ChoiceFormat format() method in Java with Examples

The java.text.ChoiceFormat is a class containing a format() as a function. To obtain the appended string builder of the format value of a specific limit value given as a parameter and text passed as a parameter in this method, utilize the ChoiceFormat class.

Syntax:

public StringBuffer format(double number, StringBuffer toAppendTo, FieldPosition status)

Parameters:

number: which is the particular choiceformat limit object for which it should be appended and must be stored

toAppendTo: which is the updated text that needs to be attached along with the format

status: which determines whether a special status needs to be returned.

Return Value: The StringBuffer object is the result of this method's inserted text and format value.

Exception: If the value of toAppendto is null, this function raises a NullPointerException.

Example 1:

The given Java program demonstrates how to format integers into corresponding string representations using the ChoiceFormat class in accordance with predefined patterns. A ChoiceFormat object is initialized with a pattern that associates the digits 0 through 5 with the months ranging from January to June. The text "Month" is used to initialize a StringBuffer object. The relevant month for the number 6 is then appended to the StringBuffer by the program using the format() function of the ChoiceFormat object. The format() function appends the default representation of the value 6 as it is not present in the defined pattern. The string "Month6" that is generated is printed.

Implementation:

FileName: ChoiceFormatExample1.java

import java.text.*;
import java.util.*;
import java.io.*;
public class ChoiceFormatExample1 
{
     public static void main(String[] argv)
     {
	try 
	{
	       // Initializing and creating the choiceformat
	       ChoiceFormat chofor = new ChoiceFormat( "0#JANUARY | 1#FEBRUARY | 2#MARCH | 3#APRIL | 4#MAY | 5#JUNE");
	       // Initializing and creating the stringbuffer
	       StringBuffer s = new StringBuffer("Month");
	       // getting the required format with appended text
	      // ChoiceFormat Object
	      // using format() method
	     StringBuffer val = chofor.format(6, s, null);
	     System.out.print("The Formatted text with appended value is given by: " + val.toString());
	}
	catch (NullPointerException ex) 
           {
	      System.out.println("\n The String is Null");
	      System.out.println("The Exception thrown is : " + ex);
	}
     }
}

Output:

The Formatted text with appended value is given by: MonthJUNE

Example 2:

The following Java program shows how to handle a NullPointerException when working with null StringBuffer objects and shows how to format integers into equivalent string representations using the ChoiceFormat class. A ChoiceFormat object is initialized by the program with a pattern that maps integers 0 through 5 to January through June. After converting the StringBuffer object to null, it tries to format the number 6 by calling the ChoiceFormat object's format() method. This operation causes a NullPointerException, which is handled by the catch block since the StringBuffer is null. The program shows an illustration of the exception thrown and puts out a message stating that the string is null.

Implementation:

FileName: ChoiceFormatExample2.java

import java.text.*;
import java.util.*;
import java.io.*;
public class ChoiceFormatExample2 
{
	public static void main(String[] argv)
	{
     try 
	     {
		// Initializing and creating the choiceformat
	           ChoiceFormat chofor = new ChoiceFormat( "0#JANUARY | 1#FEBRUARY | 2#MARCH | 3#APRIL | 4#MAY | 5#JUNE");
	       	// Initializing and creating the stringbuffer
		StringBuffer s = null;
            	// getting the required format with appended text
	           // ChoiceFormat Object
	          // using format() method
	          StringBuffer val = chofor.format(6, s, null);
	          System.out.print("The Formatted text with appended value is given by: " + val.toString());
	      }
	      catch (NullPointerException ex) 
                 {
	      	System.out.println("\n The String is Null");
	      	System.out.println("The Exception thrown is : " + ex);
	     }
	}
}

Output:

The String is Null
The Exception thrown is : java.lang.NullPointerException: Cannot invoke "java.lang.StringBuffer.append(String)" because "toAppendTo" is null

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