package io.sourcy.playground.java;

import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.stream.Collectors;

public class MyCollectors {
    public Map<String, String> groupByKeysAndJoinValues(List<KeyValuePair> keyValuePairs) {
        return keyValuePairs.stream()
                .collect(Collectors.groupingBy(KeyValuePair::getTheKey, LinkedHashMap::new, Collectors.toList()))
                .entrySet().stream().collect(Collectors.toMap(Map.Entry::getKey, entry -> joinValues(entry.getValue())));
    }

    private String joinValues(List<KeyValuePair> valueList) {
        return valueList.stream().map(KeyValuePair::getTheValue).sorted().collect(Collectors.joining(", "));
    }
}