/* * The MIT License * Copyright © 2014-2021 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. */ package com.iluwatar.parameter.object; import org.slf4j.Logger; import org.slf4j.LoggerFactory; /** * The syntax of Java language doesn’t allow you to declare a method with a predefined value * for a parameter. Probably the best option to achieve default method parameters in Java is * by using the method overloading. Method overloading allows you to declare several methods * with the same name but with a different number of parameters. But the main problem with * method overloading as a solution for default parameter values reveals itself when a method * accepts multiple parameters. Creating an overloaded method for each possible combination of * parameters might be cumbersome. To deal with this issue, the Parameter Object pattern is used. * The Parameter Object is simply a wrapper object for all parameters of a method. * It is nothing more than just a regular POJO. The advantage of the Parameter Object over a * regular method parameter list is the fact that class fields can have default values. * Once the wrapper class is created for the method parameter list, a corresponding builder class * is also created. Usually it's an inner static class. The final step is to use the builder * to construct a new parameter object. For those parameters that are skipped, * their default values are going to be used. */ public class App { private static final Logger LOGGER = LoggerFactory.getLogger(App.class); /** * Program entry point. * * @param args command line args */ public static void main(String[] args) { ParameterObject params = ParameterObject.newBuilder() .withType("sneakers") .sortBy("brand") .build(); LOGGER.info(params.toString()); LOGGER.info(new SearchService().search(params)); } }