Question #2: A Case Study: KWIC System The keyword in context system was formulated as following:

The KWIC index system shall accept an ordered set of lines, where each line is an ordered set of words, and each word is an ordered set of characters. Any line shall be circularly shifted by repeatedly removing the first word and appending it at the end of the line. The KWIC index system shall output a listing of all circular shifts of all lines in ascending alphabetical order. KWIC example has been explored for software architectural design alternatives including shared data, implicit invocation, abstract data type, pipe and filter. In our approach, potentially applicable software architectural designs are selected by applying goal oriented NFR approach. Then a set of design patterns is selected. The traceability from the software architectural design to design patterns is evaluated. With consideration of NFRs, the applicability of the design pattern is analyzed. The KWIC example had been used in the course projects in the University of Texas at Dallas. The class size averaged fifty students, altogether several hundreds of students participated the project in the three years. Students in the class made great efforts to incorporate their knowledge of design patterns into the KWIC project. The analysis on the design patterns is incremental. The following explanations are grouped by the types. The types are classified as creational, structural, and behavioral. The creational design patterns used in KWIC system includes Abstract Factory and Singleton,

Abstract Factory: can be used anywhere that needs to create families of objects. Since data representations and related operations are encapsulated in several objects in Abstract Data Type, so Abstract Factory can be applied to create objects for it.

Singleton: comes in when only one instance of Abstract Factory is needed to be globally accessible without resorting to global variables. So, it can be used whenever Abstract Factory is applied. Since Abstract Factory can be used for Abstract Data Type, so does Singleton

Question to be answered (Regarding Case Study)

You must suggest observer pattens and faade pattern to applied in the context presented in the CASE STUDY and give reasonable justification how and why you are suggesting these patterns to be used in this context 10 (2*5) CLO-3, CLO-4

need answer within an hour please be quick and kindly be specific regarding justifications thanks