checker/tests/optional/Marks3a.java

import java.util.List;
import java.util.Optional;

/**
 * Test case for rule #3: "Prefer alternative APIs over Optional.isPresent() and Optional.get()."
 */
public class Marks3a {

  class Customer {
    int getID() {
      return 42;
    }

    String getName() {
      return "Fozzy Bear";
    }
  }

  String customerNameByID_acceptable(List<Customer> custList, int custID) {
    Optional<Customer> opt = custList.stream().filter(c -> c.getID() == custID).findFirst();

    // :: warning: (prefer.map.and.orelse)
    return opt.isPresent() ? opt.get().getName() : "UNKNOWN";
  }

  String customerNameByID_acceptable2(List<Customer> custList, int custID) {
    Optional<Customer> opt = custList.stream().filter(c -> c.getID() == custID).findFirst();

    // :: warning: (prefer.map.and.orelse)
    return !opt.isPresent() ? "UNKNOWN" : opt.get().getName();
  }

  String customerNameByID_better(List<Customer> custList, int custID) {
    Optional<Customer> opt = custList.stream().filter(c -> c.getID() == custID).findFirst();

    return opt.map(Customer::getName).orElse("UNKNOWN");
  }
}