带谓词的硒过滤器

Question

我希望使用和了解谓词和 Lambda 表达式。特别是将它与硒一起使用。

假设您有大量的 WebElements 选择（列表）并且您想要对其应用谓词过滤器以使列表更小。

下面的 1、2、3 是否正确，我需要做出哪些改变？

List<WebElement> webElements = driver.findElements(By.cssSelector(".someClassName")); // returns large list  

// then try and filter down the list
Predicate<WebElement> hasRedClass -> Predicate.getAttribute("class").contains("red-background");

Predicate<WebElement> hasDataToggleAttr -> Predicate.getAttribute("data-toggle").size() > 0;

// without predicate  probably  looks like this
//driver.findElements(By.cssSelector(".someClassName .red-background"));

// 1.  this is what I think it should look like???  
List<WebElement> webElementsWithClass =  webElements.filter(hasRedClass);

// 2.  with hasDataToggleAttr
List<WebElement> webElementsWithDataToggleAttr = webElements.filter(hasDataToggleAttr);


// 3.  with both of them together...
List<WebElement> webElementsWithBothPredicates = webElements.filter(hasRedClass, hasDataToggleAttr);

Answer 1

希望这就是您要找的：

List<WebElement> webElements = driver.findElements(By.cssSelector(".someClassName")); // returns large list

// then try and filter down the list
Predicate<WebElement> hasRedClass = we -> we.getAttribute("class").contains("red-background");

Predicate<WebElement> hasDataToggleAttr = we -> we.getAttribute("data-toggle").length() > 0;

// without predicate  probably  looks like this
//driver.findElements(By.cssSelector(".someClassName .red-background"));
// 1.  this is what I think it should look like???
List<WebElement> webElementsWithClass = webElements.stream()
        .filter(hasRedClass).collect(Collectors.toList());

// 2.  with hasDataToggleAttr
List<WebElement> webElementsWithDataToggleAttr = webElements.stream()
        .filter(hasDataToggleAttr).collect(Collectors.toList());

// 3.  with both of them together...
List<WebElement> webElementsWithBothPredicates = webElements.stream()
        .filter(hasDataToggleAttr.and(hasRedClass)).collect(Collectors.toList());