package com.bmchild.utils;

import java.util.Objects;
import java.util.function.Predicate;

/**
 * Non functional way of chaining predicates together
 * @author brettchild
 *
 * @param <T>
 */
public class PredicateChain<T> {
	private T objectToTest;
	private Predicate<T> predicate;
	
	public PredicateChain(T instanceToTest, Predicate<T> predicate) {
		Objects.requireNonNull(instanceToTest);
		Objects.requireNonNull(predicate);
		this.objectToTest = instanceToTest;
		this.predicate = predicate;
	}
	
	/**
	 * Private constructor to create new chains
	 * @param predicate
	 */
	private PredicateChain(Predicate<T> predicate) {
		Objects.requireNonNull(predicate);
		this.predicate = predicate;
	}
	
	public Predicate<T> toPredicate() {
		return t -> this.test();
	}
	
	public boolean test() {
		return predicate.test(objectToTest);
	}
	
	public PredicateChain<T> and(PredicateChain<?> other) {
		Objects.requireNonNull(other);
		return new PredicateChain<T>(t -> this.test() && other.test());
	}
	
	public PredicateChain<T> or(PredicateChain<?> other) {
		Objects.requireNonNull(other);
		return new PredicateChain<T>(t -> this.test() || other.test());
	}
	
	public PredicateChain<T> negate() {
		return new PredicateChain<T>(this.toPredicate().negate());
	}
	
}