Data Structures - Java 6 - page 233

Price: $2650.0

Title: Cerebus
Issue: 1A
Condition: good
Price: $22.5

8

The ComicBooks application is implemented as two classes: an application class called
ComicBooks and a helper class called Comic .

In the application, the hash table is created in lines 9-22.

First, the hash table is created in line 10.

Next, a float called price1 is created with the value 3.00 . This value is added to the
hash table and associated with the key “mint” . (Remember that hash tables, like other
data structures, can only hold objects—the float value is automatically converted to a
Float object through autoboxing.)

The process is repeated for each of the other comic book conditions from “near mint” to
“poor.”

After the hash table is set up, an array of Comic objects called comix is created to hold
each comic book currently for sale.

The Comic constructor is called with four arguments: the topic's title, issue number, con-
dition, and base price. The first three are strings, and the last is a float .

After a Comic has been created, its setPrice( float ) method is called to set the topic's
price based on its condition. Here's an example, line 27:

comix[0].setPrice( (Float)quality.get(comix[0].condition) );

The hash table's get( String ) method is called with the condition of the topic, a String
that is one of the keys in the table. An Object is returned that represents the value asso-
ciated with that key. (In line 27, because comix[0].condition is equal to “very fine,”
get() returns the floating-point value 3.00F .)

Because get() returns an Object , it must be cast as a Float . The Float argument is
unboxed as a float value automatically through unboxing.

This process is repeated for two more topics.

In lines 33-38, information about each comic book in the comix array is displayed.