2.4.4 Folders

Folder objects are hierarchical containers that are used to create a storage hierarchy for the message store. In the PST architecture, a single root Folder object exists at the top of the message store, from which an arbitrarily complex hierarchy of Folder objects descends to provide structured storage for all the Messaging objects.

At the LTP level, a Folder object is a composite entity that is represented using four LTP constructs. Specifically, each Folder object consists of one PC, which contains the properties directly associated with the Folder object, and three TCs for information about the contents, hierarchy and other associated information of the Folder object. Some Folder objects MAY have additional nodes that pertain to Search, which is discussed in section 2.4.8.6.

At the NDB level, the 4 LTP constructs are persisted as 4 separate top-level nodes (that is, 4 different NIDs). For identification purposes, the nidIndex portion for each of the NIDs is the same to indicate that these nodes collectively make up a Folder object. However, each of the 4 NIDs has a different nidType value to differentiate their respective function. The following diagram indicates the relationships among these elements.

Figure 9: Components of a Folder object

The following sections explain the structure and function of each of the 4 composite elements of a Folder object,