Java 8 - How to search a MultiValueMap with value?

Question

I have a

MultiValueMap<String, String> map = new LinkedMultiValueMap<>();

The type of value is a list of strings:

List<String> valueList = map.get('key');

How can i search through this map (through all the valueLists within this map) and get all the values which startsWith 'xy' in a list back?

I hope the question is clear.

I have tried this, but no success:

  map
    .entrySet()
    .stream()
    .filter(e-> e.getValue().stream().filter(value -> value.startsWith(searchString)))
    .collect(Collectors.toList());

I get this error: Stream cannot be converted to boolean

`map with single values` meaning a `List` where size == 1? – Eugene Sep 25 '18 at 14:16 — Eugene, Sep 25 '18 at 14:16
sorry.. no.. lists can have many values – akcasoy Sep 25 '18 at 14:24 — akcasoy, Sep 25 '18 at 14:24

Eugene · Accepted Answer · 2018-09-25T14:26:04.817

1

If I understood your problem correctly:

map.values()
    .stream()
    .flatMap(List::stream)
    .filter(x -> x.startsWith(searchString))
    .collect(Collectors.toList())

edited Sep 25 '18 at 14:26

answered Sep 25 '18 at 14:20

Eugene

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but you just check the first elements of list, which also have exactly 1 value. I want to search ALL values in ALL lists. Lists can also have many values.. a typical MultiValueMap – akcasoy Sep 25 '18 at 14:23
@akcasoy didn't you say yourself: *How can i search this map with single values*? – Eugene Sep 25 '18 at 14:24
@akcasoy so you want to search across all values, right? – Eugene Sep 25 '18 at 14:24
i have reformulated my question – akcasoy Sep 25 '18 at 14:25
@akcasoy and I did my answer – Eugene Sep 25 '18 at 14:26
thank you.. do u know how i can at the end filter the duplicates ? – akcasoy Sep 25 '18 at 14:48
ok. toSet() instead of toList helped ;) – akcasoy Sep 25 '18 at 14:53

Java 8 - How to search a MultiValueMap with value?

1 Answers1