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javajava-streamguavamultimap

Data handling of HashMultimap

I have a HashMultimap

Multimap<String, String> map = HashMultimap.create();

The data I put into the map is

map.put("cpu", "i9");
map.put("hang", "MSI");
map.put("hang", "DELL");
map.put("hang", "DELL");
map.put("cpu", "i5");
map.put("hang", "HP");
map.put("cpu", "i7");

I have a stream

String joinString = map.entries().stream().map(e -> e.getKey() + "=" + e.getValue()).collect(Collectors.joining(" OR "));

I need the output to be

(hang=HP OR hang=MSI OR hang=DELL) AND (cpu=i9 OR cpu=i5 OR cpu=i7)

I need an AND in between the keys. How can I do that?

Solution

  • Use the Map view:

    String joined = map.asMap()
        .entrySet()
        .stream()
        .map(e -> e.getValue()
                .stream()
                .map(v -> e.getKey() + "=" + v)
                .collect(Collectors.joining(" OR ", "(", ")")))
        .collect(Collectors.joining(" AND "));