MessageFormat setFormats() method in Java with Example

Last Updated : 16 Aug, 2021

The setFormats() method of java.text.MessageFormat class is used to set the array of new format element in the pattern of message format object by overriding the old pattern.

Syntax:

public void setFormats(Format[] newFormats)

Parameter: This method takes array of format element as a parameter for overriding the old pattern of message format object.
Return Value: This method has nothing to return.
Exception: This method throws NullPointerException if array of new format element is null.

Below are the examples to illustrate the setFormats() method:

Example 1:

Java

// Java program to demonstrate
// setFormats() method

import java.text.*;
import java.util.*;
import java.io.*;

public class GFG {
    public static void main(String[] argv)
    {
        try {
            // creating and initializing  MessageFormat
            MessageFormat mf
                = new MessageFormat("{0, date, #}, {0, number, #.##}, {0, time}");

            // display the current message format object
            displayFormat(mf);

            // creating and initializing new Format object array
            Format[] format = { new SimpleDateFormat("YYYY-'W'ww-u"),
                                new DecimalFormat("0.##") };

            // setting the new array of formats
            // in the pattern of MessageFormat object
            // using setFormats() method
            mf.setFormats(format);

            // display the Override MessageFormat object
            System.out.println();
            displayFormat(mf);
        }
        catch (NullPointerException e) {
            System.out.println("format array is null");
            System.out.println("Exception thrown : " + e);
        }
    }

    // Defining displayFormat method
    public static void displayFormat(MessageFormat mf)
    {

        // display the result
        System.out.println("pattern : "
                           + mf.toPattern());

        // getting all format
        // used in MessageFormat Object
        // using getFormats() method
        Format[] formats = mf.getFormats();

        // display the result
        System.out.println("Required Formats are : ");
        for (int i = 0; i < formats.length; i++)
            System.out.println(formats[i]);
    }
}

Output:

pattern : {0, date, #}, {0, number, #0.##}, {0, time}
Required Formats are : 
java.text.SimpleDateFormat@403
java.text.DecimalFormat@674fc
java.text.SimpleDateFormat@8400729

pattern : {0, date, YYYY-'W'ww-u}, {0, number, #0.##}, {0, time}
Required Formats are : 
java.text.SimpleDateFormat@d21287d2
java.text.DecimalFormat@674dc
java.text.SimpleDateFormat@8400729

Example 2:

Java

// Java program to demonstrate
// setFormats() method

import java.text.*;
import java.util.*;
import java.io.*;

public class GFG {
    public static void main(String[] argv)
    {
        try {
            // creating and initializing  MessageFormat
            MessageFormat mf
                = new MessageFormat("{0, date, #}, {0, number, #.##}, {0, time}");

            // display the current message format object
            displayFormat(mf);

            // creating and initializing new Format object array
            Format[] format = { new SimpleDateFormat("YYYY-'W'ww-u"),
                                new DecimalFormat("0.##") };

            // setting the new array of formats
            // in the pattern of MessageFormat object
            // using setFormats() method
            mf.setFormats(null);

            // display the Override MessageFormat object
            System.out.println();
            displayFormat(mf);
        }
        catch (NullPointerException e) {
            System.out.println("\nformat array is null");
            System.out.println("Exception thrown : " + e);
        }
    }

    // Defining displayFormat method
    public static void displayFormat(MessageFormat mf)
    {

        // display the result
        System.out.println("pattern : "
                           + mf.toPattern());

        // getting all format
        // used in MessageFormat Object
        // using getFormats() method
        Format[] formats = mf.getFormats();

        // display the result
        System.out.println("Required Formats are : ");
        for (int i = 0; i < formats.length; i++)
            System.out.println(formats[i]);
    }
}

Output:

pattern : {0, date, #}, {0, number, #0.##}, {0, time}
Required Formats are : 
java.text.SimpleDateFormat@403
java.text.DecimalFormat@674fc
java.text.SimpleDateFormat@8400729

format array is null
Exception thrown : java.lang.NullPointerException

Reference: https://docs.oracle.com/javase/9/docs/api/java/text/MessageFormat.html#setFormats-java.text.Format:A-