Tika Metadata Add performance optimization

[patrickdalla]

Discussed in #2039

^{Originally posted by patrickdalla January 2, 2024}
Hi @wladimirleite , I'm back to work after my licences/vacation. I opened this discussion based on the performance issue you also noted when implementing #1999, about the bad implementation of metadata addition on multi valued metadata field. In that PR it seems that you found a different approach that do not need multivalue.
But the performance issued still exists, and affects any other parser that needs to add multiple metadata. Have you opened an specific issue to address this problem?

[patrickdalla]

Hi @wladimirleite, I was able to bybass and override protected original Tika implementation of metadata, at least in a level that could solve the problem of adding multiple values at once.
I created a MetadataWriteFilter implementation that does not set the metadata in the first and subsequent value additions, only in the last. The only problem is that, to know that the value is the last to be added, a initial call to allocateSpace method must be called.

So it was enough to set multiple values at once from an ArrayList of a single Parser avoiding the slow tika implementation. This is what I needed in SQLite split PR.