""" Pipeline implementation

$Id$
"""

from zope.interface import implements
from pipelines.interfaces import IPipeline, AbortPipelineException

## add completed, aborted, etc?
class PipeState:
    pass

class Pipeline:
    """ A pipeline is a collection of filters, which are notified in order.
    """
    implements(IPipeline)

    def __init__(self, filters=()):
        self._filters = tuple(filters)

    def __call__(self, data):
        """ Process our pipeline, allowing each filter to handle 'data'.
        """
        self.processFilters(data)

    def processFilters(self, data):
        """ Process our pipeline, allowing each filter to handle 'data'.
        """
        state = PipeState()
        for filter in self._filters:
            try:
                filter(data, state)
            except AbortPipelineException:
                break
        return state