Types¶

Introduction¶

RSB is concerned with two kinds of types:

1. Wire-schemas which describe data being exchanged through transport mechanisms
2. Data-types which are restricted to individual clients, depend on the respective programming languages and describe domain objects before they get passed to RSB or after they have been obtained from RSB

The following section specifies the mapping between wire-schemas and data-types for a set of fundamental types and a generic mechanism for arbitrary user-supplied domain-objects.

Wire Schema <-> Programming Language Types Mapping¶

This section documents the mapping between wire schemas, designators of which are included in RSB's notifications, and corresponding programming language types. The values that are actually contained in notifications are called "String Designators" of wire schemas here.

Fundamental Types¶

For "fundamental" types, the mapping is based on the type mapping used by Google's protocol buffers.

Wire Schema	String Designator	C++	Python	Java	Common Lisp
No value	"void"	void	None	null	nil
Double precision float	"double"	double		double	double-float
Single precision float	"float"	float	float	float	single-float
32 bit signed integer	"int32"	int32		int	(signed-byte 32)
64 bit signed integer	"int64"	int64		long	(signed-byte 64)
32 bit unsigned integer	"uint32"	uint32		int	(unsigned-byte 32)
64 bit unsigned integer	"uint64"	uint64		long	(unsigned-byte 64)
bool	"bool"	bool	bool	boolean	boolean
ASCII string	"ascii-string"	string	str	String	string
UTF-8 string	"utf-8-string"	string	unicode	String	string
Sequence of Bytes	"bytes"	string		ByteString	(simple-array (unsigned-byte 8) (*))

Note: In C++, support for the ASCII string and UTF-8 string schemas is limited in the following ways:

• When decoding data in either schema, invalid strings will be accepted without signaling an error
• In both schemas, string values are represented as std::string objects which known nothing about the respective encodings
  • In particular, UTF-8 multi-byte sequences appear as multiple char s

Structured Data¶

• GBP for notification serialization (not exposed to user)
• A single serialization mechanism is applied for every transport in a single system
• No composite support at this level
• TODO Extend converter selection with wildcard mechnism to ease introspection and implementation of generic converters