Add fluent API support for QuerydslKeyValueRepository.

Also reuse ProjectionFactory from repository factory.

Closes #397.

Author: mp911de

src/main/java/org/springframework/data/keyvalue/repository/support/DtoInstantiatingConverter.java

@@ -0,0 +1,102 @@
+/*
+ * Copyright 2021 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.
+ * You may obtain a copy of the License at
+ *
+ *      https://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.
+ */
+package org.springframework.data.keyvalue.repository.support;
+
+import org.springframework.core.convert.converter.Converter;
+import org.springframework.data.mapping.PersistentEntity;
+import org.springframework.data.mapping.PersistentProperty;
+import org.springframework.data.mapping.PersistentPropertyAccessor;
+import org.springframework.data.mapping.PreferredConstructor;
+import org.springframework.data.mapping.PreferredConstructor.Parameter;
+import org.springframework.data.mapping.SimplePropertyHandler;
+import org.springframework.data.mapping.context.MappingContext;
+import org.springframework.data.mapping.model.EntityInstantiator;
+import org.springframework.data.mapping.model.EntityInstantiators;
+import org.springframework.data.mapping.model.ParameterValueProvider;
+import org.springframework.util.Assert;
+
+/**
+ * {@link Converter} to instantiate DTOs from fully equipped domain objects.
+ *
+ * @author Mark Paluch
+ * @since 2.6
+ */
+class DtoInstantiatingConverter implements Converter<Object, Object> {
+
+	private final Class<?> targetType;
+	private final MappingContext<? extends PersistentEntity<?, ?>, ? extends PersistentProperty<?>> context;
+	private final EntityInstantiator instantiator;
+
+	/**
+	 * Creates a new {@link Converter} to instantiate DTOs.
+	 *
+	 * @param dtoType must not be {@literal null}.
+	 * @param context must not be {@literal null}.
+	 * @param entityInstantiators must not be {@literal null}.
+	 */
+	public DtoInstantiatingConverter(Class<?> dtoType,
+			MappingContext<? extends PersistentEntity<?, ?>, ? extends PersistentProperty<?>> context,
+			EntityInstantiators entityInstantiators) {
+
+		Assert.notNull(dtoType, "DTO type must not be null!");
+		Assert.notNull(context, "MappingContext must not be null!");
+		Assert.notNull(entityInstantiators, "EntityInstantiators must not be null!");
+
+		this.targetType = dtoType;
+		this.context = context;
+		this.instantiator = entityInstantiators.getInstantiatorFor(context.getRequiredPersistentEntity(dtoType));
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.core.convert.converter.Converter#convert(java.lang.Object)
+	 */
+	@Override
+	@SuppressWarnings({ "rawtypes", "unchecked" })
+	public Object convert(Object source) {
+
+		if (targetType.isInterface()) {
+			return source;
+		}
+
+		PersistentEntity<?, ?> sourceEntity = context.getRequiredPersistentEntity(source.getClass());
+		PersistentPropertyAccessor<?> sourceAccessor = sourceEntity.getPropertyAccessor(source);
+		PersistentEntity<?, ?> targetEntity = context.getRequiredPersistentEntity(targetType);
+		PreferredConstructor<?, ? extends PersistentProperty<?>> constructor = targetEntity.getPersistenceConstructor();
+
+		Object dto = instantiator.createInstance(targetEntity, new ParameterValueProvider() {
+
+			@Override
+			public Object getParameterValue(Parameter parameter) {
+				return sourceAccessor.getProperty(sourceEntity.getPersistentProperty(parameter.getName()));
+			}
+		});
+
+		PersistentPropertyAccessor<?> dtoAccessor = targetEntity.getPropertyAccessor(dto);
+
+		targetEntity.doWithProperties((SimplePropertyHandler) property -> {
+
+			if (constructor.isConstructorParameter(property)) {
+				return;
+			}
+
+			dtoAccessor.setProperty(property,
+					sourceAccessor.getProperty(sourceEntity.getPersistentProperty(property.getName())));
+		});
+
+		return dto;
+	}
+}

src/main/java/org/springframework/data/keyvalue/repository/support/KeyValueRepositoryFactory.java

@@ -31,6 +31,7 @@
 import org.springframework.data.mapping.context.MappingContext;
 import org.springframework.data.projection.ProjectionFactory;
 import org.springframework.data.querydsl.QuerydslPredicateExecutor;
+import org.springframework.data.querydsl.SimpleEntityPathResolver;
 import org.springframework.data.repository.core.EntityInformation;
 import org.springframework.data.repository.core.NamedQueries;
 import org.springframework.data.repository.core.RepositoryInformation;
@@ -152,12 +153,12 @@ protected RepositoryFragments getRepositoryFragments(RepositoryMetadata metadata
 
 	/**
 	 * Creates {@link RepositoryFragments} based on {@link RepositoryMetadata} to add Key-Value-specific extensions.
-	 * Typically adds a {@link QuerydslMongoPredicateExecutor} if the repository interface uses Querydsl.
+	 * Typically adds a {@link QuerydslKeyValuePredicateExecutor} if the repository interface uses Querydsl.
 	 * <p>
 	 * Can be overridden by subclasses to customize {@link RepositoryFragments}.
 	 *
 	 * @param metadata repository metadata.
-	 * @param operations the MongoDB operations manager.
+	 * @param operations the KeyValue operations manager.
 	 * @return
 	 * @since 2.6
 	 */
@@ -171,7 +172,8 @@ protected RepositoryFragments getRepositoryFragments(RepositoryMetadata metadata
 			}
 
 			return RepositoryFragments
-					.just(new QuerydslKeyValuePredicateExecutor<>(getEntityInformation(metadata.getDomainType()), operations));
+					.just(new QuerydslKeyValuePredicateExecutor<>(getEntityInformation(metadata.getDomainType()),
+							getProjectionFactory(), operations, SimpleEntityPathResolver.INSTANCE));
 		}
 
 		return RepositoryFragments.empty();