| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, |
| * software distributed under the License is distributed on an |
| * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| * KIND, either express or implied. See the License for the |
| * specific language governing permissions and limitations |
| * under the License. |
| */ |
| package relations; |
| |
| import java.util.*; |
| import javax.persistence.*; |
| |
| // import the enums for MALE and FEMALE |
| import static relations.Deity.Gender.*; |
| |
| |
| /** |
| * A very simple, stand-alone program that stores a new entity in the |
| * database and then performs a query to retrieve it. |
| */ |
| public class Main { |
| |
| @SuppressWarnings("unchecked") |
| public static void main(String[] args) { |
| // Create a new EntityManagerFactory using the System properties. |
| // The "relations" name will be used to configure based on the |
| // corresponding name in the META-INF/persistence.xml file |
| EntityManagerFactory factory = Persistence. |
| createEntityManagerFactory("relations", System.getProperties()); |
| |
| // Create a new EntityManager from the EntityManagerFactory. The |
| // EntityManager is the main object in the persistence API, and is |
| // used to create, delete, and query objects, as well as access |
| // the current transaction |
| EntityManager em = factory.createEntityManager(); |
| |
| initFamilyTree(em); |
| |
| runQueries(em); |
| |
| // It is always good to clean up after ourselves |
| em.close(); |
| factory.close(); |
| } |
| |
| /** |
| * Creates a partial family tree of the Greek dieties. |
| * |
| * @param em the EntityManager to use in the persistence process |
| */ |
| public static void initFamilyTree(EntityManager em) { |
| |
| // First delete all the members from the database the clean up |
| em.getTransaction().begin(); |
| em.createQuery("delete from Deity").executeUpdate(); |
| em.getTransaction().commit(); |
| |
| // Generation 1 |
| Deity uranus = new Deity("Uranus", MALE); |
| Deity gaea = new Deity("Gaea", FEMALE); |
| |
| // Generation 2 |
| Deity cronus = gaea.giveBirth("Cronus", uranus, MALE); |
| Deity rhea = gaea.giveBirth("Rhea", uranus, FEMALE); |
| Deity coeus = gaea.giveBirth("Coeus", uranus, MALE); |
| Deity phoebe = gaea.giveBirth("Phoebe", uranus, FEMALE); |
| Deity oceanus = gaea.giveBirth("Oceanus", uranus, MALE); |
| Deity tethys = gaea.giveBirth("Tethys", uranus, FEMALE); |
| |
| // Generation 3 |
| Deity leto = phoebe.giveBirth("Leto", coeus, FEMALE); |
| |
| Deity hestia = rhea.giveBirth("Hestia", cronus, FEMALE); |
| Deity pluto = rhea.giveBirth("Pluto", cronus, MALE); |
| Deity poseidon = rhea.giveBirth("Poseidon", cronus, MALE); |
| Deity zeus = rhea.giveBirth("Zeus", cronus, MALE); |
| Deity hera = rhea.giveBirth("Hera", cronus, FEMALE); |
| Deity demeter = rhea.giveBirth("Demeter", cronus, FEMALE); |
| |
| // Generation 4 |
| Deity iapetus = tethys.giveBirth("Iapetus", coeus, MALE); |
| Deity clymene = new Deity("Clymene", FEMALE); |
| |
| Deity apollo = leto.giveBirth("Apollo", zeus, MALE); |
| Deity artemis = leto.giveBirth("Artemis", zeus, MALE); |
| |
| Deity persephone = demeter.giveBirth("Persephone", zeus, MALE); |
| |
| Deity ares = hera.giveBirth("Ares", zeus, MALE); |
| Deity hebe = hera.giveBirth("Hebe", zeus, FEMALE); |
| Deity hephaestus = hera.giveBirth("Hephaestus", zeus, MALE); |
| |
| Deity prometheus = clymene.giveBirth("Prometheus", iapetus, MALE); |
| Deity atlas = clymene.giveBirth("Atlas", iapetus, MALE); |
| Deity epimetheus = clymene.giveBirth("Epimetheus", iapetus, FEMALE); |
| |
| Deity dione = new Deity("Dione", FEMALE); |
| dione.giveBirth("Aphrodite", zeus, FEMALE); |
| |
| // Begin a new local transaction so that we can persist a new entity |
| em.getTransaction().begin(); |
| |
| // note that we only need to explicitly persist a single root of the |
| // object graph (the family tree, in this case), since we have the |
| // "cascade" annotation on all the relations |
| em.persist(zeus); |
| |
| // Commit the transaction, which will cause the entity to |
| // be stored in the database |
| em.getTransaction().commit(); |
| } |
| |
| /** |
| * Run some sample queries against the family tree model. |
| * |
| * @param em the EntityManager to use |
| */ |
| public static void runQueries(EntityManager em) { |
| |
| System.out.println("Running query to find all instances.."); |
| |
| // Perform a simple query for all the Deity entities |
| Query q = em.createQuery("select x from Deity x"); |
| |
| // Go through each of the entities and print out each of their |
| // messages, as well as the date on which it was created |
| for (Deity m : (List<Deity>) q.getResultList()) { |
| System.out.println(m.getName()); |
| } |
| |
| q = em.createQuery("select x from Deity x " |
| + "where x.father.name = 'Zeus'"); |
| |
| for (Deity m : (List<Deity>) q.getResultList()) { |
| System.out.println("Child of Zeus: " + m.getName()); |
| } |
| |
| q = em.createNamedQuery("siblings"). |
| setParameter(1, em.getReference(Deity.class, "Rhea")); |
| |
| for (Deity m : (List<Deity>) em.createNamedQuery("siblings"). |
| setParameter(1, em.getReference(Deity.class, "Rhea")). |
| getResultList()) { |
| System.out.println("Siblings of Rhea: " + m.getName()); |
| } |
| |
| for (Deity m : (List<Deity>) em.createNamedQuery("half-siblings"). |
| setParameter(1, em.getReference(Deity.class, "Apollo")). |
| getResultList()) { |
| System.out.println("Half-siblings of Apollo: " + m.getName()); |
| } |
| |
| for (Deity m : (List<Deity>) em.createNamedQuery("cousins"). |
| setParameter(1, em.getReference(Deity.class, "Leto")). |
| getResultList()) { |
| System.out.println("Cousins of Leto: " + m.getName()); |
| } |
| } |
| } |