What is StringUtils.getIfBlank in Java?

getIfBlank is a static method of the StringUtils class that works as follows:

The method takes in two arguments. One is the character sequence and the other is a supplier instance.
If the given character sequence is whitespace, empty, or null, then the method returns the value supplied by the supplier.
Otherwise, it returns the given character sequence.

Note: Supplier in Java 8 is a functional interface whose functional method is get(). The interface represents an operation that takes no arguments and returns a result.

StringUtils is defined in the Apache Commons Lang package. Apache Commons Lang can be added to the Maven project by adding the following dependency to the pom.xml file.

<dependency>
            <groupId>org.apache.commons</groupId>
            <artifactId>commons-lang3</artifactId>
            <version>3.12.0</version>
</dependency>

Note: For other versions of the commons-lang package, refer to the Maven Repository.

You can import the StringUtils class as follows:

import org.apache.commons.lang3.StringUtils;

Syntax

public static <T extends CharSequence> T getIfBlank(T str, Supplier<T> defaultSupplier)

Parameters

T str: the string to check
Supplier<T> defaultSupplier: the supplier instance

Return value

The method returns the passed string or the value returned by the supplier.

import org.apache.commons.lang3.StringUtils;
public class Main {
    public static void main(String[] args) {
        String string = "educative";
        String returnValue = StringUtils.getIfBlank(string, () -> "hello");
        System.out.printf("Value Returned for \"%s\" is \"%s\"", string, returnValue);
        System.out.println();
        string = "";
        returnValue = StringUtils.getIfBlank(string, () -> "hello");
        System.out.printf("Value Returned for \"%s\" is \"%s\"", string, returnValue);
        System.out.println();
        string = null;
        returnValue = StringUtils.getIfBlank(string, () -> "hello");
        System.out.printf("Value Returned for \"%s\" is \"%s\"", string, returnValue);
        System.out.println();
        string = "  ";
        returnValue = StringUtils.getIfBlank(string, () -> "hello");
        System.out.printf("Value Returned for \"%s\" is \"%s\"", string, returnValue);
        System.out.println();
    }
}