Method Calls on InitializationΒΆ

New in version 2.6.


This is an experimental support in Imagination 2.6 and designed to work only with Python 3.5 or newer.

In some situations, you may want to call some methods upon successful initialization/instantiation.

Suppose we have a code like the following.

import threading

class Counter(object):
    def __init__(self):
        self.debug_mode = False
        self.ping_count = 0

    def ping(self):
        self.ping_count += 1

    def enable_debug_mode(enabled):
        self.debug_mode = enabled or False

class App(object):
    def __init__(self):
        self.counter = None

    def set_counter(self, counter):
        self.counter = counter

    def listen(self):
        while True:

    def passively_listen(self):
        listener = threading.Thread(target = self.listen, daemon = True)

We want to define entities in a way that:

  • app will start listening in the background with passively_listen upon instantiation but we DO NOT want to call the method inside __init__.
<entity id="app" class="app.App">
    <call method="passively_listen"/>
  • Once the entity counter is instantiated, the main container will call the method set_counter from the entity app with itself.
<entity id="counter" class="app.Counter">
    <call method="enable_debug_mode">
        <param type="bool" name="enabled">true</param>
    <call method="set_counter" from="app">
        <param type="entity" name="counter">self</param>
        <!-- NOTE "self" refers to "counter". -->