Java tutorial
/* * JBoss, Home of Professional Open Source * Copyright 2014, Red Hat, Inc. and/or its affiliates, and individual * contributors by the @authors tag. See the copyright.txt in the * distribution for a full listing of individual contributors. * * Licensed 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 org.jboss.quickstarts.wfk.contact; import javax.inject.Inject; import javax.persistence.EntityManager; import javax.persistence.TypedQuery; import javax.persistence.criteria.CriteriaBuilder; import javax.persistence.criteria.CriteriaQuery; import javax.persistence.criteria.Root; import javax.validation.ConstraintViolationException; import javax.validation.ValidationException; import org.springframework.stereotype.Component; import java.util.List; import java.util.logging.Logger; /** * This is a Repository and connects the Service/Control layer with the Domain/Entity Object. There are no access modifiers * on the methods making them 'package' scope. They should only be accessed by a Service/Control object. * * @author Joshua Wilson * */ @Component public class ContactRepository { // @Inject // private Logger log; @Inject private EntityManager em; /** * Find all the Contacts and sort them alphabetically by last name. * * @return List of Contacts */ List<Contact> findAllOrderedByName() { TypedQuery<Contact> query = em.createNamedQuery(Contact.FIND_ALL, Contact.class); List<Contact> contacts = query.getResultList(); return contacts; } /** * Find just one Contact by it's ID. * * @param id * @return Contact */ Contact findById(Long id) { return em.find(Contact.class, id); } /** * Find just one Contact by the email that is passed in. If there is more then one, only the first will be returned. * * @param email * @return Contact */ Contact findByEmail(String email) { TypedQuery<Contact> query = em.createNamedQuery(Contact.FIND_BY_EMAIL, Contact.class).setParameter("email", email); Contact contact = query.getSingleResult(); return contact; } /** * Find just one Contact by the first name that is passed in. If there is more then one, only the first will be returned. * * @param firstName * @return Contact */ Contact findByFirstName(String firstName) { CriteriaBuilder cb = em.getCriteriaBuilder(); CriteriaQuery<Contact> criteria = cb.createQuery(Contact.class); Root<Contact> contact = criteria.from(Contact.class); // Swap criteria statements if you would like to try out type-safe criteria queries, a new feature in JPA 2.0. // criteria.select(contact).where(cb.equal(contact.get(Contact_.firstName), firstName)); criteria.select(contact).where(cb.equal(contact.get("firstName"), firstName)); return em.createQuery(criteria).getSingleResult(); } /** * Find just one Contact by the last name that is passed in. If there is more then one, only the first will be returned. * * @param lastName * @return Contact */ Contact findByLastName(String lastName) { CriteriaBuilder cb = em.getCriteriaBuilder(); CriteriaQuery<Contact> criteria = cb.createQuery(Contact.class); Root<Contact> contact = criteria.from(Contact.class); // Swap criteria statements if you would like to try out type-safe criteria queries, a new feature in JPA 2.0. // criteria.select(contact).where(cb.equal(contact.get(Contact_.lastName), lastName)); criteria.select(contact).where(cb.equal(contact.get("lastName"), lastName)); return em.createQuery(criteria).getSingleResult(); } /** * Create a Contact and store it in the database. * * Persist takes an entity instance, adds it to the context and makes that instance managed (ie future updates * to the entity will be tracked) * * persist() will set the @GeneratedValue @Id for an object. * * @param Contact * @return Contact * @throws ConstraintViolationException, ValidationException, Exception */ Contact create(Contact contact) throws ConstraintViolationException, ValidationException, Exception { // log.info("ContactRepository.create() - Creating " + contact.getFirstName() + " " + contact.getLastName()); // Write the contact to the database. em.persist(contact); return contact; } /** * Update a Contact in the database. * * Merge creates a new instance of your entity, copies the state from the supplied entity, and makes the new * copy managed. The instance you pass in will not be managed (any changes you make will not be part of the * transaction - unless you call merge again). * * merge() however must have an object with the @Id already generated. * * @param Contact * @return Contact * @throws ConstraintViolationException, ValidationException, Exception */ // Map<String, Object> update(Contact contact) throws Exception { Contact update(Contact contact) throws ConstraintViolationException, ValidationException, Exception { // log.info("ContactRepository.update() - Updating " + contact.getFirstName() + " " + contact.getLastName()); // Either update the contact or add it if it can't be found. em.merge(contact); return contact; } /** * Delete a Contact in the database. * * @param Contact * @return Contact * @throws Exception */ // Map<String, Object> delete(Contact contact) throws Exception { Contact delete(Contact contact) throws Exception { // log.info("ContactRepository.delete() - Deleting " + contact.getFirstName() + " " + contact.getLastName()); if (contact.getId() != null) { /* * The Hibernate session (aka EntityManager's persistent context) is closed and invalidated after the commit(), * because it is bound to a transaction. The object goes into a detached status. If you open a new persistent * context, the object isn't known as in a persistent state in this new context, so you have to merge it. * * Merge sees that the object has a primary key (id), so it knows it is not new and must hit the database * to reattach it. * * Note, there is NO remove method which would just take a primary key (id) and a entity class as argument. * You first need an object in a persistent state to be able to delete it. * * Therefore we merge first and then we can remove it. */ em.remove(em.merge(contact)); // } else { // log.info("ContactRepository.delete() - No ID was found so can't Delete."); } return contact; } }