Allow to specify highlighter parameters on a per field level basis

[lukas-vlcek]

Now it is possible to override global highlighter settings at the field level. On top of this it is also possible to specify "fragment_type" : "content" which will return highlighted content of the field (no fragments).

[kimchy]

Few changes that I plan to push:

• The global setting are not used. Also, you can't rely on the order the elements arrive in the json (so the globals are set before the fields).
• You can't rely on hashcode to provide uniqueness when constructing the map key.
• I am going to simplify things a bit in how thins are parsed (no need for global element).
• Also, single fragment builder will be used when setting number of fragments to 0.

[kimchy]

Allow to specify highlighter parameters on a per field level basis, closed by cc1eac1.

[lukas-vlcek]

Cool, just the javadoc needs to be updated according to the changes: http://github.com/elasticsearch/elasticsearch/blob/cc1eac147a5278b46dfa18481dbbd2ed2461aa19/modules/elasticsearch/src/main/java/org/elasticsearch/search/highlight/HighlighterParseElement.java#L44
Replace "fragment_type" : "content" with "number_of_fragments" : 0

[lukas-vlcek]

There is one major issue. If numberOfFragments is 0 then the Highlighter does not produce any fragments. Dirty workaround is to add the following line of code after this line: http://github.com/elasticsearch/elasticsearch/blob/cc1eac147a5278b46dfa18481dbbd2ed2461aa19/modules/elasticsearch/src/main/java/org/elasticsearch/search/highlight/HighlightPhase.java#L100

field.numberOfFragments(1);

[lukas-vlcek]

I think it needs to be set to any number greater then 0. I did not check the Lucene source code but after I did the above change then the highlighter correctly yielded whole field content with highlighted text.

[kimchy]

applied.