Details
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Improvement
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Status: Resolved
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Minor
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Resolution: Fixed
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2.4.0SDK
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None
Description
Extend the binary compressed serialization to support cases where the type systems are not exactly the same.
There are 2 use cases.
First: the source is a previously saved file. The goal is to deserialize it into e.g. a tool, where the type system in the tool may be somewhat different than the type system used to create the file. (For instance, it may be at a different version level).
Second: the source is a client for a UIMA-AS service. In this case, the client has read the service's type system, and has merged it with its own.
Difference in the type systems could be:
Type exists in one, not in the other;
Type exists in both, but with different features (including those from super types). Features could be added/subtracted. Features could have different ranges (incompatible ranges should cause error messages).
A suggested impl approach: create a mapper that maps typecodes and feature codes; set it up by comparing two type systems. For the first use case, implement a version of deserialization that takes an extra input of the source type system, and creates the converter, and then does deserialization with the conversions. For the 2nd use case, during initialization time, after the service's type system has been read (for merging into the client's type system definition), use this to create the same mappper between type codes / feature codes; when sending a CAS via binary serialization, send it via the mapping converter for type codes and feature codes.
Try to arrange things so that the creation of the mapper can be done once per "set" of CASes, rather than once per CAS.
Note that managing out-of-type-system data is superseded by support for delta-CAS formats.