Java – Create verbs on the fly

I

have a String[] for user input, and I want to filter the collection of devices based on whether the hostname of the device contains any user input.

I’m trying to keep up with class https://docs.oracle.com/javase/tutorial/java/javaOO/lambdaexpressions.html do this.

interface PredicateOperation{
    Predicate operation(String[] input);
}

public Predicate getPredicate(String[] input, PredicateOperation op){
    return op.operation(input);
}

private TufinDeviceCollection<TufinDevice> filter(TufinDeviceCollection<TufinDevice> devices) {        

Check if any HostNames of the devices contain any of the items in String[] modelContains

devices = devices.stream()
                    .sequential()
                    .filter(//How do i create this predicate?) we need to create the lamda expression to evaulate if the hostName of device d contains any of the items String[] userInput
                    .collect(Collectors.toCollection(TufinDeviceCollection<TufinDevice>::new));

}

It’s not clear to me how to define PredicateOperation in .filter(

….).

.filter(device -> Arrays.stream(userInput)
                        .anyMatch(input -> device.getHostName().contains(input)))

But you need the String[] userInput method to be accessed from filter.

I’m guessing it’s an attempt to write @FunctionalInterface yourself instead of standard Predicate<T>

interface PredicateOperation {
    Predicate operation(String[] input);
}

Although this is not very practical.

PredicateOperation operation = (String[] input) -> ((Object o) -> true);

Why do I need to return Predicate if I can return results? A small enhanced version would be

interface PredicateOperation {
    boolean operation(String[] input);
}

and

PredicateOperation operation = (String[] input) -> true;

Since Stream#filter, it’s still not particularly useful for the Stream API, expecting a java.util.function.Predicate<T>, not your favorite type.

And, yes, stop using the original Predicate