Class ArabicTextHandler


  • public final class ArabicTextHandler
    extends java.lang.Object
    Handles the processing of arabic text. In particular it determines the form each arabic char should take. It also contains methods for substituting plain arabic glyphs with their shaped forms. This is needed when the arabic text is rendered using an AWT font.
    Version:
    $Id: ArabicTextHandler.java 1808977 2017-09-20 09:06:07Z ssteiner $
    • Constructor Summary

      Constructors 
      Modifier Constructor Description
      private ArabicTextHandler()
      private ctor prevents unnecessary instantiation of this class.
    • Method Summary

      All Methods Static Methods Concrete Methods 
      Modifier and Type Method Description
      static boolean arabicChar​(char c)
      Returns true if the char is a standard arabic char.
      private static boolean arabicCharShaped​(char c)
      Returns true if character is shaped.
      private static boolean arabicCharShapesDuel​(char c)
      Returns true if character has duel shaping.
      private static boolean arabicCharShapesLeft​(char c)
      Returns true if character shapes to the left.
      private static boolean arabicCharShapesRight​(char c)
      Returns true if the character shapes to the right.
      static boolean arabicCharTransparent​(char c)
      Returns true if the char is transparent.
      static java.text.AttributedString assignArabicForms​(java.text.AttributedString as)
      If the AttributedString contains any arabic chars, assigns an arabic form attribute, i.e. initial|medial|terminal|isolated, to each arabic char.
      static boolean charStartsLigature​(char c)
      Returns true if a ligature exists that starts with the specified character.
      static boolean containsArabic​(java.text.AttributedCharacterIterator aci)
      Returns true if the ACI contains any arabic characters.
      static boolean containsArabic​(java.text.AttributedString as)
      Returns true if the string contains any arabic characters.
      static java.lang.String createSubstituteString​(java.text.AttributedCharacterIterator aci)
      Where possible substitues plain arabic glyphs with their shaped forms.
      static int getNumChars​(char c)
      Returns the number of characters the glyph for the specified character represents.
      static int getSubstituteChar​(char ch1, char ch2, int form)
      Will try and find a substitute character of the specified form.
      static int getSubstituteChar​(char ch, int form)  
      static boolean hasSubstitute​(char ch1, char ch2)  
      static boolean isLigature​(char c)
      Returns true if the glyph for the specified character respresents a ligature.
      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
    • Field Detail

      • ARABIC_FORM

        private static final java.text.AttributedCharacterIterator.Attribute ARABIC_FORM
      • ARABIC_NONE

        private static final java.lang.Integer ARABIC_NONE
      • ARABIC_ISOLATED

        private static final java.lang.Integer ARABIC_ISOLATED
      • ARABIC_TERMINAL

        private static final java.lang.Integer ARABIC_TERMINAL
      • ARABIC_INITIAL

        private static final java.lang.Integer ARABIC_INITIAL
      • ARABIC_MEDIAL

        private static final java.lang.Integer ARABIC_MEDIAL
      • singleCharFirst

        static int singleCharFirst
      • singleCharLast

        static int singleCharLast
      • singleCharRemappings

        static int[][] singleCharRemappings
      • doubleCharFirst

        static int doubleCharFirst
      • doubleCharLast

        static int doubleCharLast
      • doubleCharRemappings

        static int[][][] doubleCharRemappings
    • Constructor Detail

      • ArabicTextHandler

        private ArabicTextHandler()
        private ctor prevents unnecessary instantiation of this class.
    • Method Detail

      • assignArabicForms

        public static java.text.AttributedString assignArabicForms​(java.text.AttributedString as)
        If the AttributedString contains any arabic chars, assigns an arabic form attribute, i.e. initial|medial|terminal|isolated, to each arabic char.
        Parameters:
        as - The string to attach the arabic form attributes to.
        Returns:
        An attributed string with arabic form attributes.
      • arabicChar

        public static boolean arabicChar​(char c)
        Returns true if the char is a standard arabic char. (ie. within the range U+0600 - U+6FF)
        Parameters:
        c - The character to test.
        Returns:
        True if the char is arabic, false otherwise.
      • containsArabic

        public static boolean containsArabic​(java.text.AttributedString as)
        Returns true if the string contains any arabic characters.
        Parameters:
        as - The string to test.
        Returns:
        True if at least one char is arabic, false otherwise.
      • containsArabic

        public static boolean containsArabic​(java.text.AttributedCharacterIterator aci)
        Returns true if the ACI contains any arabic characters.
        Parameters:
        aci - The AttributedCharacterIterator to test.
        Returns:
        True if at least one char is arabic, false otherwise.
      • arabicCharTransparent

        public static boolean arabicCharTransparent​(char c)
        Returns true if the char is transparent.
        Parameters:
        c - The character to test.
        Returns:
        True if the character is transparent, false otherwise.
      • arabicCharShapesRight

        private static boolean arabicCharShapesRight​(char c)
        Returns true if the character shapes to the right. Note that duel shaping characters also shape to the right and so will return true.
        Parameters:
        c - The character to test.
        Returns:
        True if the character shapes to the right, false otherwise.
      • arabicCharShapesDuel

        private static boolean arabicCharShapesDuel​(char c)
        Returns true if character has duel shaping.
        Parameters:
        c - The character to test.
        Returns:
        True if the character is duel shaping, false otherwise.
      • arabicCharShapesLeft

        private static boolean arabicCharShapesLeft​(char c)
        Returns true if character shapes to the left. Note that duel shaping characters also shape to the left and so will return true.
        Parameters:
        c - The character to test.
        Returns:
        True if the character shapes to the left, false otherwise.
      • arabicCharShaped

        private static boolean arabicCharShaped​(char c)
        Returns true if character is shaped.
        Parameters:
        c - The character to test.
        Returns:
        True if the character is shaped, false otherwise.
      • hasSubstitute

        public static boolean hasSubstitute​(char ch1,
                                            char ch2)
      • getSubstituteChar

        public static int getSubstituteChar​(char ch1,
                                            char ch2,
                                            int form)
        Will try and find a substitute character of the specified form.
        Parameters:
        ch1 - The first character of two to replace.
        ch2 - The second character of two to replace.
        form - Indicates the required arabic form. (isolated = 1, final = 2, initial = 3, medial = 4)
        Returns:
        The unicode value of the substutute char, or -1 if no substitute exists.
      • getSubstituteChar

        public static int getSubstituteChar​(char ch,
                                            int form)
      • createSubstituteString

        public static java.lang.String createSubstituteString​(java.text.AttributedCharacterIterator aci)
        Where possible substitues plain arabic glyphs with their shaped forms. This is needed when the arabic text is rendered using an AWT font. Simple arabic ligatures will also be recognised and replaced by a single character so the length of the resulting string may be shorter than the number of characters in the aci.
        Parameters:
        aci - Contains the text to process. Arabic form attributes should already be assigned to each arabic character.
        Returns:
        A String containing the shaped versions of the arabic characters
      • charStartsLigature

        public static boolean charStartsLigature​(char c)
        Returns true if a ligature exists that starts with the specified character.
        Parameters:
        c - The character to test.
        Returns:
        True if there is a ligature that starts with c, false otherwise.
      • getNumChars

        public static int getNumChars​(char c)
        Returns the number of characters the glyph for the specified character represents. If the glyph represents a ligature this will be 2, otherwise 1.
        Parameters:
        c - The character to test.
        Returns:
        The number of characters the glyph for c represents.
      • isLigature

        public static boolean isLigature​(char c)
        Returns true if the glyph for the specified character respresents a ligature.
        Parameters:
        c - The character to test.
        Returns:
        True if c is a ligature, false otherwise.