For example, DS_C_FILTER inherits the OM attributes from its superclass OM_C_OBJECT, as do all OM classes. OM_C_OBJECT, as defined in Object Management Package, has one OM attribute, OM_CLASS, which has the value of an object identifier string that identifies the numeric representation of the object's OM class. DS_C_FILTER, on the other hand, has several OM attributes.
The purpose of DS_C_FILTER is to select or reject an object on the basis of information in its directory entry. It has the following OM attributes:
· DS_FILTER_ITEMS
· DS_FILTERS
· DS_FILTER_TYPE
Two of these OM attributes, DS_FILTER_ITEMS and DS_FILTERS, have values that are OM object classes themselves. The value of the OM attribute DS_FILTER_ITEMS is DS_C_FILTER_ITEM, which is an OM class. DS_C_FILTER_ITEM is a component of a filter and defines the nature of the filter. The value of the OM attribute DS_FILTERS is DS_C_FILTER, an OM class. Thus, DS_FILTERS defines a collection of filters. The OM attribute DS_FILTER_TYPE has a value that is an enumerated type, which takes one of the values DS_AND, DS_OR, or DS_NOT.
Refer to the figure, OM Class DS_C_FILTER, for a description of the relationship of DS_C_FILTER to its superclass OM_C_OBJECT and its attributes.