C# to Java type mapping

[niemyjski]

I have a dictionary that I do dynamic mapping on in our app. I append a type suffix to the field name so I can share mappings (multi tenant). Currently I'm only handling decimal and double mappings in .net and this leads to some insert errors when I detect it incorrectly (obviously a bug on our part).. I think the solutions for us going forward is to have a typed field mapping based on the suffix that maps to the largest numeric type (sucks because you use more memory) or parse out the specific type (and use more processing time).

I wanted to look through your code to see if I could find a method where I could pass a type/instance or string (do a parse of the type for me) and return the name it would be mapped to (E.G., number). I came across this and this in master. To my knowledge, correct me if I'm wrong.. seem to incorrectly handle some data types incorrectly or not at all. For example it doesn't seem like some data types are handled like DateTimeOffset and possibly some numeric types. Secondly the java types as defined here don't match up with your .NET data type mappings. Example:

Java byte is -128 to 127 which is the same as a .NET SByte. In the code I saw you had it mapped to a .NET Byte as well which is 0-255. Which I believe the methods would return the incorrect mapping if the value is >127.

Would it be possible to expose some helper methods that make it easier to get the mapped types as well as update these mappings?

[russcam]

@niemyjski thanks for reporting this. I'm looking at this in the 2.0 branch, with the following C# to Elasticsearch data type mappings:

.NET Type	Elasticsearch Type
System.Byte	short
System.Int16	short
System.Int32	integer
System.Int64	long
System.Single	float
System.Double	double
System.Decimal	double
System.SByte	byte
System.UInt16	integer
System.UInt32	long
System.UInt64	double
System.Boolean	boolean
System.Char	string
System.String	string
System.Guid	string
System.DateTime	date
System.DateTimeOffset	date

/cc @gmarz @Mpdreamz, I think we should consider also handling System.TimeSpan by default, storing it as a double representing the TotalMilliseconds of the TimeSpan. Storing it as a string makes less sense to me as you may want to query on the field and this would be unituitive on a string field.

Within the 2.0 branch, you can use the PropertyWalker to get the mapped properties for a given type.

[Mpdreamz]

Closing this as we are doing the correct thing in 2.0 (unless i'm going crosseyed @niemyjski @russcam please reopen!)

[russcam]

@Mpdreamz We adhere to the above mappings in 2.0 (and also have been backported to the next release of 1.x).

The only remaining consideration is handling TimeSpan by default - this would require a custom JsonConverter to handle serialization/deserialization to and from a double. I'll open as a separate issue for consideration.

[niemyjski]

@russcam was this back ported to 1.8?

[russcam]

@niemyjski yes, it went into 1.7.2 in aa8c993