ComponentOrientation

Class Overview

The ComponentOrientation class encapsulates the language-sensitive orientation that is to be used to order the elements of a component or of text. It is used to reflect the differences in this ordering between Western alphabets, Middle Eastern (such as Hebrew), and Far Eastern (such as Japanese).

Fundamentally, this governs items (such as characters) which are laid out in lines, with the lines then laid out in a block. This also applies to items in a widget: for example, in a check box where the box is positioned relative to the text.

There are four different orientations used in modern languages as in the following table.

 LT          RT          TL          TR
 A B C       C B A       A D G       G D A
 D E F       F E D       B E H       H E B
 G H I       I H G       C F I       I F C
 

(In the header, the two-letter abbreviation represents the item direction in the first letter, and the line direction in the second. For example, LT means "items left-to-right, lines top-to-bottom", TL means "items top-to-bottom, lines left-to-right", and so on.)

The orientations are:

• LT - Western Europe (optional for Japanese, Chinese, Korean)
• RT - Middle East (Arabic, Hebrew)
• TR - Japanese, Chinese, Korean
• TL - Mongolian

Components whose view and controller code depends on orientation should use the isLeftToRight() and isHorizontal() methods to determine their behavior. They should not include switch-like code that keys off of the constants, such as:

 if (orientation == LEFT_TO_RIGHT) {
   ...
 } else if (orientation == RIGHT_TO_LEFT) {
   ...
 } else {
   // Oops
 }
 

This is unsafe, since more constants may be added in the future and since it is not guaranteed that orientation objects will be unique.

Summary

Fields
public static final ComponentOrientation	LEFT_TO_RIGHT	Items run left to right and lines flow top to bottom Examples: English, French.
public static final ComponentOrientation	RIGHT_TO_LEFT	Items run right to left and lines flow top to bottom Examples: Arabic, Hebrew.
public static final ComponentOrientation	UNKNOWN	Indicates that a component's orientation has not been set.

Public Methods
static ComponentOrientation	getOrientation(Locale locale) Returns the orientation that is appropriate for the given locale.
static ComponentOrientation	getOrientation(ResourceBundle bdl) This method is deprecated. As of J2SE 1.4, use getOrientation(java.util.Locale).
boolean	isHorizontal() Are lines horizontal? This will return true for horizontal, left-to-right writing systems such as Roman.
boolean	isLeftToRight() HorizontalLines: Do items run left-to-right? Vertical Lines: Do lines run left-to-right? This will return true for horizontal, left-to-right writing systems such as Roman.

[Expand] Inherited Methods

From class java.lang.Object Object clone() Creates and returns a copy of this object. boolean equals(Object obj) Indicates whether some other object is "equal to" this one. void finalize() Called by the garbage collector on an object when garbage collection determines that there are no more references to the object. final Class<?> getClass() Returns the runtime class of this Object. int hashCode() Returns a hash code value for the object. final void notify() Wakes up a single thread that is waiting on this object's monitor. final void notifyAll() Wakes up all threads that are waiting on this object's monitor. String toString() Returns a string representation of the object. final void wait() Causes the current thread to wait until another thread invokes the notify() method or the notifyAll() method for this object. final void wait(long timeout, int nanos) Causes the current thread to wait until another thread invokes the notify() method or the notifyAll() method for this object, or some other thread interrupts the current thread, or a certain amount of real time has elapsed. final void wait(long timeout) Causes the current thread to wait until either another thread invokes the notify() method or the notifyAll() method for this object, or a specified amount of time has elapsed.