Java Community | Help. Code. Learn.•2y ago

Custom Collector

i try to write a custom collector, but the supllier function keeps saying type mismatch. the input is a ResourceType, the output should be a set of strings. im not sure what type i should name for the accumulator function tho ^^" (java version 20 i think)

public interface KeywordCollector extends Collector<RessourceType, List<String>, Set<String>> {}



public class PlainTextCollector implements KeywordCollector {
 public Supplier<List<String>> supplier() {
        return new ArrayList<String>();
    }
    }

public interface KeywordCollector extends Collector<RessourceType, List<String>, Set<String>> {}



public class PlainTextCollector implements KeywordCollector {
 public Supplier<List<String>> supplier() {
        return new ArrayList<String>();
    }
    }

Type mismatch: cannot convert from List<String> to Supplier<List<String>>Java(16777235)

6 Replies

JavaBot•2y ago

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Kyo-chan•2y ago

You're supposed to return a supplier of lists, not just one list

' .•` KIΛ.RΛR ’•. 'OP•2y ago

whatb is a supllier of lists?

Kyo-chan•2y ago

It's something that supplies a list, curiously enough. Usually by creating it try return ArrayList::new;

' .•` KIΛ.RΛR ’•. 'OP•2y ago

thx!

JavaBot•2y ago

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