OptionalDouble orElseGet() method in Java with examples

The orElseGet(java.util.function.DoubleSupplier) method helps us to get the value in this OptionalDouble object. If a value is not present in this OptionalDouble, then this method returns the result produced by the supplying function, passed as the parameter

Syntax:

public double orElseGet(DoubleSupplier supplier)

Parameters: This method accepts the supplying function that produces a value to be returned.

Return value: This method returns the double value, if present, otherwise the result produced by the supplying function.

Exception: This method throw NullPodoubleerException if no value is present and the supplying function is null.



Below programs illustrate orElseGet(java.util.function.DoubleSupplier) method:

Program 1:

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// Java program to demonstrate
// OptionalDouble.orElseGet(DoubleSupplier) method
  
import java.util.OptionalDouble;
  
public class GFG {
  
    public static void main(String[] args)
    {
  
        // create a OptionalDouble
        OptionalDouble opdouble = OptionalDouble.of(2134);
  
        // get value using orElseGet
        double value = opdouble.orElseGet(() -> getdoubleValue());
  
        // prdouble value
        System.out.println("value: " + value);
    }
  
    public static double getdoubleValue()
    {
        return 3242 + 123;
    }
}

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Output:

value: 2134.0

Program 2:

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// Java program to demonstrate
// OptionalDouble.orElseGet(DoubleSupplier) method
  
import java.util.OptionalDouble;
  
public class GFG {
  
    public static void main(String[] args)
    {
  
        // create a OptionalDouble
        OptionalDouble opdouble = OptionalDouble.empty();
  
        // get value using orElseGet
        double value = opdouble.orElseGet(() -> getdoubleValue());
  
        // prdouble value
        System.out.println("value: " + value);
    }
  
    public static double getdoubleValue()
    {
        return 3242 * 234;
    }
}

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Output:

value: 758628.0

References: https://docs.oracle.com/javase/10/docs/api/java/util/OptionalDouble.html#orElseGet(java.util.function.DoubleSupplier)

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