package org.springframework.data.jpa.repository.support;
import java.util.Collections;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Optional;
import javax.persistence.EntityManager;
import org.springframework.data.jpa.repository.EntityGraph;
import org.springframework.data.jpa.repository.query.Jpa21Utils;
import org.springframework.data.jpa.repository.query.JpaEntityGraph;
import org.springframework.data.util.Optionals;
import org.springframework.util.Assert;
/**
* Default implementation of {@link QueryHints}.
*
* @author Christoph Strobl
* @author Oliver Gierke
* @since 2.0
*/
class DefaultQueryHints implements QueryHints {
private final JpaEntityInformation<?, ?> information;
private final CrudMethodMetadata metadata;
private final Optional<EntityManager> entityManager;
/**
* Creates a new {@link DefaultQueryHints} instance for the given {@link JpaEntityInformation},
* {@link CrudMethodMetadata}, {@link EntityManager} and whether to include fetch graphs.
*
* @param information must not be {@literal null}.
* @param metadata must not be {@literal null}.
* @param entityManager must not be {@literal null}.
* @param includeFetchGraphs
*/
private DefaultQueryHints(JpaEntityInformation<?, ?> information, CrudMethodMetadata metadata,
Optional<EntityManager> entityManager) {
this.information = information;
this.metadata = metadata;
this.entityManager = entityManager;
}
/**
* Creates a new {@link QueryHints} instance for the given {@link JpaEntityInformation}, {@link CrudMethodMetadata}
* and {@link EntityManager}.
*
* @param information must not be {@literal null}.
* @param metadata must not be {@literal null}.
* @param entityManager must not be {@literal null}.
* @return
*/
public static QueryHints of(JpaEntityInformation<?, ?> information, CrudMethodMetadata metadata) {
Assert.notNull(information, "JpaEntityInformation must not be null!");
Assert.notNull(metadata, "CrudMethodMetadata must not be null!");
return new DefaultQueryHints(information, metadata, Optional.empty());
}
/*
* (non-Javadoc)
* @see org.springframework.data.jpa.repository.support.QueryHints#withFetchGraphs()
*/
@Override
public QueryHints withFetchGraphs(EntityManager em) {
return new DefaultQueryHints(this.information, this.metadata, Optional.of(em));
}
/*
* (non-Javadoc)
* @see java.lang.Iterable#iterator()
*/
@Override
public Iterator<Entry<String, Object>> iterator() {
return asMap().entrySet().iterator();
}
/*
* (non-Javadoc)
* @see org.springframework.data.jpa.repository.support.QueryHints#asMap()
*/
@Override
public Map<String, Object> asMap() {
Map<String, Object> hints = new HashMap<>();
hints.putAll(metadata.getQueryHints());
hints.putAll(getFetchGraphs());
return hints;
}
private Map<String, Object> getFetchGraphs() {
return Optionals
.mapIfAllPresent(entityManager, metadata.getEntityGraph(),
(em, graph) -> Jpa21Utils.tryGetFetchGraphHints(em, getEntityGraph(graph), information.getJavaType()))
.orElse(Collections.emptyMap());
}
private JpaEntityGraph getEntityGraph(EntityGraph entityGraph) {
String fallbackName = information.getEntityName() + "." + metadata.getMethod().getName();
return new JpaEntityGraph(entityGraph, fallbackName);
}
}