org.omnifaces.utils.stream.RangeIterator Maven / Gradle / Ivy

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package org.omnifaces.utils.stream;

import static org.omnifaces.utils.function.Predicates.isLessThan;
import static org.omnifaces.utils.function.Predicates.isLessThanOrEqual;

import java.util.Comparator;
import java.util.Iterator;
import java.util.NoSuchElementException;
import java.util.function.Function;
import java.util.function.Predicate;

class RangeIterator implements Iterator {

	private T next;
	private final Predicate hasNext;
	private final Function incrementer;

	RangeIterator(T start, T end, boolean rangeClosed, Comparator comparator, Function incrementer) {
		this.next = start;
		this.hasNext = rangeClosed ? isLessThanOrEqual(end, comparator) : isLessThan(end, comparator);
		this.incrementer = incrementer;
	}

	@Override
	public boolean hasNext() {
		return hasNext.test(next);
	}

	@Override
	public T next() {
		if (!hasNext()) {
			throw new NoSuchElementException();
		}

		T current = next;

		next = incrementer.apply(next);

		return current;
	}
}