Java - Character offsetByCodePoints() Method

Description

The Java Character offsetByCodePoints() method is used to retrieve the index within the given char subarray that is offset from the given index by a code point offset.

The subarray is specified in the char array by counting the characters from a certain starting index.

Unpaired surrogates within the text range are to be considered as a one code point each.

This method occurs in two polymorphic forms with same return type but different parameters.

Syntax

Following is the syntax for Java Character offsetByCodePoints() method

public static int offsetByCodePoints(char[] a, int start, int count, int index, int codePointOffset)

(or)

public static int offsetByCodePoints(CharSequence seq, int index, int codePointOffset)

Parameters

a − the char array
start − the index of the first char of the subarray
count − the length of the subarray in chars
index − the index to be offset
seq − the char sequence
codePointOffset − the offset in code points

Return Value

This method returns the index within the subarray

Getting Offset By Code Point Example

The following example shows the usage of Java Character offsetByCodePoints(char[] a, int start, int count, int index, int codePointOffset) method. We've created a char array and initialized with char values. Using offsetByCodePoints() method, we've retrieved the offset and result is printed.

package com.tutorialspoint;

public class CharacterDemo {
   public static void main(String[] args) {

      // create a char array c and assign values
      char[] c = new char[] { 'a', 'b', 'c', 'd', 'e', 'f' };

      // craete 2 int primitives start, count and assign values
      int start = 1;
      int count = 5;

      // create an int primitive res
      int res;

      // assign result of offsetByCodePoints on subarray of c to res
      res = Character.offsetByCodePoints(c, start, count, 2, 4);
      String str = "The index within the subarray of c is " + res;

      // print res value
      System.out.println( str );
   }
}

Output

Let us compile and run the above program, this will produce the following result −

The index within the subarray of c is 6

Getting Offset By Code Point Example

The following example shows the usage of Java Character offsetByCodePoints(CharSequence seq, int index, int codePointOffset). We've created a CharSequence variable and initialized with a String. Using offsetByCodePoints() method, we've retrieved the offset and result is printed.

package com.tutorialspoint;

public class CharacterDemo {
   public static void main(String[] args) {

      // create a CharSequence seq and assign value
      CharSequence seq = "Hello World";

      // create an int primitive res
      int res;

      // assign result of offsetByCodePoints on seq to res
      res = Character.offsetByCodePoints(seq, 3, 8);
      String str = "The index within the char sequence seq is " + res;

      // print res value
      System.out.println( str );
   }
}

Output

Let us compile and run the above program, this will produce the following result −

The index within the char sequence seq is 11

Getting Offset By Code Point from an char Arrays of Digits Example

package com.tutorialspoint;

public class CharacterDemo {
   public static void main(String[] args) {
      char[] c = new char[] { '0', '1', '2', '3', '4', '5' };
      int start = 1;
      int count = 3;
      int result = Character.offsetByCodePoints(c, start, count, 1, 2);
      System.out.println("The index within the subarray of c is " + result);
   }
}

Output

The output for the program above after compiling and execution is printed as follows −

The index within the subarray of c is 3

Facing IndexOutOfBoundsException at while Getting Offset By Code Point from an char Arrays Example

There are also cases when this method throws exceptions. In this example, we will see a scenario where the method throws an IndexOutOfBoundsException.


public class CharacterDemo {
   public static void main(String[] args) {
      char[] c = new char[] { '0', '5', '2', 'a', 'z', '/' };
      int start = 0;
      int count = 3;
      int result = Character.offsetByCodePoints(c, start, count, 2, 4);
      System.out.println("The index within the subarray of c is " + result);
   }
}

Exception

After compiling and running the program above, the output is obtained as follows −

Exception in thread "main" java.lang.IndexOutOfBoundsException at java.lang.Character.offsetByCodePointsImpl(Character.java:5388)
at java.lang.Character.offsetByCodePoints(Character.java:5372)
	at CharacterDemo.main(CharacterDemo.java:10)

Facing NullPointerException at while Getting Offset By Code Point from an char Arrays Example

Now, let us see another scenario where the method throws a NullPointerException.


public class CharacterDemo {
   public static void main(String[] args) {
      char[] c = new char[2];
      c = null;
      int start = 0;
      int count = 0;
      int result = Character.offsetByCodePoints(c, start, count, 0, 0);
      System.out.println("The index within the subarray of c is " + result);
   }
}

Exception

Compile and run the program above, the output will be displayed as −

Exception in thread "main" java.lang.NullPointerExceptionat java.lang.Character.offsetByCodePoints(Character.java:5368)at CharacterDemo.main(CharacterDemo.java:11)

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