lambda - Java equivalent of Where Clause in C# Linq

Question

I can do this in C# :

int CheetahNumber = 77;
Animal Cheetah = Model.Animals
   .Where(e => e.AnimalNo.Equals(CheetahNumber))
   .FirstOrDefault();

For example in Java I have ArrayList<Animal> Animals

How can I query such an ArrayList? Thanks.

Answer 1

Java 8 introduces the Stream API that allows similar constructs to those in Linq.

Your query for example, could be expressed:

int cheetahNumber = 77;

Animal cheetah = animals.stream()
  .filter((animal) -> animal.getNumber() == cheetahNumber)
  .findFirst()
  .orElse(Animal.DEFAULT);

You'll obviously need to workout if a default exists, which seems odd in this case, but I've shown it because that's what the code in your question does.