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Phonebook Searching

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With this exercise, you will complete a phonebook look-up applet. The skeleton code creates a GUI that consists of a pull-down list of names, a text field for entry of a phone number to look up, and a command button to activate the look-up operation. It is your job to add the event handling to the applet.

There are three different events that must be handled. When the user changes the name in the pull-down list, the applet should look up the appropriate telephone number in the phonebook. When the user enters a phone number in the text field and presses return or selects the button, the applet should look up the number in the reverse phonebook and change the name in the pull-down list. Finally, the applet should restrict input in the text field to digits and the '-' character. If a look-up operation fails, the applet should simply beep.

The actual telephone book appears below:

Name	Number
Mom	555-1111
Dad	555-2222
Hon	555-3333
Boss	555-4444
Broker	555-5555
Jenny	867-5309

Prerequisites

Counting Mouse Clicks

Skeleton Code

Tasks

1.	To handle selections in the `Choice` object, design a class that implements `ItemListener`. When an item is selected, the applet should look up the name in the `phonebook` hashtable and display the number found in the `entryField` text field.
2.	Register the `ItemListener` with the `Choice` object.
3.	To handle text entry and the look-up operation for the telephone number, design a class that implements `ActionListener`. The phone number from the text field should be looked up in the `reversePhonebook` hashtable and the appropriate name displayed in the `bookChoice` pull-down list.
4.	Instantiate the class (once) that implements `ActionListener` and register it with the `TextField` and `Button` instances.
5.	To restrict input in the `TextField`, design a class that implements `KeyListener` or subclasses `KeyAdapter`. Use this class to reject textfield input that is not a digit or '-'.
6.	To ensure errors can be deleted and retain normal functionality for the Enter and Tab keys, let the Backspace, Delete, Tab, and Enter keys be valid characters for the `keyTyped()` method also.
7.	Register the object that implements `KeyListener` with the `TextField` instance.
8.	Use the `Phone.html` file in the solution to test it.

Where help exists, the task numbers above are linked to the step-by-step help page.

Solution Source

Demonstration

This exercise only runs within browsers that support the Java Runtime Environment 1.1 and appletviewer. If you are using an appropriate browser, try this exercise. The output should look similar to the following:


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Phonebook Searching

Prerequisites

Skeleton Code

Tasks

Solution Source

Demonstration

Next Exercise

Exercises

Short Course