The purpose of the |descriptor| is to describe the format of all otherthat may be included in a release. A Descriptor held within the |Descriptor| describes the referencedComponentIdfield and the additional fields for theit describes. Each field is described using ain the metadata. The type of each field is also described in the same way.

Patterns allow a number of different types ofto be defined, each of which will conform to the specified pattern, having the sameformat. The file format of eachpattern is described by a Descriptor Template. This Descriptor Template describes the format and number of additional fields held against members ofconforming to the pattern, and provides an envelope within which those additional fields may be further refined for eachconforming to the pattern. The Descriptor Template for each pattern is provided in the section describing that pattern.

Each definedthat conforms to a pattern will have its own Descriptor, that describes its own specific properties, and althoughfield types must still conform to the Descriptor Template for the pattern, each field type may be further constrained using data sub-types specified in the metadata. This provides some level ofto thethat may be applied to aconforming to a particular pattern.

Figure 3. Graphical view of Relationships between patterns, reference sets, Descriptor Templates and Descriptors

Patterns and Use Cases

The next table summarizes the use cases for(one per row) that are described in the following sections, and shows whichpatterns are used in each case:

Note: The letters shown after each pattern indicate the type and number of additional fields held against each member of aconforming to that pattern, where 'C' is short for, 'S' is short for String (data type) and 'I' is short for Integer .

Example:conforming to the |type| (C) pattern will have one additional field held against each member, a component reference;conforming to the |Simple type| pattern will have no additional fields held against each member.