java.lang.Character class methods | Set 1


java.lang.Character class methods

lang.Character class wraps the value of a primitive data type – char to an object of datatype char and this object contains single field having the data type – char. This class provides no. of methods regarding character manipulations like convert them from lowercase to uppercase. Character class is based on Unicode Standards to provide character information.
Class Declaration:

public final class Character
   extends Object
      implements Serializable, Comparable

Following methods of Character class are discussed here :

  1. charCount() : java.lang.charCount() method uses Unicode point to return the number of char values to represent the argument char values. A Unicode code point is used for character values in the range between U+0000 and U+10FFFF and for 16-bit char values that are code units of the UTF-16 encoding.
    Syntax :

    public static int charCount(int argchar)
    Parameters : 
    argchar : char i.e. it's Unicode point to be counted
    Return : 
    2 if the character is valid i.e. > or = to 0X1000(supplementary character); else 1   
    
  2. charValue() : java.lang.charValue() method returns primitive character value of defined char Object.
    Syntax :

    public char charValue()
    Return : 
    primitive character value of defined char Object.
    
  3. codePointAt() : java.lang.Character.codePointAt(char[ ] array, int position) method returns Unicode Point of the character array present at the argumented position.
    Syntax :

    public static int codePointAt(char[] array, int position)
    Parameters : 
    array    : character array
    position : array index of character whose Unicode Point value you need.  
    Return : 
    Unicode point of the character array present at the given position  
    
  4. Java code explaining use of charCount(), charValue(), codePointat() methods

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    // Java program explaining Character class methods
    // charCount(), charValue(), codePointat()
    import java.lang.Character;
    public class NewClass
    {
        public static void main(String[] args)
        {
            // Use of charCount() method
            int geek = 0x9999,    // < 0x10000
                geek1 = 0x10000,      // = 0x10000
                geek2 = 0x10001;      // > 0x10000
      
            int check = Character.charCount(geek);
            int check1 = Character.charCount(geek1);
            int check2 = Character.charCount(geek2);
      
            if (check ==2)    // Checking for geek
                System.out.println("Valid Character geek");
            else
                System.out.println("Invalid Character geek");
      
            if (check1 ==2)   // Checking for geek1
                System.out.println("Valid Character geek1");
            else
                System.out.println("Invalid Character geek1");
      
            if (check2 ==2)   // Checking for geek2
                System.out.println("Valid Character geek2");
            else
                System.out.println("Invalid Character geek2");
      
            System.out.println("");
      
      
            // Use of charValue() method
            Character m;      // Character object m
      
            m = new Character('g');  // Assigning value g to m;
      
            char gfg;
            gfg = m.charValue();
            System.out.println("Primitive value of gfg : " +gfg);
            System.out.println("");
      
      
            // Use of codePointAt()
            char[] arg = new char[] { 'g', 'e', 'e', 'k', 's' };
            int val, val1, position  = 3;
      
            val = Character.codePointAt(arg, position);
            val1 = Character.codePointAt(arg, 0);
      
            System.out.println( "Unicode code point at " + position
                                                       + " : "+val );
            System.out.println( "Unicode code point at 0 : " + val1);
        }
    }

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    Output:

    Invalid Character geek
    Valid Character geek1
    Valid Character geek2
    
    Primitive value of gfg : g
    
    Unicode code point at 3 : 107
    Unicode code point at 0 : 103
    
  5. codePointBefore() : java.lang.Character.codePointBefore(char[ ] array, int position) method returns Unicode Point of the character array present before the argumented position.
    Syntax :

    public static int codePointBefore(char[] array, int position)
                              or
    public static int codePointBefore(char[] array, int position, int start)
    Parameters : 
    array    : character array
    position : array index of character following the Unicode Point value you need.  
    start : start index of the character array
    Return : 
    Unicode point of the character array present before the given position  
    
  6. codePointCount() : java.lang.Character.codePointCount() method returns no. of Unicode Point of the sub-character array.
    Syntax :

    public static int codePointCount(char[] array, int start, int len)
    Parameters : 
    array  : character array
    start  : starting index of the array
    length : length of the character sub-array   
    Return : 
    no. of Unicode Point of the sub-character array.
    Exception : 
    --> NullPointerException
    --> IndexOutOfBoundsException 
    
  7. compareTo() : java.lang.Character.compareTo(Character argChar) method compares given chararcter with argumented character.
    Syntax :

    public int compareTo(Character argChar)
    Parameters : 
    argChar : character to be compared with  
    Return : 
    = 0 : if both characters are equal 
    > 0 : if given this character is greater
    < 0 : if argumented character is greater
    
  8. Java code explaining use of codePointBefore(), codePointCount(), compareTo() methods

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    // Java program explaining Character class methods
    // codePointBefore(), codePointCount(), compareTo()
    import java.lang.Character;
    public class NewClass
    {
        public static void main(String[] args)
        {
            // Use of codePointBefore()
            char[] arg = new char[] { 'g', 'e', 'e', 'k', 's' };
            int position  = 4;
      
            int val = Character.codePointBefore(arg, position);
            int val1 = Character.codePointBefore(arg, 1);
            int val2 = Character.codePointBefore(arg, 3, 1);
      
            System.out.println( "Unicode code point before " + position +
                                                           " : " + val );
            System.out.println( "Unicode code point before 1 : " + val1 );
            System.out.println( "Unicode code point before 3 to 1 : "
                                                                  + val2);
            System.out.println("");
      
            // Use of codePointCount()
            int count = Character.codePointCount(arg, 1,3 );
      
            System.out.println("No. of Unicode points : " + count);
            System.out.println("");
      
            // Use of compareTo()
            Character g1 = new Character('g');
            Character g2 = new Character('o');
      
            int check = g1.compareTo(g2);
            System.out.println("g1 < g2 : " + check);
            int check1 = g2.compareTo(g1);
            System.out.println("g2 > g1 : " + check1);
            int check2 = g2.compareTo(g2);
            System.out.println("g2 = g2 : " + check2);
        }
    }

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    Output:

    Unicode code point before 4 : 107
    Unicode code point before 1 : 103
    Unicode code point before 3 to 1 : 101
    
    No. of Unicode points : 3
    
    g1  g1 : 8
    g2 = g2 : 0
    
  9. equals() : java.lang.Character.equals() method compares the present char object with the argumented char object.
    Syntax :

    public boolean equals(Object charObj)
    Parameters : 
    charObj : char object to comapre with 
    Return : 
    true if both the objects are equal, else false.
    
  10. getNumericValue() : java.lang.Character.getNumericValue(char arg) method returns int value for the specific Unicode character.
    A – Z value ranges u0041 to u005A
    a -z value ranges u0061 to u007A
    Syntax :

    public static int getNumericValue(char arg)
    Parameters : 
    arg : char value
    Return : 
    int value for the specific Unicode character.
    if Unicode value doesn't exists -1 is returned.
    
  11. getType() : java.lang.Character.getType(char arg) method identifies the general type of character
    A – Z value ranges u0041 to u005A
    a -z value ranges u0061 to u007A
    Syntax :

    public static int getType(char arg)
    Parameters : 
    arg : char value
    Return : 
    int value for the argumented character representing its general type category. 
    
  12. Java code explaining use of equals(), getNumericValue(), getType() methods

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    // Java program explaining Character class methods
    // equals(), getNumericValue(), getType()
    import java.lang.Character;
    public class NewClass
    {
        public static void main(String[] args)
        {
            // Use of equals() method
            Character g1 = new Character('g');
            Character g2 = new Character('O');
      
            boolean check = g1.equals(g2);
            boolean check1 = g1.equals(g1);
            System.out.println("Are g and o equal? : " + check);
            System.out.println("Are g and g equal? : " + check1);
            System.out.println("");
      
            // Use of getNumericValue() method
            int c = Character.getNumericValue(g1);
            int c1 = Character.getNumericValue(g2);
            System.out.println("Int value for g : " + c);
            System.out.println("Int value for A : " + c1);
            System.out.println("");
      
            // Use of getType() method
            Character g3 = new Character('$');
            Character g4 = new Character('6');
      
            int r1 = Character.getType(g1);
            int r2 = Character.getType(g2);
            int r3 = Character.getType(g3);
            int r4 = Character.getType(g4);
      
            System.out.println("Type for lowercase : " + r1);
            System.out.println("Type for uppercase : " + r2);
            System.out.println("Type for currency  : " + r3);
            System.out.println("Type for numeric   : " + r4);
        }
    }

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    Output:

    Are g and o equal? : false
    Are g and g equal? : true
    
    Int value for g : 16
    Int value for A : 24
    
    Type for lowercase : 2
    Type for uppercase : 1
    Type for currency  : 26
    Type for numeric   : 9
    

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