java.awt: public final class: ComponentOrientation

java.awt
public final class: ComponentOrientation [javadoc | source]

java.lang.Object
   java.awt.ComponentOrientation

All Implemented Interfaces:
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.

Field Summary
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. To preserve the behavior of existing applications, isLeftToRight will return true for this value.

Method from java.awt.ComponentOrientation Summary:
getOrientation, getOrientation, isHorizontal, isLeftToRight

Methods from java.lang.Object:
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method from java.awt.ComponentOrientation Detail:
public static ComponentOrientation getOrientation(Locale locale) { // A more flexible implementation would consult a ResourceBundle // to find the appropriate orientation. Until pluggable locales // are introduced however, the flexiblity isn't really needed. // So we choose efficiency instead. String lang = locale.getLanguage(); if( "iw".equals(lang) \|\| "ar".equals(lang) \|\| "fa".equals(lang) \|\| "ur".equals(lang) ) { return RIGHT_TO_LEFT; } else { return LEFT_TO_RIGHT; } } Returns the orientation that is appropriate for the given locale.
public static ComponentOrientation getOrientation(ResourceBundle bdl) { ComponentOrientation result = null; try { result = (ComponentOrientation)bdl.getObject("Orientation"); } catch (Exception e) { } if (result == null) { result = getOrientation(bdl.getLocale()); } if (result == null) { result = getOrientation(Locale.getDefault()); } return result; } 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: Retrieve a ComponentOrientation object from the ResourceBundle using the string "Orientation" as the key. Use the ResourceBundle.getLocale to determine the bundle's locale, then return the orientation for that locale. Return the default locale's orientation.
public boolean isHorizontal() { return (orientation & HORIZ_BIT) != 0; } Are lines horizontal? This will return true for horizontal, left-to-right writing systems such as Roman.
public boolean isLeftToRight() { return (orientation & LTR_BIT) != 0; } 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.

Method from java.awt.ComponentOrientation Detail:

 public static ComponentOrientation getOrientation(Locale locale) {
        // A more flexible implementation would consult a ResourceBundle
        // to find the appropriate orientation.  Until pluggable locales
        // are introduced however, the flexiblity isn't really needed.
        // So we choose efficiency instead.
        String lang = locale.getLanguage();
        if( "iw".equals(lang) || "ar".equals(lang)
            || "fa".equals(lang) || "ur".equals(lang) )
        {
            return RIGHT_TO_LEFT;
        } else {
            return LEFT_TO_RIGHT;
        }
}

Returns the orientation that is appropriate for the given locale.

 public static ComponentOrientation getOrientation(ResourceBundle bdl) {
        ComponentOrientation result = null;
        try {
            result = (ComponentOrientation)bdl.getObject("Orientation");
        }
        catch (Exception e) {
        }
        if (result == null) {
            result = getOrientation(bdl.getLocale());
        }
        if (result == null) {
            result = getOrientation(Locale.getDefault());
        }
        return result;
}

Deprecated! As - of J2SE 1.4, use #getOrientation(java.util.Locale) .

Retrieve a ComponentOrientation object from the ResourceBundle using the string "Orientation" as the key.
Use the ResourceBundle.getLocale to determine the bundle's locale, then return the orientation for that locale.
Return the default locale's orientation.

 public boolean isHorizontal() {
                        
        return (orientation & HORIZ_BIT) != 0;
}

Are lines horizontal? This will return true for horizontal, left-to-right writing systems such as Roman.

 public boolean isLeftToRight() {
        return (orientation & LTR_BIT) != 0;
}