[DELTASPIKE-1335] allow atomic access to n different TypedResolver values

• Type: New Feature
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.9.0
• Fix Version/s: 1.9.0
• Component/s: Configuration
• Assignee: Mark Struberg
• Reporter: Mark Struberg
• Created: 04/Apr/18 11:23
• Updated: 07/Sep/18 09:09
• Resolved: 07/Sep/18 09:09

Description

If multiple related config values (TypedResolver) are accessed in the same request and the underlying config changes then we might up with a wild mixture of old and new values.

An example would be to access some 'myapp.host' and 'myapp.port':
The underlying values are 'oldserver' and '8080'.

Now consider the following code:

 // get the current host value
TypedResolver<String> hostCfg config.resolve("myapp.host");

// and right inbetween the underlying values get 
// changed to 'newserver' and port 8082

// get the current port for the host
TypedResolver<Integer> portCfg config.resolve("myapp.port");

In ths above code we would get the combination of 'oldserver' but with the new port 8081. And this will obviously blow up because that host+port combination doesn't exist.