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package org.ufcspa.simdecs.bn.jpa;

import java.io.Serializable;
import javax.persistence.Query;
import javax.persistence.EntityNotFoundException;
import javax.persistence.criteria.CriteriaQuery;
import javax.persistence.criteria.Root;
import org.ufcspa.simdecs.bn.entity.BayesianNetwork;
import org.ufcspa.simdecs.bn.entity.Question;
import java.util.ArrayList;
import java.util.List;
import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.transaction.UserTransaction;
import org.ufcspa.simdecs.bn.entity.Node;
import org.ufcspa.simdecs.bn.jpa.exceptions.NonexistentEntityException;
import org.ufcspa.simdecs.bn.jpa.exceptions.RollbackFailureException;

/**
 *
 * @author mchelem
 */
public class NodeJpaController implements Serializable {

    public NodeJpaController(UserTransaction utx, EntityManagerFactory emf) {
        this.utx = utx;
        this.emf = emf;
    }
    private UserTransaction utx = null;
    private EntityManagerFactory emf = null;

    public EntityManager getEntityManager() {
        return emf.createEntityManager();
    }

    public void create(Node node) throws RollbackFailureException, Exception {
        if (node.getQuestions() == null) {
            node.setQuestions(new ArrayList<Question>());
        }
        EntityManager em = null;
        try {
            utx.begin();
            em = getEntityManager();
            BayesianNetwork bayesianNetwork = node.getBayesianNetwork();
            if (bayesianNetwork != null) {
                bayesianNetwork = em.getReference(bayesianNetwork.getClass(), bayesianNetwork.getId());
                node.setBayesianNetwork(bayesianNetwork);
            }
            List<Question> attachedQuestions = new ArrayList<Question>();
            for (Question questionsQuestionToAttach : node.getQuestions()) {
                questionsQuestionToAttach = em.getReference(questionsQuestionToAttach.getClass(), questionsQuestionToAttach.getId());
                attachedQuestions.add(questionsQuestionToAttach);
            }
            node.setQuestions(attachedQuestions);
            em.persist(node);
            if (bayesianNetwork != null) {
                bayesianNetwork.getNodes().add(node);
                bayesianNetwork = em.merge(bayesianNetwork);
            }
            for (Question questionsQuestion : node.getQuestions()) {
                Node oldNodeOfQuestionsQuestion = questionsQuestion.getNode();
                questionsQuestion.setNode(node);
                questionsQuestion = em.merge(questionsQuestion);
                if (oldNodeOfQuestionsQuestion != null) {
                    oldNodeOfQuestionsQuestion.getQuestions().remove(questionsQuestion);
                    oldNodeOfQuestionsQuestion = em.merge(oldNodeOfQuestionsQuestion);
                }
            }
            utx.commit();
        } catch (Exception ex) {
            try {
                utx.rollback();
            } catch (Exception re) {
                throw new RollbackFailureException("An error occurred attempting to roll back the transaction.", re);
            }
            throw ex;
        } finally {
            if (em != null) {
                em.close();
            }
        }
    }

    public void edit(Node node) throws NonexistentEntityException, RollbackFailureException, Exception {
        EntityManager em = null;
        try {
            utx.begin();
            em = getEntityManager();
            Node persistentNode = em.find(Node.class, node.getId());
            BayesianNetwork bayesianNetworkOld = persistentNode.getBayesianNetwork();
            BayesianNetwork bayesianNetworkNew = node.getBayesianNetwork();
            List<Question> questionsOld = persistentNode.getQuestions();
            List<Question> questionsNew = node.getQuestions();
            if (bayesianNetworkNew != null) {
                bayesianNetworkNew = em.getReference(bayesianNetworkNew.getClass(), bayesianNetworkNew.getId());
                node.setBayesianNetwork(bayesianNetworkNew);
            }
            List<Question> attachedQuestionsNew = new ArrayList<Question>();
            for (Question questionsNewQuestionToAttach : questionsNew) {
                questionsNewQuestionToAttach = em.getReference(questionsNewQuestionToAttach.getClass(), questionsNewQuestionToAttach.getId());
                attachedQuestionsNew.add(questionsNewQuestionToAttach);
            }
            questionsNew = attachedQuestionsNew;
            node.setQuestions(questionsNew);
            node = em.merge(node);
            if (bayesianNetworkOld != null && !bayesianNetworkOld.equals(bayesianNetworkNew)) {
                bayesianNetworkOld.getNodes().remove(node);
                bayesianNetworkOld = em.merge(bayesianNetworkOld);
            }
            if (bayesianNetworkNew != null && !bayesianNetworkNew.equals(bayesianNetworkOld)) {
                bayesianNetworkNew.getNodes().add(node);
                bayesianNetworkNew = em.merge(bayesianNetworkNew);
            }
            for (Question questionsOldQuestion : questionsOld) {
                if (!questionsNew.contains(questionsOldQuestion)) {
                    questionsOldQuestion.setNode(null);
                    questionsOldQuestion = em.merge(questionsOldQuestion);
                }
            }
            for (Question questionsNewQuestion : questionsNew) {
                if (!questionsOld.contains(questionsNewQuestion)) {
                    Node oldNodeOfQuestionsNewQuestion = questionsNewQuestion.getNode();
                    questionsNewQuestion.setNode(node);
                    questionsNewQuestion = em.merge(questionsNewQuestion);
                    if (oldNodeOfQuestionsNewQuestion != null && !oldNodeOfQuestionsNewQuestion.equals(node)) {
                        oldNodeOfQuestionsNewQuestion.getQuestions().remove(questionsNewQuestion);
                        oldNodeOfQuestionsNewQuestion = em.merge(oldNodeOfQuestionsNewQuestion);
                    }
                }
            }
            utx.commit();
        } catch (Exception ex) {
            try {
                utx.rollback();
            } catch (Exception re) {
                throw new RollbackFailureException("An error occurred attempting to roll back the transaction.", re);
            }
            String msg = ex.getLocalizedMessage();
            if (msg == null || msg.length() == 0) {
                Long id = node.getId();
                if (findNode(id) == null) {
                    throw new NonexistentEntityException("The node with id " + id + " no longer exists.");
                }
            }
            throw ex;
        } finally {
            if (em != null) {
                em.close();
            }
        }
    }

    public void destroy(Long id) throws NonexistentEntityException, RollbackFailureException, Exception {
        EntityManager em = null;
        try {
            utx.begin();
            em = getEntityManager();
            Node node;
            try {
                node = em.getReference(Node.class, id);
                node.getId();
            } catch (EntityNotFoundException enfe) {
                throw new NonexistentEntityException("The node with id " + id + " no longer exists.", enfe);
            }
            BayesianNetwork bayesianNetwork = node.getBayesianNetwork();
            if (bayesianNetwork != null) {
                bayesianNetwork.getNodes().remove(node);
                bayesianNetwork = em.merge(bayesianNetwork);
            }
            List<Question> questions = node.getQuestions();
            for (Question questionsQuestion : questions) {
                questionsQuestion.setNode(null);
                questionsQuestion = em.merge(questionsQuestion);
            }
            em.remove(node);
            utx.commit();
        } catch (Exception ex) {
            try {
                utx.rollback();
            } catch (Exception re) {
                throw new RollbackFailureException("An error occurred attempting to roll back the transaction.", re);
            }
            throw ex;
        } finally {
            if (em != null) {
                em.close();
            }
        }
    }

    public List<Node> findNodeEntities() {
        return findNodeEntities(true, -1, -1);
    }

    public List<Node> findNodeEntities(int maxResults, int firstResult) {
        return findNodeEntities(false, maxResults, firstResult);
    }

    private List<Node> findNodeEntities(boolean all, int maxResults, int firstResult) {
        EntityManager em = getEntityManager();
        try {
            CriteriaQuery cq = em.getCriteriaBuilder().createQuery();
            cq.select(cq.from(Node.class));
            Query q = em.createQuery(cq);
            if (!all) {
                q.setMaxResults(maxResults);
                q.setFirstResult(firstResult);
            }
            return q.getResultList();
        } finally {
            em.close();
        }
    }

    public Node findNode(Long id) {
        EntityManager em = getEntityManager();
        try {
            return em.find(Node.class, id);
        } finally {
            em.close();
        }
    }

    public int getNodeCount() {
        EntityManager em = getEntityManager();
        try {
            CriteriaQuery cq = em.getCriteriaBuilder().createQuery();
            Root<Node> rt = cq.from(Node.class);
            cq.select(em.getCriteriaBuilder().count(rt));
            Query q = em.createQuery(cq);
            return ((Long) q.getSingleResult()).intValue();
        } finally {
            em.close();
        }
    }
    
}