DATAMONGO-347 - Derived repository queries now correctly resolve referenced DBRef properties.

Added toDBRef(…) method to MongoWriter to be able to create a DBRef representation of an object. Polished DBRef creation implementation inside MappingMongoConverter. Removed collection and id attributes from @DBREF annotation as they have neither been documented nor used so far. Refactored MongoQueryCreator to be aware of the property and convert the given value into a DBRef if necessary.

Author: odrotbohm

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/convert/MappingMongoConverter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2011 by the original author(s).
+ * Copyright 2011-2012 by the original author(s).
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -265,6 +265,22 @@ public void doWithAssociation(Association<MongoPersistentProperty> association)
 		return result;
 	}
 
+	/* 
+	 * (non-Javadoc)
+	 * @see org.springframework.data.mongodb.core.convert.MongoWriter#toDBRef(java.lang.Object, org.springframework.data.mongodb.core.mapping.MongoPersistentProperty)
+	 */
+	public DBRef toDBRef(Object object, MongoPersistentProperty referingProperty) {
+
+		org.springframework.data.mongodb.core.mapping.DBRef annotation = null;
+
+		if (referingProperty != null) {
+			annotation = referingProperty.getDBRef();
+			Assert.isTrue(annotation != null, "The referenced property has to be mapped with @DBRef!");
+		}
+
+		return createDBRef(object, annotation);
+	}
+
 	/**
 	 * Root entry method into write conversion. Adds a type discriminator to the {@link DBObject}. Shouldn't be called for
 	 * nested conversions.
@@ -658,28 +674,31 @@ private Object getPotentiallyConvertedSimpleRead(Object value, Class<?> target)
 
 	protected DBRef createDBRef(Object target, org.springframework.data.mongodb.core.mapping.DBRef dbref) {
 
+		Assert.notNull(target);
+
 		MongoPersistentEntity<?> targetEntity = mappingContext.getPersistentEntity(target.getClass());
-		if (null == targetEntity || null == targetEntity.getIdProperty()) {
-			return null;
+
+		if (null == targetEntity) {
+			throw new MappingException("No mapping metadata found for " + target.getClass());
 		}
 
 		MongoPersistentProperty idProperty = targetEntity.getIdProperty();
+
+		if (idProperty == null) {
+			throw new MappingException("No id property found on class " + targetEntity.getType());
+		}
+
 		BeanWrapper<MongoPersistentEntity<Object>, Object> wrapper = BeanWrapper.create(target, conversionService);
 		Object id = wrapper.getProperty(idProperty, Object.class, useFieldAccessOnly);
 
 		if (null == id) {
 			throw new MappingException("Cannot create a reference to an object with a NULL id.");
 		}
 
-		String collection = dbref.collection();
-		if ("".equals(collection)) {
-			collection = targetEntity.getCollection();
-		}
-
-		String dbname = dbref.db();
-		DB db = StringUtils.hasText(dbname) ? mongoDbFactory.getDb(dbname) : mongoDbFactory.getDb();
+		DB db = mongoDbFactory.getDb();
+		db = dbref != null && StringUtils.hasText(dbref.db()) ? mongoDbFactory.getDb(dbref.db()) : db;
 
-		return new DBRef(db, collection, idMapper.convertId(id));
+		return new DBRef(db, targetEntity.getCollection(), idMapper.convertId(id));
 	}
 
 	protected Object getValueInternal(MongoPersistentProperty prop, DBObject dbo, SpELExpressionEvaluator eval,

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/convert/MongoWriter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2010-2011 the original author or authors.
+ * Copyright 2010-2012 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.
@@ -16,8 +16,10 @@
 package org.springframework.data.mongodb.core.convert;
 
 import org.springframework.data.convert.EntityWriter;
+import org.springframework.data.mongodb.core.mapping.MongoPersistentProperty;
 
 import com.mongodb.DBObject;
+import com.mongodb.DBRef;
 
 /**
  * A MongoWriter is responsible for converting an object of type T to the native MongoDB representation DBObject.
@@ -37,4 +39,14 @@ public interface MongoWriter<T> extends EntityWriter<T, DBObject> {
 	 * @return
 	 */
 	Object convertToMongoType(Object obj);
+
+	/**
+	 * Creates a {@link DBRef} to refer to the given object.
+	 * 
+	 * @param object the object to create a {@link DBRef} to link to. The object's type has to carry an id attribute.
+	 * @param referingProperty the client-side property referring to the object which might carry additional metadata for
+	 *          the {@link DBRef} object to create. Can be {@literal null}.
+	 * @return will never be {@literal null}.
+	 */
+	DBRef toDBRef(Object object, MongoPersistentProperty referingProperty);
 }

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/mapping/DBRef.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2011 by the original author(s).
+ * Copyright 2011-2012 by the original author(s).
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -13,9 +13,9 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-
 package org.springframework.data.mongodb.core.mapping;
 
+import java.lang.annotation.Documented;
 import java.lang.annotation.ElementType;
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
@@ -24,19 +24,21 @@
 import org.springframework.data.annotation.Reference;
 
 /**
- * An annotation that indicates the annotated field is to be stored using a com.mongodb.DBRef
+ * An annotation that indicates the annotated field is to be stored using a {@link com.mongodb.DBRef}.
  * 
- * @author Jon Brisbin <jbrisbin@vmware.com>
+ * @author Jon Brisbin
+ * @authot Oliver Gierke
  */
+@Documented
 @Retention(RetentionPolicy.RUNTIME)
 @Target({ ElementType.FIELD })
 @Reference
 public @interface DBRef {
 
-	String collection() default "";
-
-	String id() default "";
-
+	/**
+	 * The database the referred entity resides in.
+	 * 
+	 * @return
+	 */
 	String db() default "";
-
 }

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/repository/query/ConvertingParameterAccessor.java

@@ -22,6 +22,7 @@
 import org.springframework.data.mongodb.core.convert.MongoWriter;
 import org.springframework.data.mongodb.core.geo.Distance;
 import org.springframework.data.mongodb.core.geo.Point;
+import org.springframework.data.mongodb.core.mapping.MongoPersistentProperty;
 import org.springframework.data.repository.query.ParameterAccessor;
 import org.springframework.util.Assert;
 
@@ -137,37 +138,33 @@ public ConvertingIterator(Iterator<Object> delegate) {
 		}
 
 		/*
-		   * (non-Javadoc)
-		   *
-		   * @see java.util.Iterator#hasNext()
-		   */
+		 * (non-Javadoc)
+		 * @see java.util.Iterator#hasNext()
+		 */
 		public boolean hasNext() {
 			return delegate.hasNext();
 		}
 
 		/*
-		   * (non-Javadoc)
-		   *
-		   * @see java.util.Iterator#next()
-		   */
+		 * (non-Javadoc)
+		 * @see java.util.Iterator#next()
+		 */
 		public Object next() {
-
 			return delegate.next();
 		}
 
-		/* (non-Javadoc)
+		/* 
+		 * (non-Javadoc)
 		 * @see org.springframework.data.mongodb.repository.ConvertingParameterAccessor.PotentiallConvertingIterator#nextConverted()
 		 */
-		public Object nextConverted() {
-
-			return getConvertedValue(next());
+		public Object nextConverted(MongoPersistentProperty property) {
+			return property.isAssociation() ? writer.toDBRef(next(), property) : getConvertedValue(next());
 		}
 
 		/*
-		   * (non-Javadoc)
-		   *
-		   * @see java.util.Iterator#remove()
-		   */
+		 * (non-Javadoc)
+		 * @see java.util.Iterator#remove()
+		 */
 		public void remove() {
 			delegate.remove();
 		}
@@ -185,6 +182,6 @@ public interface PotentiallyConvertingIterator extends Iterator<Object> {
 		 * 
 		 * @return
 		 */
-		Object nextConverted();
+		Object nextConverted(MongoPersistentProperty property);
 	}
 }

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/repository/query/MongoQueryCreator.java

@@ -98,7 +98,8 @@ protected Criteria create(Part part, Iterator<Object> iterator) {
 		}
 
 		PersistentPropertyPath<MongoPersistentProperty> path = context.getPersistentPropertyPath(part.getProperty());
-		Criteria criteria = from(part.getType(),
+		MongoPersistentProperty property = path.getLeafProperty();
+		Criteria criteria = from(part.getType(), property,
 				where(path.toDotPath(MongoPersistentProperty.PropertyToFieldNameConverter.INSTANCE)),
 				(PotentiallyConvertingIterator) iterator);
 
@@ -116,10 +117,11 @@ protected Criteria and(Part part, Criteria base, Iterator<Object> iterator) {
 			return create(part, iterator);
 		}
 
-		PersistentPropertyPath<MongoPersistentProperty> path2 = context.getPersistentPropertyPath(part.getProperty());
+		PersistentPropertyPath<MongoPersistentProperty> path = context.getPersistentPropertyPath(part.getProperty());
+		MongoPersistentProperty property = path.getLeafProperty();
 
-		Criteria criteria = from(part.getType(),
-				where(path2.toDotPath(MongoPersistentProperty.PropertyToFieldNameConverter.INSTANCE)),
+		Criteria criteria = from(part.getType(), property,
+				where(path.toDotPath(MongoPersistentProperty.PropertyToFieldNameConverter.INSTANCE)),
 				(PotentiallyConvertingIterator) iterator);
 
 		return criteria.andOperator(criteria);
@@ -164,34 +166,36 @@ protected Query complete(Criteria criteria, Sort sort) {
 	}
 
 	/**
-	 * Populates the given {@link CriteriaDefinition} depending on the {@link Type} given.
+	 * Populates the given {@link CriteriaDefinition} depending on the {@link Part} given.
 	 * 
-	 * @param type
+	 * @param part
+	 * @param property
 	 * @param criteria
 	 * @param parameters
 	 * @return
 	 */
-	private Criteria from(Type type, Criteria criteria, PotentiallyConvertingIterator parameters) {
+	private Criteria from(Type type, MongoPersistentProperty property, Criteria criteria,
+			PotentiallyConvertingIterator parameters) {
 
 		switch (type) {
 		case GREATER_THAN:
-			return criteria.gt(parameters.nextConverted());
+			return criteria.gt(parameters.nextConverted(property));
 		case GREATER_THAN_EQUAL:
-			return criteria.gte(parameters.nextConverted());
+			return criteria.gte(parameters.nextConverted(property));
 		case LESS_THAN:
-			return criteria.lt(parameters.nextConverted());
+			return criteria.lt(parameters.nextConverted(property));
 		case LESS_THAN_EQUAL:
-			return criteria.lte(parameters.nextConverted());
+			return criteria.lte(parameters.nextConverted(property));
 		case BETWEEN:
-			return criteria.gt(parameters.nextConverted()).lt(parameters.nextConverted());
+			return criteria.gt(parameters.nextConverted(property)).lt(parameters.nextConverted(property));
 		case IS_NOT_NULL:
 			return criteria.ne(null);
 		case IS_NULL:
 			return criteria.is(null);
 		case NOT_IN:
-			return criteria.nin(nextAsArray(parameters));
+			return criteria.nin(nextAsArray(parameters, property));
 		case IN:
-			return criteria.in(nextAsArray(parameters));
+			return criteria.in(nextAsArray(parameters, property));
 		case LIKE:
 			String value = parameters.next().toString();
 			return criteria.regex(toLikeRegex(value));
@@ -225,9 +229,9 @@ private Criteria from(Type type, Criteria criteria, PotentiallyConvertingIterato
 			Object parameter = parameters.next();
 			return criteria.within((Shape) parameter);
 		case SIMPLE_PROPERTY:
-			return criteria.is(parameters.nextConverted());
+			return criteria.is(parameters.nextConverted(property));
 		case NEGATING_SIMPLE_PROPERTY:
-			return criteria.not().is(parameters.nextConverted());
+			return criteria.not().is(parameters.nextConverted(property));
 		}
 
 		throw new IllegalArgumentException("Unsupported keyword!");
@@ -253,8 +257,8 @@ private <T> T nextAs(Iterator<Object> iterator, Class<T> type) {
 				parameter.getClass()));
 	}
 
-	private Object[] nextAsArray(PotentiallyConvertingIterator iterator) {
-		Object next = iterator.nextConverted();
+	private Object[] nextAsArray(PotentiallyConvertingIterator iterator, MongoPersistentProperty property) {
+		Object next = iterator.nextConverted(property);
 
 		if (next instanceof Collection) {
 			return ((Collection<?>) next).toArray();

spring-data-mongodb/src/test/java/org/springframework/data/mongodb/core/MongoOperationsUnitTests.java

@@ -37,6 +37,7 @@
 
 import com.mongodb.BasicDBObject;
 import com.mongodb.DBObject;
+import com.mongodb.DBRef;
 
 /**
  * Abstract base class for unit tests to specify behaviour we expect from {@link MongoOperations}. Subclasses return
@@ -80,6 +81,10 @@ public MappingContext<? extends MongoPersistentEntity<?>, MongoPersistentPropert
 			public Object convertToMongoType(Object obj) {
 				return null;
 			}
+
+			public DBRef toDBRef(Object object, MongoPersistentProperty referingProperty) {
+				return null;
+			}
 		};
 	}