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Java 8 extract Map values ​​into array with stream and filter

Could anyone help me get an array of map values ​​with stream and filtering?

public class TheMap extends HashMap<String, String> {
    public TheMap(String name, String title) {
        super.put("name", name);
        super.put("title", title);
    }

    public static void main(final String[] args) {
        Map<Long, Map<String, String>>map = new HashMap<>();            

        map.put(0L, null);
        map.put(1L, new TheMap("jane", "engineer"));
        map.put(2L, new TheMap("john", "engineer"));
        map.put(3L, new TheMap(null, "manager"));
        map.put(4L, new TheMap("who", null));
        map.put(5L, new TheMap(null, null));
    }
}

The result I'm looking for is ArrayList<TheMap>

with just these two entries:

TheMap("jane", "engineer")
TheMap("john", "engineer")

Basically, get TheMap

named none-null

and title

.

+3


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2 answers


If you want a massive list TheMap

, try the following path:



ArrayList<TheMap> as = map.values()
   .stream()
   .filter(v -> v != null && v.get("name") != null && v.get("title") != null)
   .map(m -> (TheMap)m)
   .collect(Collectors.toCollection(ArrayList::new)));
+2


source 


List<Map<String, String>> list = 
        map.values().stream().filter(v -> 
                              v != null && 
                              !v.entrySet().isEmpty() &&
                              !v.containsValue(null)).
        collect(Collectors.toList());


+3


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