de.taimos.dao.hibernate.EntityDAOHibernate.java Source code

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Here is the source code for de.taimos.dao.hibernate.EntityDAOHibernate.java

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package de.taimos.dao.hibernate;

/*
 * #%L Hibernate DAO for Spring %% Copyright (C) 2013 Taimos GmbH %% 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. #L%
 */

import java.util.List;

import javax.persistence.EntityManager;
import javax.persistence.EntityNotFoundException;
import javax.persistence.PersistenceContext;
import javax.persistence.TypedQuery;

import org.springframework.transaction.annotation.Transactional;

import de.taimos.dao.IEntity;
import de.taimos.dao.IEntityDAO;

/**
 * @author hoegertn
 * 
 * @param <E> the entity type
 * @param <I> the id type
 */
public abstract class EntityDAOHibernate<E extends IEntity<I>, I> implements IEntityDAO<E, I> {

    @PersistenceContext
    protected EntityManager entityManager;

    @Override
    @Transactional
    public E save(final E element) {
        return this.entityManager.merge(element);
    }

    @Override
    @Transactional
    public void delete(final E element) {
        this.entityManager.remove(this.entityManager.merge(element));
    }

    @Override
    @Transactional
    public void deleteById(final I id) {
        final E element = this.findById(id);
        if (element == null) {
            throw new EntityNotFoundException();
        }
        this.entityManager.remove(element);
    }

    @Override
    public E findById(final I id) {
        return this.entityManager.find(this.getEntityClass(), id);
    }

    @Override
    public List<E> findList(final int first, final int max) {
        final TypedQuery<E> query = this.entityManager.createQuery(this.getFindListQuery(), this.getEntityClass());
        if (first >= 0) {
            query.setFirstResult(first);
        }
        if (max >= 0) {
            query.setMaxResults(max);
        }
        return query.getResultList();
    }

    @Override
    public List<E> findList() {
        return this.findList(-1, -1);
    }

    /**
     * @param query
     * @param params
     * @return the entity or null if not found or more than one found
     */
    protected final E findByQuery(final String query, final Object... params) {
        final List<E> list = this.findListByQuery(query, params);
        if (list.size() == 1) {
            return list.get(0);
        }
        return null;
    }

    /**
     * @param query
     * @param params
     * @return the entity or null if not found or more than one found
     */
    protected final Object[] findGenericByQuery(final String query, final Object... params) {
        final List<Object[]> list = this.findGenericListByQuery(query, params);
        if (list.size() == 1) {
            return list.get(0);
        }
        return null;
    }

    protected final List<E> findListByQuery(final String query, final Object... params) {
        return this.findListByQueryLimit(query, -1, -1, params);
    }

    protected final List<Object[]> findGenericListByQuery(final String query, final Object... params) {
        return this.findGenericListByQueryLimit(query, -1, -1, params);
    }

    protected final List<Object[]> findGenericListByQueryLimit(final String query, final int first, final int max,
            final Object... params) {
        return this.findListByQueryLimit(query, Object[].class, first, max, params);
    }

    protected final List<E> findListByQueryLimit(final String query, final int first, final int max,
            final Object... params) {
        return this.findListByQueryLimit(query, this.getEntityClass(), first, max, params);
    }

    private <T> List<T> findListByQueryLimit(final String query, Class<T> clazz, final int first, final int max,
            final Object... params) {
        final TypedQuery<T> tq = this.entityManager.createQuery(query, clazz);
        for (int i = 0; i < params.length; i++) {
            tq.setParameter(i + 1, params[i]);
        }
        if (first >= 0) {
            tq.setFirstResult(first);
        }
        if (max >= 0) {
            tq.setMaxResults(max);
        }
        return tq.getResultList();
    }

    /**
     * Override in sub-class if not "id"
     * 
     * @return the id field
     */
    protected String getIdField() {
        return "id";
    }

    /**
     * Override in sub-class if not "FROM 'EntityName'"
     * 
     * @return the select query
     */
    protected String getFindListQuery() {
        return "FROM " + this.getEntityClass().getSimpleName();
    }

}