4.6 Java4040: purpose of framework implementations and algorithms

Revised: Tue Apr 05 15:35:41 CDT 2016

This page is included in the following Books:

• ITSE 2321 - Object-Oriented Programming (Java)
• Object-Oriented Programming (OOP) with Java

Table of contents

• Preface
  • Viewing tip
    • Listings
• Preview
• Generics
• Introduction
• Discussion and sample code
  • Purpose of implementations
    • Available for immediate use
    • Vector and Hashtable classes
    • Abstract implementations
  • Purpose of algorithms
    • The contains method
    • Different classes, different implementations
  • A sample program
    • Instantiate and populate a TreeSet object
    • Instantiate and populate an ArrayList object
    • Identify a target element
    • Search for the test value in each collection
    • Program output
    • Time required to search the ArrayList collection
    • Time required to search the TreeSet collection
    • Different implementations
    • Polymorphic behavior applies
  • Sorting algorithms
  • Now for a little quiz
    • And the answer is ...
    • Drive home the point
  • Benefits of using the Collections Framework
• Run the program
• Summary
• Miscellaneous

Preface

This module is one of a series of modules designed to teach you about Object-Oriented Programming (OOP) in general and the Java CollectionsFramework in particular.

This module explains how the core collection interfaces in the Java Collections Framework allow collections to be manipulated without regard for how they are implemented. The framework provides nine or more concrete implementations of the interfaces. The framework also provides various algorithms for manipulating the data in the collections.

In addition to studying these modules, I strongly recommend that you study the Collections Trail in Oracle's Java Tutorials . The modules in this collection are intended to supplement and not to replace those tutorials.

Viewing tip

I recommend that you open another copy of this module in a separate browser window and use the following links to easily find and view the listings while you are reading about them.

Listings

• Listing 1 . SpeedTest01.
• Listing 2 . Beginning of the doIt method.
• Listing 3 . Instantiate and populate an ArrayList object.
• Listing 4 . Identify a target element.
• Listing 5 . Search for the test value in each collection.

Preview

At least three things are included in the Java Collections Framework:

• interfaces
• implementations
• algorithms

The previous module discussed the purpose of the interfaces. This module will discuss the purpose of the implementations and the algorithms in the CollectionsFramework.

Generics

The code in this series of modules is written with no thought given to Generics . As a result, if you copy and compile the code, you will probably get warnings about unchecked or unsafe operations .

While you will ultimately need to understand how to use Generics, that is a very complex topic. An understanding of Generics is beyond the scope of thiscourse. Therefore, for purposes of this course, you can simply ignore those warnings.