Document in BatchResults needs getId()

[stevebuik]

when loading docs and checking the results, there is no easy way to get the id of any docs that failed.

we have done this using reflection but it would be much easier if there was a getId() method in Document.

or is there a better way?

[clamprecht]

Here's a patch that adds getId() method (and makes id final), I'll leave it up to the owners to pull the change in:

clamprecht@5b52a95