            return self
        if self._inj is None:
            self._inj = _Application.get_service(self._name)
        return self._inj


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