Writing Data to a Sequential Data File - Java Programming: Comprehensive Concepts and Techniques - page 512

3. Enter the code from Figure 8-21 on page 509.
The TextPad window displays the code for the window listener, which
completes the BillPayer() constructor method (Figure 8-24).

showConfirmDialog()
method

addWindowListener()
method

JOptionPane
attribute

FIGURE 8-24

The System.exit argument usually is one (1) if the program terminates for an
error and zero (0) if the program proceeds to its natural conclusion (i.e., the user
clicks the Close button). If the window is closed successfully, the open data file
also will close.

Writing Data to a Sequential Data File

Table 8-10 summarizes the methods from the Data Stream class that transfer
data to and from data files. Notice that there is no writeString() method. Instead,
Java Strings are read or written using a UTF() method. UTF stands for Unicode
Transformation Format , which is an encoding scheme that assigns a number to
each symbol. The UTF() methods provide a way to read and write formatted
data without concern for the specific data type, although the underlying mecha-
nism still is reading one byte at a time.

Table 8-10 Methods to Read and Write from the Data Stream Class

TYPE OF DATA INPUT METHOD OUTPUT METHOD EXAMPLE

boolean data readBoolean() writeBoolean() true or false, stored as

a 1 or 0

single character data readChar() writeChar() a

integer readInt() writeInt() 7

double readDouble() writeDouble() 3.12E+10

float readFloat() writeFloat() 5.21

9 * 10 18 long readLong() writeLong()

Strings readUTF() writeUTF() Cashman's