Introduction to Programming

Predicate<T>

This is an interface that represents a Boolean-valued function that has a single method: boolean test(T). Here is an example of a method that creates a Predicate<Integer> function:

Predicate<Integer> createTestSmallerThan(int num){  Predicate<Integer> func = new Predicate<Integer>() {    public boolean test(Integer d) {      return d < num;    }  };  return func;}

We can use it to add some logic to the processing method:

void supplyDecideProcessAndConsume(Supplier<Integer> input,                                   Predicate<Integer> test,                                    Function<Integer, Double> process,                                             Consumer<Double> consume){  int in = input.get();  if(test.test(in)){    consume.accept(process.apply(in));  } else {    System.out.println("Input " + in +                      " does not pass the test and not processed.");  }}

And ...