Java™ Application Development on Linux - Dator

16.7 Getting Down to Cases: Designing a GUI for BudgetPro35916.7.2.7 JTable: The Workhorse of Data DisplayLook again at our GUI application. In its center you see the table object:This is a JTable. A simple way to create a JTable is by passing in twoarrays to the constructor—first, a two-dimensional array of data objects, andsecond, a one-dimensional array of column names. Notice that we said dataobjects; you need to use Integer objects, not simple int types, and Doublesinstead of doubles. This allows the constructor to take any Object type anddisplay it in the table via the object’s toString() method.While this form of a table is simple to use, it usually isn’t enough for allthe various things you’ll want to do with a table. Let’s look at the “industrialstrength” table initialization. For that, we need to talk about a table model.16.7.2.8 Table ModelIf you’ve ever taken an object-oriented design class, they’ve probably talkedabout the Model/View/Controller design pattern. (If you haven’t taken such aclass, at least read a good book or two on the subject; it will improve your Javaprogramming skills.) A simpler version of this pattern is the View/Model pattern.What it describes is separating the core of the data from the frill of itspresentation—what you want to display versus how you want to display it. TheModel is the underlying data; the View is one particular way to show that data.This View versus Model distinction is used to great effect with JTableand TableModel objects in Swing. What you need to do is create aTableModel, then give that TableModel to the JTable via the JTable’sconstructor. The TableModel will give you all sorts of control over yourdata—how, where, and when to get or update it. The JTable will display itand let you rearrange or resize the columns.Rather than implement a complete TableModel from scratch, Swing givesus a helping hand with its AbstractTableModel class. AbstractTableModelis a partially implemented class which handles most of the grundy details—it