ecommons.waltable/org.eclipse.statet.ecommons.waltable.core/src/org/eclipse/statet/ecommons/waltable/conflation/EventConflaterChain.java

/*=============================================================================#
 # Copyright (c) 2012, 2021 Original NatTable authors and others.
 # 
 # This program and the accompanying materials are made available under the
 # terms of the Eclipse Public License 2.0 which is available at
 # https://www.eclipse.org/legal/epl-2.0.
 # 
 # SPDX-License-Identifier: EPL-2.0
 # 
 # Contributors:
 #     Original NatTable authors and others - initial API and implementation
 #=============================================================================*/

package org.eclipse.statet.ecommons.waltable.conflation;

import java.util.LinkedList;
import java.util.List;
import java.util.concurrent.ScheduledFuture;

import org.eclipse.statet.ecommons.waltable.layer.event.ILayerEvent;
import org.eclipse.statet.ecommons.waltable.util.Scheduler;


/**
 * A Chain of Conflaters. Every conflater in the chain is given the chance to
 * queue an event. When the chain runs every conflater in the chain can run its
 * own task to handle the events as it sees fit.
 */
public class EventConflaterChain implements IEventConflater {
	
	public static final int DEFAULT_INITIAL_DELAY= 100;
	public static final int DEFAULT_REFRESH_INTERVAL= 50;
	
	private static final Scheduler scheduler= new Scheduler("EventConflaterChain"); //$NON-NLS-1$
	
	
	private final List<IEventConflater> chain= new LinkedList<>();
	private ScheduledFuture<?> future;
	private boolean started;
	private final long refreshInterval;
	private final long initialDelay;
	
	
	public EventConflaterChain() {
		this(DEFAULT_REFRESH_INTERVAL, DEFAULT_INITIAL_DELAY);
	}
	
	public EventConflaterChain(final int refreshInterval, final int initialDelay) {
		this.refreshInterval= refreshInterval;
		this.initialDelay= initialDelay;
	}
	
	public void add(final IEventConflater conflater) {
		this.chain.add(conflater);
	}
	
	public void start() {
		if (!this.started) {
			this.future= scheduler.scheduleWithFixedDelay(getConflaterTask(), this.initialDelay, this.refreshInterval);
			this.started= true;
		}
	}
	
	public void stop() {
		if (this.started) {
			scheduler.unschedule(this.future);
			this.started= false;
		}
	}
	
	@Override
	public void addEvent(final ILayerEvent event) {
		for (final IEventConflater eventConflater : this.chain) {
			eventConflater.addEvent(event);
		}
	}
	
	@Override
	public void clearQueue() {
		for (final IEventConflater eventConflater : this.chain) {
			eventConflater.clearQueue();
		}
	}
	
	@Override
	public int getCount() {
		int count= 0;
		for (final IEventConflater eventConflater : this.chain) {
			count= count + eventConflater.getCount();
		}
		return count;
	}
	
	@Override
	public Runnable getConflaterTask() {
		return new Runnable() {
			@Override
			public void run() {
				for (final IEventConflater conflater : EventConflaterChain.this.chain) {
					conflater.getConflaterTask().run();
				}
			}
		};
	}
	
}