* Swing is built upon the foundation that each {@code JComponent} * subclass has an implementation of a specific {@code ComponentUI} * subclass. The {@code ComponentUI} is often referred to as "the ui", * "component ui", or "look and feel delegate". The {@code ComponentUI} * subclass is responsible for providing the look and feel specific * functionality of the component. For example, {@code JTree} requires * an implementation of the {@code ComponentUI} subclass {@code * TreeUI}. The implementation of the specific {@code * ComponentUI} subclass is provided by the {@code LookAndFeel}. Each * {@code JComponent} subclass identifies the {@code ComponentUI} * subclass it requires by way of the {@code JComponent} method {@code * getUIClassID}. *
* Each {@code LookAndFeel} implementation must provide * an implementation of the appropriate {@code ComponentUI} subclass by * specifying a value for each of Swing's ui class ids in the {@code * UIDefaults} object returned from {@code getDefaults}. For example, * {@code BasicLookAndFeel} uses {@code BasicTreeUI} as the concrete * implementation for {@code TreeUI}. This is accomplished by {@code * BasicLookAndFeel} providing the key-value pair {@code * "TreeUI"-"javax.swing.plaf.basic.BasicTreeUI"}, in the * {@code UIDefaults} returned from {@code getDefaults}. Refer to * {@link UIDefaults#getUI(JComponent)} for defails on how the implementation * of the {@code ComponentUI} subclass is obtained. *
* When a {@code LookAndFeel} is installed the {@code UIManager} does * not check that an entry exists for all ui class ids. As such, * random exceptions will occur if the current look and feel has not * provided a value for a particular ui class id and an instance of * the {@code JComponent} subclass is created. * *
* For primitive values, such as {@code opaque}, the method {@code * installProperty} should be invoked. {@code installProperty} only changes * the correspoding property if the value has not been changed by the * developer. *
* {@code ComponentUI} implementations should use the various install methods * provided by this class as they handle the necessary checking and install * the property using the recommended guidelines. *
*
* JComponent c;
* Font font = c.getFont();
* if (font == null || (font instanceof UIResource)) {
* c.setFont(UIManager.getFont("fontKey"));
* }
*
* If the font is {@code null} or a {@code UIResource}, the
* defaults table is queried with the key {@code fontKey}. All of
* {@code UIDefault's} get methods throw a {@code
* NullPointerException} if passed in {@code null}. As such, unless
* otherwise noted each of the various install methods of {@code
* LookAndFeel} throw a {@code NullPointerException} if the current
* value is {@code null} or a {@code UIResource} and the supplied
* defaults key is {@code null}. In addition, unless otherwise specified
* all of the {@code install} methods throw a {@code NullPointerException} if
* a {@code null} component is passed in.
*
* @author Tom Ball
* @author Hans Muller
*/
public abstract class LookAndFeel
{
/**
* Convenience method for setting a component's foreground
* and background color properties with values from the
* defaults. The properties are only set if the current
* value is either {@code null} or a {@code UIResource}.
*
* @param c component to set the colors on
* @param defaultBgName key for the background
* @param defaultFgName key for the foreground
*
* @see #installColorsAndFont
* @see UIManager#getColor
* @throws NullPointerException as described in
* exceptions
*/
public static void installColors(JComponent c,
String defaultBgName,
String defaultFgName)
{
Color bg = c.getBackground();
if (bg == null || bg instanceof UIResource) {
c.setBackground(UIManager.getColor(defaultBgName));
}
Color fg = c.getForeground();
if (fg == null || fg instanceof UIResource) {
c.setForeground(UIManager.getColor(defaultFgName));
}
}
/**
* Convenience method for setting a component's foreground,
* background and font properties with values from the
* defaults. The properties are only set if the current
* value is either {@code null} or a {@code UIResource}.
*
* @param c component set to the colors and font on
* @param defaultBgName key for the background
* @param defaultFgName key for the foreground
* @param defaultFontName key for the font
* @throws NullPointerException as described in
* exceptions
*
* @see #installColors
* @see UIManager#getColor
* @see UIManager#getFont
*/
public static void installColorsAndFont(JComponent c,
String defaultBgName,
String defaultFgName,
String defaultFontName) {
Font f = c.getFont();
if (f == null || f instanceof UIResource) {
c.setFont(UIManager.getFont(defaultFontName));
}
installColors(c, defaultBgName, defaultFgName);
}
/**
* Convenience method for setting a component's border property with
* a value from the defaults. The border is only set if the border is
* {@code null} or an instance of {@code UIResource}.
*
* @param c component to set the border on
* @param defaultBorderName key specifying the border
* @throws NullPointerException as described in
* exceptions
*/
public static void installBorder(JComponent c, String defaultBorderName) {
Border b = c.getBorder();
if (b == null || b instanceof UIResource) {
c.setBorder(UIManager.getBorder(defaultBorderName));
}
}
/**
* Convenience method for uninstalling a border. If the border of
* the component is a {@code UIResource}, it is set to {@code
* null}.
*
* @param c component to uninstall the border on
* @throws NullPointerException if {@code c} is {@code null}
*/
public static void uninstallBorder(JComponent c) {
if (c.getBorder() instanceof UIResource) {
c.setBorder(null);
}
}
/**
* Convenience method for installing a property with the specified name
* and value on a component if that property has not already been set
* by the developer. This method is intended to be used by
* ui delegate instances that need to specify a default value for a
* property of primitive type (boolean, int, ..), but do not wish
* to override a value set by the client. Since primitive property
* values cannot be wrapped with the {@code UIResource} marker, this method
* uses private state to determine whether the property has been set
* by the client.
*
* @throws IllegalArgumentException if the specified property is not
* one which can be set using this method
* @throws ClassCastException if the property value has not been set
* by the developer and the type does not match the property's type
* @throws NullPointerException if {@code c} is {@code null}, or the
* named property has not been set by the developer and
* {@code propertyValue} is {@code null}
* @param c target component to set the property on
* @param propertyName name of the property to set
* @param propertyValue value of the property
* @since 1.5
*/
public static void installProperty(JComponent c,
String propertyName, Object propertyValue) {
// this is a special case because the JPasswordField's ancestor heirarchy
// includes a class outside of javax.swing, thus we cannot call setUIProperty
// directly.
if (c instanceof JPasswordField) {
if (!((JPasswordField)c).customSetUIProperty(propertyName, propertyValue)) {
c.setUIProperty(propertyName, propertyValue);
}
} else {
c.setUIProperty(propertyName, propertyValue);
}
}
/**
* Convenience method for building an array of {@code
* KeyBindings}. While this method is not deprecated, developers
* should instead use {@code ActionMap} and {@code InputMap} for
* supplying key bindings.
*
* This method returns an array of {@code KeyBindings}, one for each
* alternating {@code key-action} pair in {@code keyBindingList}.
* A {@code key} can either be a {@code String} in the format
* specified by the KeyStroke.getKeyStroke method, or
* a {@code KeyStroke}. The {@code action} part of the pair is a
* {@code String} that corresponds to the name of the {@code
* Action}.
*
* The following example illustrates creating a {@code KeyBinding} array * from six alternating {@code key-action} pairs: *
* JTextComponent.KeyBinding[] multilineBindings = makeKeyBindings( new Object[] {
* "UP", DefaultEditorKit.upAction,
* "DOWN", DefaultEditorKit.downAction,
* "PAGE_UP", DefaultEditorKit.pageUpAction,
* "PAGE_DOWN", DefaultEditorKit.pageDownAction,
* "ENTER", DefaultEditorKit.insertBreakAction,
* "TAB", DefaultEditorKit.insertTabAction
* });
*
* If {@code keyBindingList's} length is odd, the last element is
* ignored.
*
* Supplying a {@code null} value for either the {@code key} or
* {@code action} part of the {@code key-action} pair results in
* creating a {@code KeyBinding} with the corresponding value
* {@code null}. As other parts of Swing's expect {@code non-null} values
* in a {@code KeyBinding}, you should avoid supplying {@code null} as
* either the {@code key} or {@code action} part of the {@code key-action}
* pair.
*
* @param keyBindingList an array of {@code key-action} pairs
* @return an array of {@code KeyBindings}
* @throws NullPointerException if {@code keyBindingList} is {@code null}
* @throws ClassCastException if the {@code key} part of the pair is
* not a {@code KeyStroke} or {@code String}, or the
* {@code action} part of the pair is not a {@code String}
* @see ActionMap
* @see InputMap
* @see KeyStroke#getKeyStroke
*/
public static JTextComponent.KeyBinding[] makeKeyBindings(Object[] keyBindingList)
{
JTextComponent.KeyBinding[] rv = new JTextComponent.KeyBinding[keyBindingList.length / 2];
for(int i = 0; i < keyBindingList.length; i += 2) {
KeyStroke keystroke = (keyBindingList[i] instanceof KeyStroke)
? (KeyStroke)keyBindingList[i]
: KeyStroke.getKeyStroke((String)keyBindingList[i]);
String action = (String)keyBindingList[i+1];
rv[i / 2] = new JTextComponent.KeyBinding(keystroke, action);
}
return rv;
}
/**
* Creates a {@code InputMapUIResource} from keys. This is
* a convenience method for creating a new {@code InputMapUIResource},
* invoking {@code loadKeyBindings(map, keys)}, and returning the
* {@code InputMapUIResource}.
*
* @param keys alternating pairs of {@code keystroke-action key}
* pairs as described in {@link #loadKeyBindings}
* @return newly created and populated {@code InputMapUIResource}
* @see #loadKeyBindings
*
* @since 1.3
*/
public static InputMap makeInputMap(Object[] keys) {
InputMap retMap = new InputMapUIResource();
loadKeyBindings(retMap, keys);
return retMap;
}
/**
* Creates a {@code ComponentInputMapUIResource} from
* keys. This is a convenience method for creating a
* new {@code ComponentInputMapUIResource}, invoking {@code
* loadKeyBindings(map, keys)}, and returning the {@code
* ComponentInputMapUIResource}.
*
* @param c component to create the {@code ComponentInputMapUIResource}
* with
* @param keys alternating pairs of {@code keystroke-action key}
* pairs as described in {@link #loadKeyBindings}
* @return newly created and populated {@code InputMapUIResource}
* @throws IllegalArgumentException if {@code c} is {@code null}
*
* @see #loadKeyBindings
* @see ComponentInputMapUIResource
*
* @since 1.3
*/
public static ComponentInputMap makeComponentInputMap(JComponent c,
Object[] keys) {
ComponentInputMap retMap = new ComponentInputMapUIResource(c);
loadKeyBindings(retMap, keys);
return retMap;
}
/**
* Populates an {@code InputMap} with the specified bindings.
* The bindings are supplied as a list of alternating
* {@code keystroke-action key} pairs. The {@code keystroke} is either
* an instance of {@code KeyStroke}, or a {@code String}
* that identifies the {@code KeyStroke} for the binding. Refer
* to {@code KeyStroke.getKeyStroke(String)} for the specific
* format. The {@code action key} part of the pair is the key
* registered in the {@code InputMap} for the {@code KeyStroke}.
*
* The following illustrates loading an {@code InputMap} with two * {@code key-action} pairs: *
* LookAndFeel.loadKeyBindings(inputMap, new Object[] {
* "control X", "cut",
* "control V", "paste"
* });
*
* * Supplying a {@code null} list of bindings ({@code keys}) does not * change {@code retMap} in any way. *
* Specifying a {@code null} {@code action key} results in * removing the {@code keystroke's} entry from the {@code InputMap}. * A {@code null} {@code keystroke} is ignored. * * @param retMap {@code InputMap} to add the {@code key-action} * pairs to * @param keys bindings to add to {@code retMap} * @throws NullPointerException if {@code keys} is * {@code non-null}, not empty, and {@code retMap} is * {@code null} * * @see KeyStroke#getKeyStroke(String) * @see InputMap * * @since 1.3 */ public static void loadKeyBindings(InputMap retMap, Object[] keys) { if (keys != null) { for (int counter = 0, maxCounter = keys.length; counter < maxCounter; counter++) { Object keyStrokeO = keys[counter++]; KeyStroke ks = (keyStrokeO instanceof KeyStroke) ? (KeyStroke)keyStrokeO : KeyStroke.getKeyStroke((String)keyStrokeO); retMap.put(ks, keys[counter]); } } } /** * Creates and returns a {@code UIDefault.LazyValue} that loads an * image. The returned value is an implementation of {@code * UIDefaults.LazyValue}. When {@code createValue} is invoked on * the returned object, the image is loaded. If the image is {@code * non-null}, it is then wrapped in an {@code Icon} that implements {@code * UIResource}. The image is loaded using {@code * Class.getResourceAsStream(gifFile)}. *
* This method does not check the arguments in any way. It is
* strongly recommended that {@code non-null} values are supplied else
* exceptions may occur when {@code createValue} is invoked on the
* returned object.
*
* @param baseClass {@code Class} used to load the resource
* @param gifFile path to the image to load
* @return a {@code UIDefaults.LazyValue}; when resolved the
* {@code LazyValue} loads the specified image
* @see UIDefaults.LazyValue
* @see Icon
* @see Class#getResourceAsStream(String)
*/
public static Object makeIcon(final Class baseClass, final String gifFile) {
return SwingUtilities2.makeIcon(baseClass, baseClass, gifFile);
}
/**
* Returns the LayoutStyle for this look
* and feel. This never returns {@code null}.
*
* You generally don't use the LayoutStyle from
* the look and feel, instead use the LayoutStyle
* method getInstance.
*
* @see LayoutStyle#getInstance
* @return the LayoutStyle for this look and feel
* @since 1.6
*/
public LayoutStyle getLayoutStyle() {
return DefaultLayoutStyle.getInstance();
}
/**
* Invoked when the user attempts an invalid operation,
* such as pasting into an uneditable JTextField
* that has focus. The default implementation beeps. Subclasses
* that wish different behavior should override this and provide
* the additional feedback.
*
* @param component the Component the error occurred in,
* may be null
* indicating the error condition is not directly
* associated with a Component
* @since 1.4
*/
public void provideErrorFeedback(Component component) {
Toolkit toolkit = null;
if (component != null) {
toolkit = component.getToolkit();
} else {
toolkit = Toolkit.getDefaultToolkit();
}
toolkit.beep();
} // provideErrorFeedback()
/**
* Returns the value of the specified system desktop property by
* invoking Toolkit.getDefaultToolkit().getDesktopProperty().
* If the value of the specified property is {@code null},
* {@code fallbackValue} is returned.
*
* @param systemPropertyName the name of the system desktop property being queried
* @param fallbackValue the object to be returned as the value if the system value is null
* @return the current value of the desktop property
*
* @see java.awt.Toolkit#getDesktopProperty
*
* @since 1.4
*/
public static Object getDesktopPropertyValue(String systemPropertyName, Object fallbackValue) {
Object value = Toolkit.getDefaultToolkit().getDesktopProperty(systemPropertyName);
if (value == null) {
return fallbackValue;
} else if (value instanceof Color) {
return new ColorUIResource((Color)value);
} else if (value instanceof Font) {
return new FontUIResource((Font)value);
}
return value;
}
/**
* Returns an Icon with a disabled appearance.
* This method is used to generate a disabled Icon when
* one has not been specified. For example, if you create a
* JButton and only specify an Icon via
* setIcon this method will be called to generate the
* disabled Icon. If {@code null} is passed as
* icon this method returns {@code null}.
*
* Some look and feels might not render the disabled {@code Icon}, in which
* case they will ignore this.
*
* @param component {@code JComponent} that will display the {@code Icon},
* may be {@code null}
* @param icon {@code Icon} to generate the disabled icon from
* @return disabled {@code Icon}, or {@code null} if a suitable
* {@code Icon} can not be generated
* @since 1.5
*/
public Icon getDisabledIcon(JComponent component, Icon icon) {
if (icon instanceof ImageIcon) {
return new ImageIconUIResource(GrayFilter.
createDisabledImage(((ImageIcon)icon).getImage()));
}
return null;
}
/**
* Returns an Icon for use by disabled
* components that are also selected. This method is used to generate an
* Icon for components that are in both the disabled and
* selected states but do not have a specific Icon for this
* state. For example, if you create a JButton and only
* specify an Icon via setIcon this method
* will be called to generate the disabled and selected
* Icon. If {@code null} is passed as icon this
* methods returns {@code null}.
*
* Some look and feels might not render the disabled and selected
* {@code Icon}, in which case they will ignore this.
*
* @param component {@code JComponent} that will display the {@code Icon},
* may be {@code null}
* @param icon {@code Icon} to generate disabled and selected icon from
* @return disabled and selected icon, or {@code null} if a suitable
* {@code Icon} can not be generated.
* @since 1.5
*/
public Icon getDisabledSelectedIcon(JComponent component, Icon icon) {
return getDisabledIcon(component, icon);
}
/**
* Return a short string that identifies this look and feel, e.g.
* "CDE/Motif". This string should be appropriate for a menu item.
* Distinct look and feels should have different names, e.g.
* a subclass of MotifLookAndFeel that changes the way a few components
* are rendered should be called "CDE/Motif My Way"; something
* that would be useful to a user trying to select a L&F from a list
* of names.
*
* @return short identifier for the look and feel
*/
public abstract String getName();
/**
* Return a string that identifies this look and feel. This string
* will be used by applications/services that want to recognize
* well known look and feel implementations. Presently
* the well known names are "Motif", "Windows", "Mac", "Metal". Note
* that a LookAndFeel derived from a well known superclass
* that doesn't make any fundamental changes to the look or feel
* shouldn't override this method.
*
* @return identifier for the look and feel
*/
public abstract String getID();
/**
* Return a one line description of this look and feel implementation,
* e.g. "The CDE/Motif Look and Feel". This string is intended for
* the user, e.g. in the title of a window or in a ToolTip message.
*
* @return short description for the look and feel
*/
public abstract String getDescription();
/**
* Returns {@code true} if the LookAndFeel returned
* RootPaneUI instances support providing {@code Window}
* decorations in a JRootPane.
*
* The default implementation returns {@code false}, subclasses that * support {@code Window} decorations should override this and return * {@code true}. * * @return {@code true} if the {@code RootPaneUI} instances created by * this look and feel support client side decorations * @see JDialog#setDefaultLookAndFeelDecorated * @see JFrame#setDefaultLookAndFeelDecorated * @see JRootPane#setWindowDecorationStyle * @since 1.4 */ public boolean getSupportsWindowDecorations() { return false; } /** * If the underlying platform has a "native" look and feel, and * this is an implementation of it, return {@code true}. For * example, when the underlying platform is Solaris running CDE * a CDE/Motif look and feel implementation would return {@code * true}. * * @return {@code true} if this look and feel represents the underlying * platform look and feel */ public abstract boolean isNativeLookAndFeel(); /** * Return {@code true} if the underlying platform supports and or permits * this look and feel. This method returns {@code false} if the look * and feel depends on special resources or legal agreements that * aren't defined for the current platform. * * * @return {@code true} if this is a supported look and feel * @see UIManager#setLookAndFeel */ public abstract boolean isSupportedLookAndFeel(); /** * Initializes the look and feel. While this method is public, * it should only be invoked by the {@code UIManager} when a * look and feel is installed as the current look and feel. This * method is invoked before the {@code UIManager} invokes * {@code getDefaults}. This method is intended to perform any * initialization for the look and feel. Subclasses * should do any one-time setup they need here, rather than * in a static initializer, because look and feel class objects * may be loaded just to discover that {@code isSupportedLookAndFeel()} * returns {@code false}. * * @see #uninitialize * @see UIManager#setLookAndFeel */ public void initialize() { } /** * Uninitializes the look and feel. While this method is public, * it should only be invoked by the {@code UIManager} when * the look and feel is uninstalled. For example, * {@code UIManager.setLookAndFeel} invokes this when the look and * feel is changed. *
* Subclasses may choose to free up some resources here. * * @see #initialize * @see UIManager#setLookAndFeel */ public void uninitialize() { } /** * Returns the look and feel defaults. While this method is public, * it should only be invoked by the {@code UIManager} when the * look and feel is set as the current look and feel and after * {@code initialize} has been invoked. * * @return the look and feel defaults * @see #initialize * @see #uninitialize * @see UIManager#setLookAndFeel */ public UIDefaults getDefaults() { return null; } /** * Returns a string that displays and identifies this * object's properties. * * @return a String representation of this object */ public String toString() { return "[" + getDescription() + " - " + getClass().getName() + "]"; } }