[FIXED] How to filter a list of String down to a distinct list made of string suffices in Java 8 Streams

Issue

I am new to Java streams but need to master by practice really!

The collection input is made up of strings e.g. [name][dot][country], example as follows:

JAMES.BRITAIN
JOHN.BRITAIN
LEE.BRITAIN
GEORGE.FRANCE
LEON.FRANCE
MARSELLE.FRANCE
KOFI.GHANA
CHARLIE.GHANA

Please, how do I return a list of unique countries in a single stream statement?

Expected result will be a distinct list as follows:

BRITAIN
FRANCE
GHANA

In the real code the streams statement below gives me the list to be filtered i.e.:

List<String> allSolrCollections =  (List<String>) findAllCollections()
    .getJsonArray(SOLR_CLOUD_COLLECTION)
    .getList()
    .stream() 
    .map(object -> Objects.toString(object, null))
    .collect(Collectors.toList());

Solution

Alternative solution

You can use the advantage of the method Pattern#splitAsStream(CharSerquence). Once you split each line into a new Stream, skip the first item, flatMap the result into a new Stream and produce a Set.

final Pattern pattern = Pattern.compile("\\.");

final Set<String> result = list.stream()
        .flatMap(string -> pattern.splitAsStream(string).skip(1))
        .collect(Collectors.toSet());

[GHANA, FRANCE, BRITAIN]

Answered By - Nikolas Charalambidis
Answer Checked By - David Goodson (JavaFixing Volunteer)