Searching API improvements

[gorbunkov]

Option 1

We may implement an approach similar to Jmix FileStorage.

public interface Searcher { 
   String getName();

   SearchResult search(String query);
   SearchResult search(String query, SearchContext context); // move query into context?
}

public interface SearcherLocator {
   Searcher getByName(String name);
   Searcher getDefault();
}

public class SearchContext {
    long size;
    long offset;
    String query;
}

There may be multiple Searcher implementations - each uses its own search strategy: term search, search by query, etc. Each searcher has a name. SearcherLocator locates searchers by name. One of the searchers is a default searcher (defined by configuration property).

There must be a way to define which indexes (for what entities) we want to search.

A searcher name may be defined for a searchField component:

<search:searchField id="sf1" searcher="term"/>

Option 2

There will be a single Searcher implementation. There may be multiple SearchStrategy instances

public interface Searcher { 
   SearchResult search(String query);
   SearchResult search(SearchContext context);
   SearchResult search(SearchContext context, SearchStrategy searchStrategy);
}

public class SearchContext {
    long size;
    long offset;
    String query;
}

public interface SearchStrategy {
    String getName();
    SearchRequest buildSearchRequest(SearchContext searchContext);   
}

public interface SearchStrategyLocator {
   Searcher getByName(String name);
   Searcher getDefault();
}

Misc

Also consider implementing an API for transforming SearchResult (it contains a list of SearchResultEntry, each entry stores a collection of FieldHit) into a collection of entities.