Programming Languages Saturday, 23 February 2019 Mr C. Coetzee Programming Languages 4.3.10 4.3.11

4.3.10 Describe the characteristics and applications of a collection.

What is a collection? A collection is an object that groups multiple elements into a single unit. Collections are used to store, retrieve, manipulate, and communicate aggregate data. Typically, they represent data items that form a natural group: poker hand (a collection of cards) a mail folder (a collection of letters) telephone directory (a mapping of names to phone numbers).

Collection Frameworks A collections framework is a unified architecture for representing and manipulating collections. All collections frameworks contain the following: Interfaces: abstract data types that represent collections Implementations: concrete implementations of the collection interfaces Algorithms: These are the methods that perform useful computations, such as searching and sorting, on objects that implement collection interfaces. The algorithms are said to be polymorphic: that is, the same method can be used on many different implementations of the appropriate collection interface

Benefits: Java Collections Framework Reduces programming effort Increases program speed and quality Allows interoperability among unrelated APIs Reduces effort to learn and to use new APIs Reduces effort to design new APIs Fosters software reuse API = a set of functions and procedures that allow the creation of applications which access the features or data of an operating system, application, or other service.

4.3.11 Construct algorithms using the access methods of a collection