/* * The MIT License * Copyright © 2014-2019 Ilkka Seppälä * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to deal * in the Software without restriction, including without limitation the rights * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell * copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN * THE SOFTWARE. */ import abstractextensions.CommanderExtension; import abstractextensions.SergeantExtension; import abstractextensions.SoldierExtension; import java.util.Optional; import java.util.function.Function; import org.slf4j.LoggerFactory; import units.CommanderUnit; import units.SergeantUnit; import units.SoldierUnit; import units.Unit; /** * Anticipate that an object’s interface needs to be extended in the future. Additional interfaces * are defined by extension objects. */ public class App { /** * Program entry point. * * @param args command line args */ public static void main(String[] args) { //Create 3 different units var soldierUnit = new SoldierUnit("SoldierUnit1"); var sergeantUnit = new SergeantUnit("SergeantUnit1"); var commanderUnit = new CommanderUnit("CommanderUnit1"); //check for each unit to have an extension checkExtensionsForUnit(soldierUnit); checkExtensionsForUnit(sergeantUnit); checkExtensionsForUnit(commanderUnit); } private static void checkExtensionsForUnit(Unit unit) { final var logger = LoggerFactory.getLogger(App.class); var name = unit.getName(); Function func = (e) -> () -> logger.info(name + " without " + e); var extension = "SoldierExtension"; Optional.ofNullable(unit.getUnitExtension(extension)) .map(e -> (SoldierExtension) e) .ifPresentOrElse(SoldierExtension::soldierReady, func.apply(extension)); extension = "SergeantExtension"; Optional.ofNullable(unit.getUnitExtension(extension)) .map(e -> (SergeantExtension) e) .ifPresentOrElse(SergeantExtension::sergeantReady, func.apply(extension)); extension = "CommanderExtension"; Optional.ofNullable(unit.getUnitExtension(extension)) .map(e -> (CommanderExtension) e) .ifPresentOrElse(CommanderExtension::commanderReady, func.apply(extension)); } }