Kotlin Java streams - map Selenium WebElement(s) to List-CodePudding

I'm struggling a bit with a pretty simple case of mapping a list of Selenium WebElements to a List of classes using Java Streams.

The element:

val elements: List<WebElement> = element.findElements(By.cssSelector("[data-e2e-selector=expense]"))

(Currently, there are only two elements in the list.)

I'm currently mapping the WebElement list to a MutableList of classes the "classic way":

val expenseElements: MutableList<ExpenseElement> = ArrayList()

for (element in elements) {
    expenseElements  = ExpenseElement(element)
}

Which is working fine. But I feel I should learn to use Stram() to do this more "elegantly". Or, at least, because I want to :-)

But my feeble attempt at using Stream()

val expenseElements = elements.stream().map { UtgiftElement(element) }.collect(Collectors.toList())

results in only the first element being included. So the first elements takes up both places in the the list.

The first method:

expenseElements[0].expense() = "Entry 1"
expenseElements[1].expense() = "Entry 2"

The non-working Stream() method:

expenseElements[0].expense() = "Entry 1"
expenseElements[1].expense() = "Entry 1"

This is basic I know, but I've tried replicating code that does the same in Java. I have to start somewhere.

CodePudding user response：

There's a mistake in your mapping lambda. You do:

map { UtgiftElement(element) }

But that is not correct. The map function provides you with a single input, named it by default. Your lambda should either by map { UtgiftElement(it) } or map { element -> UtgiftElement(element) }.

I do not know where your element variable comes from, but I think it is not one of the elements in the stream.