for(Fees fee : feeList) {
if(fee.getType().equalsIgnoreCase(feeType)) {
baseFee = fee.getAmountFee();
break;
}
}
I wanted to know if it's possible to convert the above example to a single stream where there is a for loop.
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Yes, that is quite possible. And it's not all that difficult. stream -> filter -> findFirst -> if present ...Stultuske– Stultuske2023-01-20 10:08:22 +00:00Commented Jan 20, 2023 at 10:08
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for (ItemDO item : updateItems.getItemsDO().getItems()) how to do if loop given like this @Stultuske.lokesh598– lokesh5982023-01-20 14:20:25 +00:00Commented Jan 20, 2023 at 14:20
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SO is not about handing you custom code. We either put you on the right path, or, if you've already tried, help you correct your code. So far, I haven't even seen you attempt to create a Stream.Stultuske– Stultuske2023-01-20 14:23:10 +00:00Commented Jan 20, 2023 at 14:23
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2 Answers
Certainly, you can convert it as follows:
Optional<Double> optionFeeAmount = feeList
.stream()
.filter(fee -> feeType.equalsIgnoreCase(fee.getType()))
.findFirst()
.map(Fees::getAmountFee);
You can add orElse(0) at the end, if you want to return 0 as a default result. Also you can use findAny() if the sequence in list doesn't matter.
1 Comment
Holger
@lokesh598 this does already stop at the first match and return it. No need for a “break” statement
Yes possible, something like:
baseFee = feeList.stream().filter(fee -> fee.getType().equalsIgnoreCase(feeType))
.map(Fees::getAmountFee)
.findFirst()
.orElse(baseFee);
Solution explanation:
filterfunction replace the if conditionmapfunction will replace everyFeeswith theiramountFeefindFirstfunction will do the same job asbreak;and will return on the first match.orElseif there is no match I kept the samebaseFeevalue
The stream API (functional programming) is smart enough in performance meaning that it will not filter everything and then do the map, instead it will do it in its way, with good performance.
