The java.util.prefs
package contains classes and interfaces for managing persistant
user and
system-wide preferences for Java applications and classes. Most
applications will use only the Preferences class
itself. Some will also use the event objects and listener interfaces
defined by this package, and some may need to explicitly catch the
types of exceptions defined by this package. Application programmers
never need to use the PreferencesFactory interface
or the AbstractPreferences class, which are
intended for Preferences implementors only. To use the Preferences class, first use a static
method to obtain an appropriate Preferences object
or objects, and then use a get( ) method to query
a preference value or a put( ) method to set a
preference value. The code below shows a typical usage. See the
Preferences class for details. import java.util.prefs.Preferences;
public class TextEditor {
// some constants that define default values for preferences
public static final int WIDTH_DEFAULT = 80;
public static final String DICTIONARY_DEFAULT = ";
// Fields to be initialized from preference values
public int width; // Screen width in columns
public String dictionary; // Dictionary name for spell-checking
public void initPrefs( ) {
// Get Preferences objects for user and system preferences for this package
Preferences userprefs = Preferences.userNodeForPackage(TextEditor.class);
Preferences sysprefs = Preferences.systemNodeForPackage(TextEditor.class);
// Look up preference values. Note that we always pass a default value
width = userprefs.getInt("width", WIDTH_DEFAULT);
// Look up a user preference using a system preference as the default
dictionary = userprefs.get("dictionary",
sysprefs.get("dictionary",
DICTIONARY_DEFAULT));
}
}
Interfaces
public interface NodeChangeListener extends java.util.EventListener;
public interface PreferenceChangeListener extends java.util.EventListener;
public interface PreferencesFactory ; Events
public class NodeChangeEvent extends java.util.EventObject;
public class PreferenceChangeEvent extends java.util.EventObject; Other Classes
public abstract class Preferences ;
public abstract class AbstractPreferences extends Preferences; Exceptions
public class BackingStoreException extends Exception;
public class InvalidPreferencesFormatException extends Exception; |