Hi,

its a bug in SDN, I fixed it here, in case you want to patch locally.

https://github.com/spring-projects/spring-data-neo4j/blob/master/spring-data-neo4j/src/main/java/org/springframework/data/neo4j/support/conversion/ResultColumnValueExtractor.java#L75

        if (returnType.isCollectionLike()) {
             QueryResultBuilder qrb = new 
QueryResultBuilder((Iterable)columnValue, converter);
             return 
qrb.to(returnType.getActualType().getType()).as(returnType.getType());
        } else
           return converter.convert(columnValue, returnType.getType(), 
mappingPolicy);
    }

It will be part of the next release, thanks again for reporting it.

Cheers

Michael

Am 09.01.2014 um 09:13 schrieb Gwendal Mousset <[email protected]>:

> A precision i missed, the exception is not thrown when i execute the request 
> but when i try accessing to Iterable<CategoryDAO> getSubCategories().
> 
> 
> On Wednesday, January 8, 2014 1:47:18 PM UTC+1, Gwendal Mousset wrote:
> Hello,
> 
> I have an issue with cypher request using collect() function.
> I'm using spring-data-neo4j 3.0.0-M1 and Neo4j 2.0.0-M06.
> 
> In my data model i have Category nodes.
> Each category can have subcategories. 
> I want to retrieve the top categories list with the associated subcategories.
> 
>  Categ3 -- IS_SUBCATEGORY_OF --> Categ1 <-- IS_SUBCATEGORY_OF -- Categ2
> 
> My request:
> 
> MATCH (cat:Category) 
> WITH cat 
> MATCH (cat)<-[?:IS_SUBCATEGORY_OF]-(subCat:Category) 
> WHERE NOT cat-[:IS_SUBCATEGORY_OF]->() 
> RETURN cat as category, collect(subCat) as subCategories
> 
> 
> The query result is exactly what i expect in the console:
> 
> +--------------------------------------------------------------------------------------------------------------------------------------------------------+
> | category                                         | subCategories            
>                                                                            |
> +--------------------------------------------------------------------------------------------------------------------------------------------------------+
> | Node[128]{id:"e9c27555f46c4acdb29c8d0e89814467"} | []                       
>                                                                            |
> | Node[176]{id:"78f7c907068c4e1abd018fe560c2c03a"} | []                       
>                                                                            |
> | Node[134]{id:"e362b9c05a8f41f0aee877f914f2658f"} | []                       
>                                                                            |
> | Node[136]{id:"7b3d58a89ebd4010964004d58e962526"} | []                       
>                                                                            |
> | Node[118]{id:"3378af0b1f54405fb7ab2970cba5bff3"} | 
> [Node[34]{id:"d10cc4418c914c1281f7183da8109a4f"},Node[46]{id:"b3012831db924c22829a0335df2e90d1"}]
>    |
> | Node[130]{id:"e3e290b4d2c648b3a6a7d0fe8da461ef"} | []                       
>                                                                            |
> | Node[138]{id:"eb828c120cb248c2a5baa92734e39b91"} | []                       
>                                                                            |
> | Node[132]{id:"057aeb6913474454a329571b9a266305"} | []                       
>                                                                            |
> | Node[126]{id:"2671039fa6f24f5b806df682c238d1c4"} | 
> [Node[120]{id:"48bc7f2b34db49bfb40936864a7a4a80"},Node[122]{id:"373d94527286482fb8c807aee90d7f5e"}]
>  |
> +--------------------------------------------------------------------------------------------------------------------------------------------------------+
> 
> 
> My QueryResult interface:
> 
> @QueryResult
> public interface CategoryWithSubCategories {
> 
> 
>   /**
>    * 
>    * @return    A category.
>    */
>   @ResultColumn("category")
>   CategoryDAO getCategory();
>   
>   /**
>    * 
>    * @return    The subcategories.
>    */
>   @ResultColumn("subCategories")
>   Iterable<CategoryDAO> getSubCategories();
> }
> 
> My Query: 
> 
>  @Query("MATCH (cat:Category) " 
>       + "WITH cat " 
>       + "MATCH (cat)<-[?:IS_SUBCATEGORY_OF]-(subCat:Category) " 
>       + "WHERE NOT cat-[:IS_SUBCATEGORY_OF]->() " 
>       + "RETURN distinct cat as category, collect(subCat) as subCategories") 
>  Iterable<CategoryDAO> getAll();
> 
> When i call this method, i get an exception:
> 
> java.lang.RuntimeException: Cannot extract single value from Iterable with 
> more than one elements.
>  at 
> org.springframework.data.neo4j.conversion.DefaultConverter.extractSingle(DefaultConverter.java:60)
>  at 
> org.springframework.data.neo4j.conversion.DefaultConverter.extractValue(DefaultConverter.java:51)
>  at 
> org.springframework.data.neo4j.conversion.DefaultConverter.convert(DefaultConverter.java:40)
>  at 
> org.springframework.data.neo4j.support.conversion.EntityResultConverter.convert(EntityResultConverter.java:165)
>  at 
> org.springframework.data.neo4j.conversion.DefaultConverter.convert(DefaultConverter.java:36)
>  at 
> org.springframework.data.neo4j.rest.SpringRestGraphDatabase$SpringResultConverter.convert(SpringRestGraphDatabase.java:148)
>  at 
> org.neo4j.rest.graphdb.util.QueryResultBuilder$1$1.underlyingObjectToObject(QueryResultBuilder.java:98)
>  at org.neo4j.helpers.collection.IteratorWrapper.next(IteratorWrapper.java:47)
>  ...
>  ...
> 
> 
> I think my code is quite similar with the exemple in documentation at 
> http://docs.spring.io/spring-data/data-neo4j/docs/3.0.0.M1/reference/htmlsingle/#reference_programming-model_mapresult
> 
> Please could you tell me what i'm doing wrong ?
> 
> Tank you
> 
> 
> 
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