Windchill ESI services provides two classes that support Alternate Item Groups. The classes are not intended to be extended by customizers, but they may be used by customizers. These are the classes:

AlternateItemGroup is a subclass of ObjectToObjectLink and is therefore a persistable object. An AlternateItemGroup object links a WTPart (the BOM assembly part) to a WTPartMaster (the BOM component). The AlternateItemGroup object is created when a BOM is published. The object is not available to Windchill GUI clients. It has these attributes with public getters and setters:

The unique alternate item group number. This is stored as an integer, but rendered as a two-byte string. The string is the base-36 value of the number.

The line number of the usage link that this AlternateItemGroup object describes. If line numbers are not supported, the value of this attribute is –1.

The AlternateItemGroupMgr class provides several useful utility methods for handling AlternateItemGroup objects. These are the available methods of the class:

Creates an AlternateItemGroup object in database based upon the given PartUsageInfo object.

Returns a collection of the AlternateItemGroup objects that are associated to an assembly part.

Returns an AlternateItemGroup, if one exists in the database. Uses a WTPart to identify the assembly. Uses a PartUsageInfo to identify the line number and component on the assembly.

Checks whether substitutes exist on a part usage link associated to a PartUsageInfo object.

Returns an alternate item group, based on the assembly part iteration and the part master that are passed in. If a line number is passed in, this is used as well in the query that fetches the alternate item group.

Returns an AlternateItemGroup id.