# $Id: IIndexable.py,v 1.1 2006/07/21 08:42:14 marcusva Exp $
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# Copyright (c) 2004-2006, Marcus von Appen
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"""Abstract indexing interface for easy navigation through object lists."""

class IIndexable (object):
    """IIndexable () -> IIndexable

    Abstract class providing methods for easy navigation.

    The IIndexable interface class provides a minimal method set, a
    class should implement to allow easy navigation through objects.

    Objects can be added to the indexing system using the add_index()
    method and be removed by the counterpart remove_index().

    To cycle through the objects, the switch_index() method has to be
    implemented by an inheriting class. This causes - dependant on the
    implementation - another object to get the navigation focus
    (preferably the next object in the logical index list).
    """
    def add_index (self, *objects):
        """I.add_index (...) -> None

        Adds one or more objects to the indexing system.

        This method has to be implemented by inherited classes.
        """
        raise NotImplementedError

    def remove_index (self, *objects):
        """I.remove_index (...) -> None

        Removes one or more objects from the indexing system.

        This method has to be implemented by inherited classes.
        """
        raise NotImplementedError

    def switch_index (self):
        """I.switch_index () -> None

        Passes the input focus to another object from the list.

        This method has to be implemented by inherited classes.
        """
        raise NotImplementedError

    def update_index (self, *objects):
        """I.update_index () -> None

        Updates the index for one or more objects.

        This method has to be implemented by inherited classes.
        """
        raise NotImplementedError