first try at new Jpql-query-api

Author: Gerald Unterrainer

src/main/java/info/unterrainer/commons/httpserver/daos/BasicDao.java

@@ -1,49 +1,40 @@
 package info.unterrainer.commons.httpserver.daos;
 
-import javax.persistence.TypedQuery;
-
 import info.unterrainer.commons.httpserver.jsons.ListJson;
 import info.unterrainer.commons.rdbutils.entities.BasicJpa;
 
 public interface BasicDao<P extends BasicJpa, E> {
 
 	P getById(Long id);
 
-	ListJson<P> getList(long offset, long size);
-
-	ListJson<P> getList(long offset, long size, String whereClause, ParamMap params);
-
 	P create(P entity);
 
 	P update(P entity);
 
+	ListJson<P> getList(E em, long offset, long size, String selectClause, String joinClause, String whereClause,
+			ParamMap params, String orderByClause);
+
 	UpsertResult<P> upsert(String whereClause, ParamMap params, P entity);
 
-	UpsertResult<P> upsert(TypedQuery<P> query, P entity);
+	UpsertResult<P> upsert(Query<P, P> query, P entity);
 
 	void delete(Long id);
 
 	P getById(E em, Long id);
 
-	ListJson<P> getList(E em, long offset, long size);
+	<T> QueryBuilder<P, T> query(Class<T> resultType);
 
-	ListJson<P> getList(E em, long offset, long size, String whereClause, ParamMap params);
+	QueryBuilder<P, P> query();
 
-	ListJson<P> getList(E em, long offset, long size, String joinClause, String whereClause, ParamMap params);
-
-	ListJson<P> getList(E em, long offset, long size, String selectClause, String joinClause, String whereClause,
-			ParamMap params);
-
-	ListJson<P> getList(E em, long offset, long size, String selectClause, String joinClause, String whereClause,
-			ParamMap params, String orderByClause);
+	CountQueryBuilder<P, P> countQuery();
 
 	P create(E em, P entity);
 
 	P update(E em, P entity);
 
 	UpsertResult<P> upsert(E em, String whereClause, ParamMap params, P entity);
 
-	UpsertResult<P> upsert(E em, TypedQuery<P> query, P entity);
+	UpsertResult<P> upsert(E em, Query<P, P> query, P entity);
 
 	void delete(E em, Long id);
 }

src/main/java/info/unterrainer/commons/httpserver/daos/BasicQueryBuilder.java

@@ -0,0 +1,250 @@
+package info.unterrainer.commons.httpserver.daos;
+
+import javax.persistence.EntityManager;
+import javax.persistence.EntityManagerFactory;
+
+import info.unterrainer.commons.rdbutils.entities.BasicJpa;
+import lombok.AccessLevel;
+import lombok.RequiredArgsConstructor;
+
+@RequiredArgsConstructor(access = AccessLevel.PACKAGE)
+public class BasicQueryBuilder<P extends BasicJpa, T, R extends BasicQueryBuilder<P, T, R>> {
+
+	protected final EntityManagerFactory emf;
+	protected final JpqlDao<P> dao;
+
+	protected EntityManager entityManager;
+	protected String selectClause = "o";
+	protected String joinClause;
+	protected String whereClause;
+	protected String orderByClause = "o.id ASC";
+	protected boolean lockPessimistic = false;
+
+	protected ParamMap parameters = ParamMap.builder().build();
+
+	/**
+	 * Sets a custom {@link EntityManager}.
+	 * <p>
+	 * Default is to create one when creating the query.<br>
+	 * To reset it to default, set it to null.
+	 *
+	 * @param em an {@link EntityManager}
+	 * @return an instance of this builder to provide a fluent interface
+	 */
+	@SuppressWarnings("unchecked")
+	public R entityManager(final EntityManager em) {
+		entityManager = em;
+		return (R) this;
+	}
+
+	/**
+	 * Sets a custom select-clause.
+	 * <p>
+	 * Default is "o"<br>
+	 * To reset it to default, set it to null.<br>
+	 * To completely delete it, set it to an empty string.
+	 *
+	 * @param selectClause the new clause
+	 * @return an instance of this builder to provide a fluent interface
+	 */
+	@SuppressWarnings("unchecked")
+	public R select(final String selectClause) {
+		this.selectClause = selectClause;
+		if (this.selectClause == null || this.selectClause.isBlank())
+			this.selectClause = "o";
+		return (R) this;
+	}
+
+	/**
+	 * Sets a custom join-clause.
+	 * <p>
+	 * Default is ""<br>
+	 * To reset it to default, set it to null or directly to an empty string.
+	 *
+	 * @param joinClause the new clause
+	 * @return an instance of this builder to provide a fluent interface
+	 */
+	@SuppressWarnings("unchecked")
+	public R join(final String joinClause) {
+		this.joinClause = joinClause;
+		if (this.joinClause == null)
+			this.joinClause = "";
+		return (R) this;
+	}
+
+	/**
+	 * Sets a custom where-clause.
+	 * <p>
+	 * Default is ""<br>
+	 * To reset it to default, set it to null or directly to an empty string.
+	 *
+	 * @param whereClause the new clause
+	 * @return an instance of this builder to provide a fluent interface
+	 */
+	@SuppressWarnings("unchecked")
+	public R where(final String whereClause) {
+		this.whereClause = whereClause;
+		if (this.whereClause == null)
+			this.whereClause = "";
+		return (R) this;
+	}
+
+	/**
+	 * Adds an 'AND' part to the where-clause.
+	 * <p>
+	 * For example: .and("o.loggedIn=:loggedIn");
+	 *
+	 * @param andWhereClause the clause to add
+	 * @return an instance of this builder to provide a fluent interface
+	 */
+	@SuppressWarnings("unchecked")
+	public R and(final String andWhereClause) {
+		if (whereClause == null || whereClause.isBlank())
+			whereClause = andWhereClause;
+		else
+			whereClause += " AND " + andWhereClause;
+		return (R) this;
+	}
+
+	/**
+	 * Adds an 'OR' part to the where-clause.
+	 * <p>
+	 * For example: .or("o.loggedIn=:loggedIn");
+	 *
+	 * @param orWhereClause the clause to add
+	 * @return an instance of this builder to provide a fluent interface
+	 */
+	@SuppressWarnings("unchecked")
+	public R or(final String orWhereClause) {
+		if (whereClause == null || whereClause.isBlank())
+			whereClause = orWhereClause;
+		else
+			whereClause += " OR " + orWhereClause;
+		return (R) this;
+	}
+
+	/**
+	 * Clears the where-clause and resets it to default.
+	 * <p>
+	 * Default is the empty string.
+	 *
+	 * @return an instance of this builder to provide a fluent interface
+	 */
+	public R clearWhere() {
+		return where(null);
+	}
+
+	/**
+	 * Clears the order-by-clause and resets it to default.
+	 * <p>
+	 * Default is the empty string.
+	 *
+	 * @return an instance of this builder to provide a fluent interface
+	 */
+	public R clearOrderBy() {
+		return orderBy(null);
+	}
+
+	/**
+	 * Clears the parameters and resets them to default.
+	 * <p>
+	 * Default is an empty map.
+	 *
+	 * @return an instance of this builder to provide a fluent interface
+	 */
+	public R clearParameters() {
+		return parameters(null);
+	}
+
+	/**
+	 * Set parameters used in all the clauses.
+	 * <p>
+	 * Default is an empty map.<br>
+	 * To reset it to default, set it to null.
+	 *
+	 * @param params the new {@link ParamMap}
+	 * @return an instance of this builder to provide a fluent interface
+	 */
+	@SuppressWarnings("unchecked")
+	public R parameters(final ParamMap params) {
+		parameters = params;
+		if (this.parameters == null)
+			parameters = ParamMap.builder().build();
+		return (R) this;
+	}
+
+	/**
+	 * Adds a single parameter that will be used in all the clauses.
+	 *
+	 * @param paramKey   the key of the parameter
+	 * @param paramValue the value of the parameter
+	 * @return an instance of this builder to provide a fluent interface
+	 */
+	@SuppressWarnings("unchecked")
+	public R addParam(final String paramKey, final Object paramValue) {
+		parameters.addParameter(paramKey, paramValue);
+		return (R) this;
+	}
+
+	/**
+	 * Sets a custom order-by-clause.
+	 * <p>
+	 * Default is "o.id ASC"<br>
+	 * To reset it to default, set it to null.<br>
+	 * To completely delete it, set it to an empty string.
+	 *
+	 * @param orderByClause the new clause
+	 * @return an instance of this builder to provide a fluent interface
+	 */
+	@SuppressWarnings("unchecked")
+	public R orderBy(final String orderByClause) {
+		this.orderByClause = orderByClause;
+		if (this.orderByClause == null)
+			this.orderByClause = "o.id ASC";
+		return (R) this;
+	}
+
+	/**
+	 * Adds an ASC-segment to the order-by-clause.
+	 *
+	 * @param field the name of the field ("o.id" or "o.createdOn" for example)
+	 * @return an instance of this builder to provide a fluent interface
+	 */
+	@SuppressWarnings("unchecked")
+	public R asc(final String field) {
+		if (orderByClause == null || orderByClause.isBlank())
+			orderByClause = field;
+		else
+			orderByClause = ", " + field;
+		orderByClause += " ASC";
+		return (R) this;
+	}
+
+	/**
+	 * Adds an DESC-segment to the order-by-clause.
+	 *
+	 * @param field the name of the field ("o.id" or "o.createdOn" for example)
+	 * @return an instance of this builder to provide a fluent interface
+	 */
+	@SuppressWarnings("unchecked")
+	public R desc(final String field) {
+		if (orderByClause == null || orderByClause.isBlank())
+			orderByClause = field;
+		else
+			orderByClause = ", " + field;
+		orderByClause += " DESC";
+		return (R) this;
+	}
+
+	/**
+	 * Sets this query to be locked pessimistically when being called, so that this
+	 * entityManager is the only one that can access this
+	 *
+	 * @return an instance of this builder to provide a fluent interface
+	 */
+	@SuppressWarnings("unchecked")
+	public R lockPessimistic() {
+		lockPessimistic = true;
+		return (R) this;
+	}
+}

src/main/java/info/unterrainer/commons/httpserver/daos/CountQueryBuilder.java

@@ -0,0 +1,21 @@
+package info.unterrainer.commons.httpserver.daos;
+
+import javax.persistence.EntityManagerFactory;
+import javax.persistence.Query;
+
+import info.unterrainer.commons.rdbutils.Transactions;
+import info.unterrainer.commons.rdbutils.entities.BasicJpa;
+
+public class CountQueryBuilder<P extends BasicJpa, T> extends BasicQueryBuilder<P, T, CountQueryBuilder<P, T>> {
+
+	CountQueryBuilder(final EntityManagerFactory emf, final JpqlDao<P> dao) {
+		super(emf, dao);
+	}
+
+	public Query build() {
+		if (entityManager != null)
+			return dao.getCountQuery(entityManager, selectClause, joinClause, whereClause, parameters);
+		return Transactions.withNewTransactionReturning(emf,
+				em -> dao.getCountQuery(em, selectClause, joinClause, whereClause, parameters));
+	}
+}