/*******************************************************************************
* Copyright (c) 2016 École Polytechnique de Montréal
*
* 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
*******************************************************************************/
package org.eclipse.tracecompass.internal.provisional.tmf.chart.core.resolver;
import java.util.function.Function;
import org.eclipse.jdt.annotation.Nullable;
/**
* This interface is used for mapping data inside a stream of object. Since the
* stream of data can be any composed object, it is necessary to have a mapper
* that returns a specific member inside a given object.
* <p>
* This class does not extend {@link Function} because a resolver:
* <ul>
* <li>can do more than simply mapping values (e.g. it might compare
* numbers)</li>
* <li>should be only used in the chart plugin</li>
* </ul>
*
* @param <T>
* The type of the input
* @param <R>
* The type of the output when the input is resolved
*
* @author Gabriel-Andrew Pollo-Guilbert
*/
public interface IDataResolver<T, R> {
/**
* Get a function that maps an object to data to be shown on a chart.
*
* @return The mapper function
*/
Function<T, @Nullable R> getMapper();
}