160 lines
5.7 KiB
Java
160 lines
5.7 KiB
Java
package eu.eudat.queryable.hibernatequeryablelist;
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import eu.eudat.entities.DataEntity;
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import eu.eudat.queryable.QueryableList;
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import eu.eudat.queryable.exceptions.NotSingleResultException;
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import eu.eudat.queryable.predicates.OrderByPredicate;
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import eu.eudat.queryable.predicates.SelectPredicate;
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import eu.eudat.queryable.predicates.SinglePredicate;
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import javax.persistence.EntityManager;
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import javax.persistence.TypedQuery;
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import javax.persistence.criteria.*;
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import java.util.LinkedList;
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import java.util.List;
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import java.util.Set;
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import java.util.stream.Collectors;
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public class QueryableHibernateList<T extends DataEntity<T>> implements QueryableList<T> {
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private EntityManager manager;
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private CriteriaQuery<T> query;
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private Class<T> tClass;
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private Root<T> root;
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private List<Predicate> predicates = new LinkedList<Predicate>();
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private List<Order> orderings = new LinkedList<>();
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private List<Selection> fields = new LinkedList<>();
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private Integer length;
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private Integer offset;
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private Set<String> hints;
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private String hint;
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public QueryableHibernateList(EntityManager manager, Class<T> tClass) {
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this.manager = manager;
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this.tClass = tClass;
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}
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public QueryableHibernateList<T> setManager(EntityManager manager) {
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this.manager = manager;
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return this;
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}
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public QueryableList<T> withHint(String hint) {
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this.hint = hint;
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return this;
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}
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public QueryableList<T> setHints(Set<String> hints) {
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this.hints = hints;
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return this;
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}
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public QueryableHibernateList<T> setEntity(Class<T> type) {
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CriteriaBuilder builder = this.manager.getCriteriaBuilder();
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this.query = builder.createQuery(type);
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this.root = this.query.from(this.tClass);
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return this;
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}
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public void initiateQueryableList(Class<T> type) {
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CriteriaBuilder builder = this.manager.getCriteriaBuilder();
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this.query = builder.createQuery(type);
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}
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@Override
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public QueryableList<T> skip(Integer offset) {
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this.offset = offset;
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return this;
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}
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@Override
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public QueryableList<T> take(Integer length) {
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this.length = length;
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return this;
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}
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public QueryableList<T> where(SinglePredicate<T> predicate) {
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this.predicates.add(predicate.applyPredicate(this.manager.getCriteriaBuilder(), this.root));
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return this;
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}
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public <R> List<R> select(SelectPredicate<T, R> predicate) {
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List<T> list = this.toList();
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List<R> newlist = new LinkedList<R>();
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for (T item : list) {
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newlist.add(predicate.applySelection(item));
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}
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return newlist;
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}
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public QueryableList<T> distinct() {
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this.query.distinct(true);
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return this;
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}
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public QueryableList<T> orderByAsc(OrderByPredicate<T> predicate) {
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this.orderings.add(this.manager.getCriteriaBuilder().asc(predicate.applyPredicate(this.root)));
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return this;
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}
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public QueryableList<T> orderByDesc(OrderByPredicate<T> predicate) {
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this.orderings.add(this.manager.getCriteriaBuilder().desc(predicate.applyPredicate(this.root)));
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return this;
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}
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public Long count() {
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CriteriaBuilder criteriaBuilder = this.manager.getCriteriaBuilder();
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CriteriaQuery<Long> criteriaQuery = criteriaBuilder.createQuery(Long.class);
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criteriaQuery.select(criteriaBuilder.count(criteriaQuery.from(this.tClass)));
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criteriaQuery.where(this.predicates.toArray(new Predicate[this.predicates.size()]));
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return this.manager.createQuery(criteriaQuery).getSingleResult();
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}
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public List<T> toList() {
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this.query.where(this.predicates.toArray(new Predicate[this.predicates.size()]));
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if (!this.orderings.isEmpty()) this.query.orderBy(this.orderings);
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TypedQuery<T> typedQuery = this.manager.createQuery(this.query);
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if (this.offset != null) typedQuery.setFirstResult(this.offset);
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if (this.length != null) typedQuery.setMaxResults(this.length);
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if (this.hint != null && this.hints.contains(hint)) {
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List ids = typedQuery.getResultList().stream().map(item -> item.getKeys()[0]).collect(Collectors.toList());
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if (ids != null && !ids.isEmpty()) typedQuery = queryWithHint(ids);
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}
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return typedQuery.getResultList();
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}
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public T getSingle() {
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Predicate[] array = new Predicate[this.predicates.size()];
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this.predicates.toArray(array);
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this.query.where(array);
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TypedQuery<T> typedQuery = this.manager.createQuery(this.query);
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return typedQuery.getSingleResult();
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}
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public T getSingleOrDefault() {
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Predicate[] array = new Predicate[this.predicates.size()];
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this.predicates.toArray(array);
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this.query.where(array);
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TypedQuery<T> typedQuery = this.manager.createQuery(this.query);
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List<T> results = typedQuery.getResultList();
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if (results.size() == 0) return null;
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if (results.size() == 1) return results.get(0);
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else throw new NotSingleResultException("Query returned more than one items");
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}
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private TypedQuery<T> queryWithHint(List ids) {
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CriteriaBuilder criteriaBuilder = this.manager.getCriteriaBuilder();
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CriteriaQuery<T> criteriaQuery = criteriaBuilder.createQuery(tClass);
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Root<T> criteriaRoot = criteriaQuery.from(this.tClass);
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criteriaQuery.where(criteriaRoot.get("id").in(ids));
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TypedQuery<T> typedQuery = this.manager.createQuery(criteriaQuery);
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typedQuery.setHint("javax.persistence.fetchgraph", this.manager.getEntityGraph(this.hint));
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return typedQuery;
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}
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}
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