/*******************************************************************************
 * Copyright (c) 2007, 2008 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.wst.validation;

import java.util.List;

/**
 * A service that collects performance information on validation operations.
 * <p>
 * <b>Provisional API:</b> This class/interface is part of an interim API that is still under development and expected to 
 * change significantly before reaching stability. It is being made available at this early stage to solicit feedback 
 * from pioneering adopters on the understanding that any code that uses this API will almost certainly be broken 
 * (repeatedly) as the API evolves.
 * </p>
 * @noextend This interface is not intended to be extended by clients.
 * @noimplement This interface is not intended to be implemented by clients.
 * @author karasiuk
 *
 */
public interface IPerformanceMonitor {
	
	/**
	 * The level of information to collect.
	 */
	public enum CollectionLevel {None, Default}
	
	/** 
	 * Add this performance counter to the monitor. The monitor will decide what to 
	 * do with the results, it may log them to a file, or it may simply hold on to them.
	 * 
	 * @param counters
	 */
	public void add(PerformanceCounters counters);
	
	/**
	 * Answer true if the performance monitor is collecting performance events.
	 */
	public boolean isCollecting();
	
	/** Answer true if only summary information is requested. */
	public boolean isSummaryOnly();
	
	/**
	 * Set the performance event collection level. This controls which
	 * performance events are collected, including none of them.
	 * 
	 * @param level
	 * 		The level to collect. The default is to not collect anything.
	 */
	public void setCollectionLevel(CollectionLevel level);
	
	/**
	 * Answer the level of performance events that are being collected by the validation framework.
	 */
	public CollectionLevel getCollectionLevel();
	
	/**
	 * Answer the performance counters that have been collected so far. Some
	 * monitors do not save counters, and they will always return an empty list.
	 * 
	 * @param asSummary
	 * 		If this parameter is true, only answer a summary of the counters.
	 */
	public List<PerformanceCounters> getPerformanceCounters(boolean asSummary);
	
	/**
	 * Delete the collected performance counters.
	 */
	public void resetPerformanceCounters();

}