AbstractFilterEventSender.java

package org.sef4j.core.helpers.senders;

import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import java.util.function.Predicate;

import org.sef4j.core.api.EventSender;

public abstract class AbstractFilterEventSender<T> implements EventSender<T> {

	protected EventSender<T> target;
	
	// ------------------------------------------------------------------------

	protected AbstractFilterEventSender(EventSender<T> target) {
		this.target = target;
	}

	// ------------------------------------------------------------------------
	
	@Override
	public void sendEvent(T event) {
		if (acceptEvent(event)) {
			target.sendEvent(event);
		}
	}

	@Override
	public void sendEvents(Collection<T> events) {
		List<T> filteredEvents = new ArrayList<T>(events.size());
		for(T event : events) {
			if (acceptEvent(event)) {
				filteredEvents.add(event);
			}
		}
		if (! filteredEvents.isEmpty()) {
			if (filteredEvents.size() > 1) {
				target.sendEvents(filteredEvents);
			} else {
				target.sendEvent(filteredEvents.get(0));
			}
		}
	}

	protected abstract boolean acceptEvent(T event);
	
	// ------------------------------------------------------------------------

	public static class PredicateFilterEventSender<T> extends AbstractFilterEventSender<T> {
		
		private Predicate<T> predicate;

		public PredicateFilterEventSender(EventSender<T> target, Predicate<T> predicate) {
			super(target);
			this.predicate = predicate;
		}

		@Override
		protected boolean acceptEvent(T event) {
			return predicate.test(event);
		}

		// ------------------------------------------------------------------------
		
		@Override
		public String toString() {
			return "PredicateFilterEventSender [predicate=" + predicate + ", target=" + target + "]";
		}
		
		
	}
	
}