The PIF Process Interchange Format and Framework

The PIF Process Interchange Format and Framework

Jintae Lee, Gregg Yost and the PIF Working Group[1]
Version 1.0

December 22, 1994

Table of Contents
1. Abstract
2. Introduction
3. History and current status
4. PIF
5. Alphabetic Class Reference
6. Extending PIF
7. Appendix A: PIF Syntax
8. Appendix B: An Example PIF File
9. References

4. PIF

A PIF process description consists of a file of objects, such as ACTIVITY, ACTOR, and RESOURCE objects. Each object in the file has a unique id that other objects can use to refer to it. Each object type (or class) has a particular set of attributes defined for it; each attribute describes some aspect of the object. For example, an ACTOR object has a Skills attribute listing the actor's skills. Object classes fall into a class hierarchy (see Figure 1). Each object class has all of the attributes of all of its superclasses, in addition to its own attributes. For example, all PIF objects have a Name attribute, since the class at the root of the PIF hierarchy (ENTITY) has a Name attribute.

When an attribute of one object has another object as its value, the attribute represents a relationship between the two object classes. For example, an ACTOR's Skill attribute takes SKILL objects as values, so Skill represents a relationship between the ACTOR and SKILL classes. Figure 2 depicts the relationships among the PIF classes.

The PIF hierarchy has grown out of the efforts of the PIF Working Group to share process descriptions among the group members' various tools. We have used the following guidelines in developing this hierarchy:


The current PIF class hierarchy is by no means complete and is still under development. Section 3 describes all of the current PIF classes.

Figure 1: The PIF class hierarchy.


Figure 2: Relationships among PIF classes.

Primitive value types

The value of an attribute in a PIF object is either the unique identifier of another PIF object or a literal value of one of the following primitive PIF value types. Appendix A describes PIF's syntax, including the syntax of these primitive literals.



5. Alphabetic Class Reference