CODEWITHSUNDEEP
javaseleniumxpathlambdajava-8
Vinh
Vinh

Reputation: 31

Using a lambda for mechanism to find element in selenium

I have a snip code using lambda, but got error

"target type of a lambda conversion must be an interface".

Anyone can help? My code is as follows:

private By optStarGrade = (strStar) -> { By.xpath("//input[@id='" + strStar + "'"); };

Upvotes: 3

Views: 1137

Answers (2)

Naman
Naman

Reputation: 32018

Method

To simplify what you probably are trying out and to correlate it better you can start off with your current code represented as a method. This method is trying to find a optStarGrade of type By for a given strStar which is a subpart of your XPath, which would look something like:

public static By optStarGradeFunction(String strStar) {
    return By.xpath("//input[@id='" + strStar + "'");
}

and then you can create the mechanism By as:

By optStarGrade = findByXPath("XPath");

Anonymous class

A similar representation of this method(a.k.a function) would be :

Function<String, By> optStarGradeFunction = new Function<String, By>() {
    @Override
    public By apply(String strStar) {
        return By.xpath("//input[@id='" + strStar + "'");
    }
};

and then accessible as

By optStarGrade = optStarGradeFunction.apply("XPath"); // calls the above 'apply' method

Lambda

But then, the Function could be represented using lambda as simple as :

Function<String, By> optStarGradeFunction = strStar -> By.xpath("//input[@id='" + strStar + "'");

Upvotes: 1

Ousmane D.
Ousmane D.

Reputation: 56463

By is a class, so it cannot be used as a target type for a lambda expression.

Only interfaces with a SAM (Single Abstract Method) can be used as target types for lambda expressions.

So, if you really wanted to use a lambda, then use a Consumer<String>:

private Consumer<String> optStarGrade = (strStar) -> {By.xpath("//input[@id='" + strStar + "'");};

if you don't want to ignore the returned value from By.xpath then use Function<String, By>

private Function<String, By> optStarGrade = (strStar) -> By.xpath("//input[@id='" + strStar + "'");

See the Function and Consumer functional interfaces for more information.

Upvotes: 2

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