Allow obtaining a `toString()` representation from a `Lazy` without resolving the lazy value

[Axinet]

Hello Team,

As starting with version 3.0 org.springframework.data.util.Lazy class no longer offer public contructor we can no longer wrap it in our custom implementation to check if Lazy was already resolved or not. As the member private volatile boolean resolved is already there, would it be possible to provide a public getter isResolved() to a Lazy class (I can commit it, but as this is an API change it is expected to start with disscussion)?
Our use case is: depending on resolved flag use toString of object returned from Supplier or report that something was not used yet.

[odrotbohm]

Is the sole reason for the wrapping that you need a lazy String representation? If that's the case, I'd rather add a ….toStringOrElse(Supplier<String>) that would use the given supplier if the lazy value has not been resolved yet.

[Axinet]

Yes, as for now it is the only reason. If the Lazy has been already resolved, i use resolvedObject.toString if not, use message that it has not yet been loaded (in case when the Lazy is a value of a map entry it could be "Map value for key X has not yet been loaded"). But of course don't want to have Lazy resolved only to have its value converted to string.

[odrotbohm]

I've added a defensive ….toString() and the discussed ….toString(Supplier<String>) variant. Please give the snapshots (3.0.1, 3.1) a try. We're currently planning a release at the end of next week. In case there's anything else you'd need, we could still tweak things.