Class ComponentOrientation

java.lang.Object
java.awt.ComponentOrientation
All Implemented Interfaces:
Serializable
public final class ComponentOrientation extends Object implements Serializable
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.
See Also:

  • Field Summary

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

  • Method Summary

    Modifier and Type
    Method
    Description
    static ComponentOrientation
    getOrientation(Locale locale)
    Returns the orientation that is appropriate for the given locale.
    static ComponentOrientation
    getOrientation(ResourceBundle bdl)
    Deprecated.
    As of J2SE 1.4, use getOrientation(java.util.Locale).
    boolean
    isHorizontal()
    Are lines horizontal?
    boolean
    isLeftToRight()
    HorizontalLines: Do items run left-to-right?

    Methods declared in class Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
    Modifier and Type
    Method
    Description
    protected Object
    clone()
    Answers a new instance of the same class as the receiver, whose slots have been filled in with the values in the slots of the receiver.
    boolean
    equals(Object o)
    Compares the argument to the receiver, and answers true if they represent the same object using a class specific comparison.
    protected void
    finalize()
    Deprecated, for removal: This API element is subject to removal in a future version.
    May cause performance issues, deadlocks and hangs.
    final Class<? extends Object>
    getClass()
    Answers the unique instance of java.lang.Class which represents the class of the receiver.
    int
    hashCode()
    Answers an integer hash code for the receiver.
    final void
    notify()
    Causes one thread which is waiting on the receiver to be made ready to run.
    final void
    notifyAll()
    Causes all threads which are waiting on the receiver to be made ready to run.
    String
    toString()
    Answers a string containing a concise, human-readable description of the receiver.
    final void
    wait()
    Causes the thread which sent this message to be made not ready to run pending some change in the receiver (as indicated by notify or notifyAll).
    final void
    wait(long time)
    Causes the thread which sent this message to be made not ready to run either pending some change in the receiver (as indicated by notify or notifyAll) or the expiration of the timeout.
    final void
    wait(long time, int frac)
    Causes the thread which sent this message to be made not ready to run either pending some change in the receiver (as indicated by notify or notifyAll) or the expiration of the timeout.

  • Field Details

    • LEFT_TO_RIGHT

      public static final ComponentOrientation LEFT_TO_RIGHT
      Items run left to right and lines flow top to bottom Examples: English, French.

    • RIGHT_TO_LEFT

      public static final ComponentOrientation RIGHT_TO_LEFT
      Items run right to left and lines flow top to bottom Examples: Arabic, Hebrew.

    • UNKNOWN

      public static final ComponentOrientation UNKNOWN
      Indicates that a component's orientation has not been set. To preserve the behavior of existing applications, isLeftToRight will return true for this value.

  • Method Details

    • isHorizontal

      public boolean isHorizontal()
      Are lines horizontal? This will return true for horizontal, left-to-right writing systems such as Roman.
      Returns:
      true if this orientation has horizontal lines

    • isLeftToRight

      public 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.
      Returns:
      true if this orientation is left-to-right

    • getOrientation

      public static ComponentOrientation getOrientation(Locale locale)
      Returns the orientation that is appropriate for the given locale.
      Parameters:
      locale - the specified locale
      Returns:
      the orientation for the locale

    • getOrientation

      @Deprecated public static ComponentOrientation getOrientation(ResourceBundle bdl)
      Deprecated.
      As of J2SE 1.4, use getOrientation(java.util.Locale).
      Returns the orientation appropriate for the given ResourceBundle's localization. Three approaches are tried, in the following order:
      1. Retrieve a ComponentOrientation object from the ResourceBundle using the string "Orientation" as the key.
      2. Use the ResourceBundle.getLocale to determine the bundle's locale, then return the orientation for that locale.
      3. Return the default locale's orientation.
      Parameters:
      bdl - the bundle to use
      Returns:
      the orientation