initial commit

src/main/java/com/commafeed/backend/dao/GenericDAO.java

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+package com.commafeed.backend.dao;
+
+import java.util.List;
+
+import javax.annotation.PostConstruct;
+import javax.persistence.EntityManager;
+import javax.persistence.PersistenceContext;
+import javax.persistence.criteria.CriteriaBuilder;
+import javax.persistence.criteria.CriteriaQuery;
+import javax.persistence.criteria.Root;
+
+import com.google.common.reflect.TypeToken;
+import com.uaihebert.factory.EasyCriteriaFactory;
+import com.uaihebert.model.EasyCriteria;
+
+public abstract class GenericDAO<T, K> {
+
+	private TypeToken<T> type = new TypeToken<T>(getClass()) {
+	};
+
+	@PersistenceContext
+	protected EntityManager em;
+
+	protected CriteriaBuilder builder;
+
+	@PostConstruct
+	public void init() {
+		builder = em.getCriteriaBuilder();
+	}
+
+	public void save(T object) {
+		em.persist(object);
+	}
+
+	public void update(T... objects) {
+		for (Object object : objects) {
+			em.merge(object);
+		}
+	}
+
+	public void delete(T object) {
+		object = em.merge(object);
+		em.remove(object);
+	}
+
+	public void deleteById(Object id) {
+		Object ref = em.getReference(getType(), id);
+		em.remove(ref);
+	}
+
+	public T findById(K id) {
+		T t = em.find(getType(), id);
+		return t;
+	}
+
+	public List<T> findAll() {
+		return EasyCriteriaFactory.createQueryCriteria(em, getType())
+				.getResultList();
+	}
+
+	public List<T> findAll(int startIndex, int count) {
+		EasyCriteria<T> criteria = EasyCriteriaFactory.createQueryCriteria(em,
+				getType());
+		criteria.setMaxResults(count);
+		criteria.setFirstResult(startIndex);
+		return criteria.getResultList();
+	}
+
+	public long getCount() {
+		CriteriaBuilder builder = em.getCriteriaBuilder();
+		CriteriaQuery<Long> query = builder.createQuery(Long.class);
+		Root<T> root = query.from(getType());
+		query.select(builder.count(root));
+		return em.createQuery(query).getSingleResult();
+	}
+
+	public List<T> findByField(String field, Object value) {
+		EasyCriteria<T> criteria = EasyCriteriaFactory.createQueryCriteria(em,
+				getType());
+		criteria.andEquals(field, value);
+		return criteria.getResultList();
+	}
+
+	@SuppressWarnings("unchecked")
+	protected Class<T> getType() {
+		return (Class<T>) type.getRawType();
+	}
+
+}