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Vacationing in Java

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This chapter is from the book

Getting Down to Business

At this point in your travels, you might be getting the impression that Java is primarily of use to baseball fans and those who have body parts to show the world. Although those two subject areas are enough to keep most of us entertained for days, the next stop on our trip shows an example of Java getting down to business.

Direct your Web browser to http://www.uralbeacon.co.uk/zoomchart. This example is a financial charting tool presented as a Java program. Historical price and average data is displayed, and users can drag the mouse over an area on a chart to define a new portion of the data to chart, as shown in Figure 3.5.

Unlike other stock analysis programs that require the installation of software on the computers of each employee who needs access, the use of Java enables Ural Beacon to make the program available to anyone with a Web browser—all the employees would have to do is access the company's Web site.

Figure 3.5 A Java program from Ural Beacon that is used to analyze financial data such as stock market prices.

A program such as Ural Beacon's charting applet can be thought of in several different ways. One way is to think of a program as an object—something that exists in the world, takes up space, and has certain things it can do. Java, like the C++ language, uses object-oriented programming, as you will see during Hour 10, "Creating Your First Object." Object-oriented programming (OOP) is a way to design computer programs. A program is thought of as a group of objects. Each object handles a specific task and knows how to speak to other objects. For example, a word processing program could be set up as the following group of objects:

  • A document object, which is the area where you type in text

  • A spell-checking object, which can look over the document object to find any possible spelling errors

  • A printer object, which handles the printing of the document

  • A menu object, a mouse object, and many others

The word processing software is a collection of all the objects necessary to get work done.

OOP is a powerful way to create programs, and it makes the programs you write more useful. Consider word processing software. If the programmer wants to use the spell-checking capabilities of that program with some other software, the spell-checking object is ready for use with the new program. No changes need to be made.

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