DATAJPA-920 - Add support for exists projection in repository query derivation.

pom.xml

@@ -5,7 +5,7 @@
 
 	<groupId>org.springframework.data</groupId>
 	<artifactId>spring-data-jpa</artifactId>
-	<version>1.11.0.BUILD-SNAPSHOT</version>
+	<version>1.11.0.DATAJPA-920-SNAPSHOT</version>
 
 	<name>Spring Data JPA</name>
 	<description>Spring Data module for JPA repositories.</description>
@@ -27,7 +27,7 @@
 		<hsqldb1>1.8.0.10</hsqldb1>
 		<jpa>2.0.0</jpa>
 		<openjpa>2.4.1</openjpa>
-		<springdata.commons>1.13.0.BUILD-SNAPSHOT</springdata.commons>
+		<springdata.commons>1.13.0.DATACMNS-875-SNAPSHOT</springdata.commons>
 
 		<sonar.dynamicAnalysis>reuseReports</sonar.dynamicAnalysis>
 

src/main/java/org/springframework/data/jpa/repository/query/JpaQueryCreator.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2008-2015 the original author or authors.
+ * Copyright 2008-2016 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -15,13 +15,15 @@
  */
 package org.springframework.data.jpa.repository.query;
 
+import static org.springframework.data.jpa.domain.AbstractPersistable_.*;
 import static org.springframework.data.jpa.repository.query.QueryUtils.*;
 import static org.springframework.data.repository.query.parser.Part.Type.*;
 
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Iterator;
 import java.util.List;
+import java.util.Set;
 
 import javax.persistence.criteria.CriteriaBuilder;
 import javax.persistence.criteria.CriteriaQuery;
@@ -30,6 +32,7 @@
 import javax.persistence.criteria.Predicate;
 import javax.persistence.criteria.Root;
 import javax.persistence.criteria.Selection;
+import javax.persistence.metamodel.SingularAttribute;
 
 import org.springframework.data.domain.Sort;
 import org.springframework.data.jpa.repository.query.ParameterMetadataProvider.ParameterMetadata;
@@ -45,6 +48,7 @@
  * Query creator to create a {@link CriteriaQuery} from a {@link PartTree}.
  * 
  * @author Oliver Gierke
+ * @author Mark Paluch
  */
 public class JpaQueryCreator extends AbstractQueryCreator<CriteriaQuery<? extends Object>, Predicate> {
 
@@ -53,6 +57,7 @@ public class JpaQueryCreator extends AbstractQueryCreator<CriteriaQuery<? extend
 	private final CriteriaQuery<? extends Object> query;
 	private final ParameterMetadataProvider provider;
 	private final ReturnedType returnedType;
+	private final PartTree tree;
 
 	/**
 	 * Create a new {@link JpaQueryCreator}.
@@ -66,6 +71,7 @@ public JpaQueryCreator(PartTree tree, ReturnedType type, CriteriaBuilder builder
 			ParameterMetadataProvider provider) {
 
 		super(tree);
+		this.tree = tree;
 
 		CriteriaQuery<? extends Object> criteriaQuery = createCriteriaQuery(builder, type);
 
@@ -87,7 +93,7 @@ protected CriteriaQuery<? extends Object> createCriteriaQuery(CriteriaBuilder bu
 
 		Class<?> typeToRead = type.getTypeToRead();
 
-		return typeToRead == null ? builder.createTupleQuery() : builder.createQuery(typeToRead);
+		return (typeToRead == null || tree.isExistsProjection()) ? builder.createTupleQuery() : builder.createQuery(typeToRead);
 	}
 
 	/**
@@ -160,6 +166,24 @@ protected CriteriaQuery<? extends Object> complete(Predicate predicate, Sort sor
 			}
 
 			query = query.multiselect(selections);
+		} else if (tree.isExistsProjection()) {
+
+			if (root.getModel().hasSingleIdAttribute()) {
+
+				SingularAttribute<?, ?> id = root.getModel().getId(root.getModel().getIdType().getJavaType());
+				query = query.multiselect(root.get((SingularAttribute) id).alias(id.getName()));
+			} else {
+
+				List<Selection<?>> selections = new ArrayList<Selection<?>>();
+
+				Set<SingularAttribute<?, ?>> idClassAttributes = (Set<SingularAttribute<?, ?>>) root.getModel().getIdClassAttributes();
+
+				for (SingularAttribute<?, ?> attribute : idClassAttributes) {
+					selections.add(root.get((SingularAttribute) attribute).alias(attribute.getName()));
+				}
+				selections.add(root.get((SingularAttribute) id).alias(id.getName()));
+				query = query.multiselect(selections);
+			}
 		} else {
 			query = query.select((Root) root);
 		}
@@ -170,7 +194,7 @@ protected CriteriaQuery<? extends Object> complete(Predicate predicate, Sort sor
 
 	/**
 	 * Creates a {@link Predicate} from the given {@link Part}.
-	 * 
+	 *
 	 * @param part
 	 * @param root
 	 * @param iterator

src/main/java/org/springframework/data/jpa/repository/query/JpaQueryExecution.java

@@ -272,6 +272,20 @@ protected Object doExecute(AbstractJpaQuery jpaQuery, Object[] values) {
 		}
 	}
 
+	/**
+	 * {@link Execution} performing an exists check on the query.
+	 *
+	 * @author Mark Paluch
+	 * @since 1.11
+	 */
+	static class ExistsExecution extends JpaQueryExecution {
+
+		@Override
+		protected Object doExecute(AbstractJpaQuery query, Object[] values) {
+			return !query.createQuery(values).getResultList().isEmpty();
+		}
+	}
+
 	/**
 	 * {@link Execution} executing a stored procedure.
 	 * 

src/main/java/org/springframework/data/jpa/repository/query/PartTreeJpaQuery.java

@@ -26,6 +26,7 @@
 import org.springframework.data.domain.Sort;
 import org.springframework.data.jpa.provider.PersistenceProvider;
 import org.springframework.data.jpa.repository.query.JpaQueryExecution.DeleteExecution;
+import org.springframework.data.jpa.repository.query.JpaQueryExecution.ExistsExecution;
 import org.springframework.data.jpa.repository.query.ParameterMetadataProvider.ParameterMetadata;
 import org.springframework.data.repository.query.ParametersParameterAccessor;
 import org.springframework.data.repository.query.ResultProcessor;
@@ -94,7 +95,14 @@ public TypedQuery<Long> doCreateCountQuery(Object[] values) {
 	 */
 	@Override
 	protected JpaQueryExecution getExecution() {
-		return this.tree.isDelete() ? new DeleteExecution(em) : super.getExecution();
+
+		if(this.tree.isDelete()) {
+			return new DeleteExecution(em);
+		} else if(this.tree.isExistsProjection()) {
+			return new ExistsExecution();
+		}
+
+		return super.getExecution();
 	}
 
 	/**
@@ -168,6 +176,10 @@ private Query restrictMaxResultsIfNecessary(Query query) {
 				query.setMaxResults(tree.getMaxResults());
 			}
 
+			if(tree.isExistsProjection()) {
+				query.setMaxResults(1);
+			}
+
 			return query;
 		}
 

src/test/java/org/springframework/data/jpa/domain/sample/EmbeddedIdExampleEmployee.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2013-2104 the original author or authors.
+ * Copyright 2013-2016 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -23,6 +23,7 @@
 
 /**
  * @author Thomas Darimont
+ * @author Mark Paluch
  */
 @Entity
 public class EmbeddedIdExampleEmployee {
@@ -33,6 +34,8 @@ public class EmbeddedIdExampleEmployee {
 	@ManyToOne(cascade = CascadeType.ALL)//
 	EmbeddedIdExampleDepartment department;
 
+	String name;
+
 	public EmbeddedIdExampleEmployeePK getEmployeePk() {
 		return employeePk;
 	}
@@ -48,4 +51,12 @@ public EmbeddedIdExampleDepartment getDepartment() {
 	public void setDepartment(EmbeddedIdExampleDepartment department) {
 		this.department = department;
 	}
+
+	public String getName() {
+		return name;
+	}
+
+	public void setName(String name) {
+		this.name = name;
+	}
 }

src/test/java/org/springframework/data/jpa/domain/sample/IdClassExampleDepartment.java

@@ -18,6 +18,9 @@
 import javax.persistence.Entity;
 import javax.persistence.Id;
 
+/**
+ * @author Thomas Darimont
+ */
 @Entity
 public class IdClassExampleDepartment {
 

src/test/java/org/springframework/data/jpa/domain/sample/IdClassExampleEmployee.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2013 the original author or authors.
+ * Copyright 2013-2016 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -20,13 +20,19 @@
 import javax.persistence.IdClass;
 import javax.persistence.ManyToOne;
 
+/**
+ * @author Thomas Darimont
+ * @author Mark Paluch
+ */
 @IdClass(IdClassExampleEmployeePK.class)
 @Entity
 public class IdClassExampleEmployee {
 
 	@Id long empId;
 	@Id @ManyToOne IdClassExampleDepartment department;
 
+	String name;
+
 	public long getEmpId() {
 		return empId;
 	}
@@ -42,4 +48,12 @@ public IdClassExampleDepartment getDepartment() {
 	public void setDepartment(IdClassExampleDepartment department) {
 		this.department = department;
 	}
+
+	public String getName() {
+		return name;
+	}
+
+	public void setName(String name) {
+		this.name = name;
+	}
 }

src/test/java/org/springframework/data/jpa/repository/RepositoryWithCompositeKeyTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2013-2014 the original author or authors.
+ * Copyright 2013-2016 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -46,8 +46,9 @@
 
 /**
  * Tests some usage variants of composite keys with spring data jpa.
- * 
+ *
  * @author Thomas Darimont
+ * @author Mark Paluch
  */
 @RunWith(SpringJUnit4ClassRunner.class)
 @ContextConfiguration(classes = SampleConfig.class)
@@ -301,4 +302,49 @@ public void shouldAllowFindAllWithIdsForEntitiesWithCompoundIdClassKeys() {
 
 		assertThat(result, hasSize(2));
 	}
+
+	/**
+	 * @see DATAJPA-920
+	 */
+	@Test
+	public void shouldExecuteExistsQueryForEntitiesWithEmbeddedId() {
+
+		EmbeddedIdExampleDepartment dep1 = new EmbeddedIdExampleDepartment();
+		dep1.setDepartmentId(1L);
+		dep1.setName("Dep1");
+
+		EmbeddedIdExampleEmployeePK key = new EmbeddedIdExampleEmployeePK();
+		key.setDepartmentId(1L);
+		key.setEmployeeId(1L);
+
+		EmbeddedIdExampleEmployee emp = new EmbeddedIdExampleEmployee();
+		emp.setDepartment(dep1);
+		emp.setEmployeePk(key);
+		emp.setName("White");
+
+		employeeRepositoryWithEmbeddedId.save(emp);
+
+		assertThat(employeeRepositoryWithEmbeddedId.existsByName(emp.getName()), is(true));
+	}
+
+	/**
+	 * @see DATAJPA-920
+	 */
+	@Test
+	public void shouldExecuteExistsQueryForEntitiesWithCompoundIdClassKeys() {
+
+		IdClassExampleDepartment dep2 = new IdClassExampleDepartment();
+		dep2.setDepartmentId(2L);
+		dep2.setName("Dep2");
+
+		IdClassExampleEmployee emp1 = new IdClassExampleEmployee();
+		emp1.setEmpId(3L);
+		emp1.setDepartment(dep2);
+		emp1.setName("White");
+
+		employeeRepositoryWithIdClass.save(emp1);
+
+		assertThat(employeeRepositoryWithIdClass.existsByName(emp1.getName()), is(true));
+		assertThat(employeeRepositoryWithIdClass.existsByName("Walter"), is(false));
+	}
 }

src/test/java/org/springframework/data/jpa/repository/UserRepositoryTests.java

@@ -1096,6 +1096,18 @@ public void executesDerivedCountQueryToInt() {
 		assertThat(repository.countUsersByFirstname("Dave"), is(1));
 	}
 
+	/**
+	 * @see DATAJPA-231
+	 */
+	@Test
+	public void executesDerivedExistsQuery() {
+
+		flushTestUsers();
+
+		assertThat(repository.existsByLastname("Matthews"), is(true));
+		assertThat(repository.existsByLastname("Hans Peter"), is(false));
+	}
+
 	/**
 	 * @see DATAJPA-332
 	 */

src/test/java/org/springframework/data/jpa/repository/query/PartTreeJpaQueryIntegrationTests.java

@@ -56,6 +56,7 @@
  * Integration tests for {@link PartTreeJpaQuery}.
  * 
  * @author Oliver Gierke
+ * @author Mark Paluch
  */
 @RunWith(SpringJUnit4ClassRunner.class)
 @ContextConfiguration("classpath:infrastructure.xml")
@@ -120,6 +121,34 @@ public void recreatesQueryIfNullValueIsGiven() throws Exception {
 		assertThat(HibernateUtils.getHibernateQuery(getValue(query, PROPERTY)), endsWith("firstname is null"));
 	}
 
+	/**
+	 * @see DATAJPA-920
+	 */
+	@Test
+	public void shouldLimitExistsProjectionQueries() throws Exception {
+
+		JpaQueryMethod queryMethod = getQueryMethod("existsByFirstname", String.class);
+		PartTreeJpaQuery jpaQuery = new PartTreeJpaQuery(queryMethod, entityManager, provider);
+
+		Query query = jpaQuery.createQuery(new Object[]{"Matthews"});
+
+		assertThat(query.getMaxResults(), is(1));
+	}
+
+	/**
+	 * @see DATAJPA-920
+	 */
+	@Test
+	public void shouldSelectAliasedIdForExistsProjectionQueries() throws Exception {
+
+		JpaQueryMethod queryMethod = getQueryMethod("existsByFirstname", String.class);
+		PartTreeJpaQuery jpaQuery = new PartTreeJpaQuery(queryMethod, entityManager, provider);
+
+		Query query = jpaQuery.createQuery(new Object[]{"Matthews"});
+
+		assertThat(HibernateUtils.getHibernateQuery(getValue(query, PROPERTY)), containsString(".id from User as"));
+	}
+
 	private void testIgnoreCase(String methodName, Object... values) throws Exception {
 
 		Class<?>[] parameterTypes = new Class[values.length];
@@ -173,6 +202,8 @@ interface UserRepository extends Repository<User, Long> {
 
 		User findByIdAllIgnoringCase(Integer id);
 
+		boolean existsByFirstname(String firstname);
+
 		List<User> findByCreatedAtAfter(@Temporal(TemporalType.TIMESTAMP) @Param("refDate") Date refDate);
 	}
 }