android - Rxjava Filtering the duplicate item in List -

i using rxjava , retrofit in app.here's setup of app.when app launched app make 2 request 1 database , other network api (using retrofit) , both request return observable<list<article>>. did merged 2 observable. problem network return articles present in database. how filter out duplicate item list. here's code.

return observable.merge(datasource.getarticles(source), remotesource.getarticles(source))             .distinct(); 

so tried distinct operator it's not filtering articles out.here's output looks form db.

article1 article2 article3 article4 

output network

article7 articke8 article3 article4 

what want distinct list of article

assuming article has proper equals implementation,

you collect them set:

 datasource.getarticles(source)     .mergewith(remotesource.getarticles(source))     .collect(hashset::new, (set, list) -> set.addall(list)) 

or unroll each list , apply distinct followed tolist:

 datasource.getarticles(source)     .mergewith(remotesource.getarticles(source))     .flatmapiterable(v -> v)     .distinct()     .tolist()