CODEWITHSUNDEEP
javajava-stream
Хамидилло Мамытов
Хамидилло Мамытов

Reputation: 110

How to write code simply using stream api

I have the following classes:

@Getter
public class SomeClass implements Serializable {
    private LocalDate date;
    private String smth;
    List<PairKeyValue> quotaParams;
}

The class PairKeyValue is just:

@Getter
public class PairKeyValue implements Serializable {

    private String key;
    private String value;
}

I want to do the following:

1) Check if in SomeClass's date equals sysdate then check value under key="somekey" in list<PairKeyValue> is equals to 1 (somekey = 1) then left it in list.

2) Check if in SomeClass's date NOT equals sysdate then check value under key="somekey" in List<PairKeyValue> is equals to 0 (somekey = 0) then left it in list.

3) And ignore other values.

So in the end I need a filtered list of only current values within SomeClass.

I have my realization but I don't like it is not using only stream API:

availableQuotes = ArrayList();

 if (CollectionUtils.isNotEmpty(availableQuotes)) {
        availableQuotes = availableQuotes
                .stream()
                .filter(this::checkDate).collect(toList());
    }

    private boolean checkDate (SomeClass someClass){
        if (someClass.getDate().equals(LocalDate.now())) {
            return checkDuration(someClass, "0");
        } else {
            return checkDuration(someClass, "1");
        }
    }

    private boolean checkDuration (SomeClass someClass, String param){
        List<PairKeyValue> quotaParams = someClass.getPairKeyValues().stream()
                .filter(spKeyValue -> spKeyValue.getKey().equals("duration"))
                .filter(spKeyValue -> spKeyValue.getValue().equals(param))
                .collect(toList());
        return (CollectionUtils.isNotEmpty(quotaParams));
    }

I know it looks awful and I know it can be more readable so please help.

Upvotes: 0

Views: 92

Answers (1)

Paul Lemarchand
Paul Lemarchand

Reputation: 2096

If I understood your question right, the last 2 functions can be resumed to the following:

availableQuotes = availableQuotes.stream()
            .filter(availableQuote -> availableQuote.getQuotaParams().stream()
                    .anyMatch(quotaParam -> quotaParam.getKey().equals("duration")
                            && quotaParam.getValue().equals(availableQuote.getDate().equals(LocalDate.now()) ? "0" : "1")))
            .collect(Collectors.toList());

I mostly took your code and re-arranged it into a single filter.

Upvotes: 1

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