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import logging
logger = logging.getLogger(__name__)
class ElementsManager(object):
"""
A class managing a collection of 'elements'.
Those elements are expected to be objects that
* can be compared for equality against each other
* have the attribute .identifier
"""
DEFAULT_ELEMENTS = []
ELEMENT_NAME = "element"
def __init__(self, elements=None):
if elements:
self._elements = elements
else:
self._elements = self.DEFAULT_ELEMENTS
def register(self, element, pos=-1):
if element not in self._elements:
if pos == -1: pos = len(self._labels)
self._labels.insert(len(self._labels), label)
else:
logger.warn("Won't register %s as it's already present: %s", self.ELEMENT_NAME, element)
def deregister(self, element):
if element in self._elements:
self._elements.remove(element)
else:
logger.warn("Trying to deregister a %s that's not registered currently: %s", self.ELEMENT_NAME, label)
def iter_identifiers(self):
for element in self._elements:
yield element.identifier
def iter_elements(self):
for element in self._elements:
yield element
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