Let, LetMany Variable Support

[lopezton-anthem]

Description

Adding @Let support, a mechanism for providing resolved values for provided keywords within an execution context.

// static value replacement
@Let(name = "foo", value = "/configVariables/p0")
@Config(url = "<!foo!>/_process?fn=_set&value=p1-did-it")
private String p1;

// param path resolver replacement (using reserved keyword) + transitivity
@Let(name = "bar", value = "<!#this!>/../p0")
@Let(name = "baz", value = "p2-did-it")
@Config(url = "<!bar!>/_process?fn=_set&value=<!baz!>")
private String p2;

// spel expression replacement
@Let(name = "foo", spel = "LocalDateTime.now()")
@Config(url = "<!#this!>/../date/_process?fn=_set&value=<!foo!>")
private String p3;

Overview of Changes

• Refactored DefaultCommandPathVariableResolver to use Resolver interfaces for resolver implementations.
  • The names of the "reserved keywords" are now maintained by ReservedKeywordRegistry, which is used to ensure @Let does not allow for overriding "reserved keywords" (like #this, #self, etc.)
  • Custom resolvers can be registered via DefaultCommandPathVariableResolver.registerResolver(Resolver resolver) if needed.
• Introduced @Let and @LetMany to resolve values within an ExecutionContext
  • value - static values
  • spel - spel expression
• Added a resolvedVariableMap to ExecutionContext to maintain the resolved variables during the execution process.

Type of Change

• New feature
• Refactor/Technical Debt
• This change requires a documentation update

Test Details

• DefaultConfigVariableResolverTest

Additional Notes

N/A

[openanthem-admin]

You did it @lopezton-anthem!

Thank you for signing the Anthem Opensource Software CLA.

[lopezton-anthem]

This feature is an experimental feature I thought up while trying to dream up "helpful" features. I don't know if it will have a high use case, but I've seen a lot of hard-to-read @Config statements so I thought I'd take this up in some spare time.

[lopezton-anthem]

@soham-anthem Thoughts on using resolvedVariableMap in ExecutionContext for this? My only concern is the need to clear the maps once the execution has finished to give up the object references.

[openanthem-admin]

You did it @lopezton-anthem!

Thank you for signing the Anthem Opensource Software CLA.