Swing Hacks

Add a Filter History #14

Chapter 2, Lists and Combos

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HACK

H A C K

#14

Add a Filter History

Hack #14

Remember previous searches and research with one click.

Chances are good that if you’ve searched for something once, it’s important

enough that you might well search for it again. In Apple’s Safari browser, a

search widget at the upper right has a little magnifying glass that remembers

your last 10 searches. Click the magnifying glass and a pop up appears with

the previous searches. Select one and it populates the field and does the

search immediately.

Here’s an implementation of the same idea, grafted onto the previous hack.

In other words, this remembers previous filters. It doesn’t remember every

keystroke—why bother remembering the searches “J” and “Jo” when you’re

really just interested in “Joe”—and only adds a search term to the filter

when the user presses return.

In the previous hack, you just needed to have a text field and a

JList. Now a

JButton needs to be attached to the text field, so the two are bundled

together in the inner class

FilterField. This class is responsible for:

• Telling the model to refilter on each keystroke in the

JTextField, as

before.

• Remembering the

JTextField’s contents as a saved search anytime the

Return or Enter key is pressed.

• Catching clicks on the

JButton and popping up a menu with previous

searches.

• Populating the

JTextField with a previous search when one is selected ...