package org.gcube.data.streams.generators;

import org.gcube.data.streams.Stream;
import org.gcube.data.streams.exceptions.StreamSkipSignal;

/**
 * A {@link Filter} that changes the elements of the input {@link Stream}.
 * 
 * @author Fabio Simeoni
 * 
 * @param <E> the type of input elements
 */
public abstract class Processor<E> extends Filter<E, E> {

	@Override
	public final E yield(E element) {

		process(element);
		return element;
	};

	/**
	 * Processes an element of a {@link Stream}.
	 * 
	 * @param element the input element
	 * @throws StreamSkipSignal if no element <em>should</em> be yielded from the input element (i.e. the element
	 *             should not contribute to the output stream)
	 * @throws RuntimeException ion if no element <em>can</em> be yielded from the input element
	 */
	protected abstract void process(E element);
}