collective.collectionfilter 1.0

Overloading GroupByCriteria

collective.collectionfilter.vocabularies.GroupByCriteria is a singleton, registered as global utility and used to provide a list of possible indices, which grouped values will provide your filter criteria.

It uses a data structure like this:

self._groupby = {
    it: {                   # Index name
        'index': it,           # Name of the index to use
        'metadata': it,        # Name of the metadata column to use
        'display_modifier': _  # Function to prepare the metadata column value for displaying
    }
    for it in metadata
}

As you can see, the standard GroupByCriteriaVocabulary implementation implies, that the index name is the same as the metadata column name. Also, we use the collective.collectionfilter message catalog as standard display_modifier (you can register translations under the collective.collectionfilter domain to translate index values).

If you need a special display_modifier, or index or metadata columns do not have the same identifier, you can modify this data structure. For that, register an adapter for IGroupByModifier, which adapts to the GroupByCriteria utility. Within this adapter, you can modify the already populated _groupby attribute (do not use the groupby, which is a property method and at this point hasn’t finished).

This is how.

Write an adapter:

# -*- coding: utf-8 -*-
from collective.collectionfilter.interfaces import IGroupByCriteria
from collective.collectionfilter.interfaces import IGroupByModifier
from zope.component import adapter
from zope.interface import implementer


@implementer(IGroupByModifier)
@adapter(IGroupByCriteria)
def groupby_modifier(groupby):
    groupby._groupby['Subject']['display_modifier'] = lambda x: x.upper()
    groupby._groupby['my_new_index'] = {
        'index': 'my_new_index',
        'metadata': 'my_new_index_metadata_colum',
        'display_modifier': lambda it: u'this is awesome: {0}'.format(it)
    }

Register the adapter:

<configure xmlns="http://namespaces.zope.org/zope">
  <adapter factory=".collectionfilter.groupby_modifier" name="modifier_1" />
</configure>

Done.

Your adapter is called by collective.collectionfilter.vocabularies.GroupByCriteria.groupby.

Author

• Johannes Raggam

• Peter Holzer

This package is based on collective.portlet.collectionfilter and collective.portlet.collectionbysubject.