java - selenium filter with Predicate -

i looking use , learn predicate , lambda expression. in particular using selenium.

imagine have large selection(list) of webelements , want apply predicate filter list smaller .

am on right track 1,2,3 below changes meed make?

list<webelement> webelements = driver.findelements(by.cssselector(".someclassname")); // returns large list    // try , filter down list predicate<webelement> hasredclass -> predicate.getattribute("class").contains("red-background");  predicate<webelement> hasdatatoggleattr -> predicate.getattribute("data-toggle").size() > 0;  // without predicate   looks //driver.findelements(by.cssselector(".someclassname .red-background"));  // 1.  think should like???   list<webelement> webelementswithclass =  webelements.filter(hasredclass);  // 2.  hasdatatoggleattr list<webelement> webelementswithdatatoggleattr = webelements.filter(hasdatatoggleattr);   // 3.  both of them together... list<webelement> webelementswithbothpredicates = webelements.filter(hasredclass, hasdatatoggleattr); 

i hope here looking for:

list<webelement> webelements = driver.findelements(by.cssselector(".someclassname")); // returns large list  // try , filter down list predicate<webelement> hasredclass = -> we.getattribute("class").contains("red-background");  predicate<webelement> hasdatatoggleattr = -> we.getattribute("data-toggle").length() > 0;  // without predicate   looks //driver.findelements(by.cssselector(".someclassname .red-background")); // 1.  think should like??? list<webelement> webelementswithclass = webelements.stream()         .filter(hasredclass).collect(collectors.tolist());  // 2.  hasdatatoggleattr list<webelement> webelementswithdatatoggleattr = webelements.stream()         .filter(hasdatatoggleattr).collect(collectors.tolist());  // 3.  both of them together... list<webelement> webelementswithbothpredicates = webelements.stream()         .filter(hasdatatoggleattr.and(hasredclass)).collect(collectors.tolist());