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package com.github.tadukoo.util.functional.predicate;

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

/**
 * A better version of Java's {@link Predicate} interface that 
 * allows for the predicates to throw whatever {@link Throwable}
 * is specified.
 *
 * @param  The input argument type for the predicate
 * @param  The type of {@link Throwable} thrown by the predicate
 * 
 * @author Logan Ferree (Tadukoo)
 * @version 0.1-Alpha-SNAPSHOT
 */
@FunctionalInterface
public interface ThrowingPredicate{
	
	/**
	 * Takes a single argument and returns a boolean.
	 * 
	 * @param a The argument
	 * @return A boolean
	 * @throws T Determined by the predicate, not required
	 */
	boolean test(A a) throws T;
	
	/**
	 * Creates a ThrowingPredicate that will test the argument with this ThrowingPredicate 
	 * and with the given ThrowingPredicate, returning true only if both results are true.
	 * 
	 * @param other The other ThrowingPredicate to test the argument on
	 * @return The ThrowingPredicate that results from composing this one and the given one
	 */
	default ThrowingPredicate and(ThrowingPredicate other){
		return a -> this.test(a) && other.test(a);
	}
	
	/**
	 * Creates a ThrowingPredicate that will test the argument with this ThrowingPredicate 
	 * and with the given ThrowingPredicate, returning true if either result is true.
	 * 
	 * @param other The other ThrowingPredicate to test the argument on
	 * @return The ThrowingPredicate that results from composing this one and the given one
	 */
	default ThrowingPredicate or(ThrowingPredicate other){
		return a -> this.test(a) || other.test(a);
	}
	
	/**
	 * Creates a ThrowingPredicate that will return the opposite result of this ThrowingPredicate.
	 * 
	 * @return A negated version of this ThrowingPredicate
	 */
	default ThrowingPredicate negate(){
		return a -> !this.test(a);
	}
	
	/**
	 * Creates a ThrowingPredicate that tests if two arguments are equal according 
	 * to Objects.equals(Object, Object).
	 * 
	 * @param  The argument type
	 * @param  The {@link Throwable} being thrown
	 * @param obj The object to test against
	 * @return A ThrowingPredicate that tests if two objects are equal
	 */
	static  ThrowingPredicate isEqual(Object obj){
		return a -> Objects.equals(obj, a);
	}
}