Event Handling with the Swing Component Set - The Definitive Guide to Java Swing - page 40

AbstractAction Properties
As Table 2-2 shows, the AbstractAction class has three available properties.

Table 2-2. AbstractAction Properties
Property Name

Data Type Access

enabled boolean Read-write bound

keys Object [ ] Read-only

propertyChangeListeners PropertyChangeListener[ ] Read-only

The remainder of the bound properties are placed in the lookup table with putValue
(String key, Object value) . Getting the current keys property setting allows you to find out
which ones can be set en masse, instead of asking for each one individually. Table 2-3 describes
the predefined set of Action constants that can be used as the key. You can also add your own
constants, to look up later when the action happens.

Table 2-3. AbstractAction Lookup Property Keys

Constant Description

Action name, used as button label

NAME

Icon for the Action , used as button label

SMALL_ICON

Short description of the Action ; could be used as tooltip text, but
not by default

SHORT_DESCRIPTION

Long description of the Action ; could be used for accessibility
(see Chapter 22)

LONG_DESCRIPTION

KeyStroke string; can be used as the accelerator for the Action

ACCELERATOR

InputMap key; maps to the Action in the ActionMap of the associ-
ated JComponent

ACTION_COMMAND_KEY

MNEMONIC_KEY Key code; can be used as mnemonic for action

DEFAULT

Unused constant that could be used for your own property

Once a property has been placed in the lookup table, you can get it with public Object
getValue(String key) . It works similarly to the java.util.Hashtable class or java.util.Map
interface, with one distinction: if you try to put a key/value pair into the table with a null value,
the table removes the key, if it's present.

KeyStroke Class
The KeyStroke class and the inputMap and actionMap properties of a specific JComponent provide
a simple replacement for registering KeyListener objects to components and watching for