/** * The MIT License Copyright (c) 2016 Amit Dixit * * 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.datamapper; import java.util.Optional; import org.apache.log4j.Logger; /** * The Data Mapper (DM) is a layer of software that separates the in-memory objects from the * database. Its responsibility is to transfer data between the two and also to isolate them from * each other. With Data Mapper the in-memory objects needn't know even that there's a database * present; they need no SQL interface code, and certainly no knowledge of the database schema. (The * database schema is always ignorant of the objects that use it.) Since it's a form of Mapper , * Data Mapper itself is even unknown to the domain layer. *

* The below example demonstrates basic CRUD operations: Create, Read, Update, and Delete. * */ public final class App { private static Logger log = Logger.getLogger(App.class); /** * Program entry point. * * @param args command line args. */ public static void main(final String... args) { /* Create new data mapper for type 'first' */ final StudentDataMapper mapper = new StudentDataMapperImpl(); /* Create new student */ Student student = new Student(1, "Adam", 'A'); /* Add student in respectibe store */ mapper.insert(student); log.debug("App.main(), student : " + student + ", is inserted"); /* Find this student */ final Optional studentToBeFound = mapper.find(student.getStudentId()); log.debug("App.main(), student : " + studentToBeFound + ", is searched"); /* Update existing student object */ student = new Student(student.getStudentId(), "AdamUpdated", 'A'); /* Update student in respectibe db */ mapper.update(student); log.debug("App.main(), student : " + student + ", is updated"); log.debug("App.main(), student : " + student + ", is going to be deleted"); /* Delete student in db */ mapper.delete(student); } private App() {} }