I have a List of matches. A match has a property called matchIndex. Now I want to set the property of each match in list like this
index = 0 // some predefined value
List<Match> matchList = createMatches(membersList, teamsPerGroup,totalGroups);
matchList.forEach((match) -> {
match.setMatchIndex(index++);
});
I want to set matchIndex of each match in the list by increasing order after local variable index.
You can't use this because variables in lambda should be final or effectively final. you can follow this code:
IntStream.range(0, matchList .size())
.mapToObj(index -> {
Match match= list.get(index);
match.setMatchIndex(index);
return match;
})
.collect(Collectors.toList());
or use AtomicInteger
AtomicInteger index= new AtomicInteger(1);
matchList.forEach(match-> match.setMatchIndex(index.getAndAdd(1)));
UPDATE:
As @Holger commented The correct solution is
IntStream.range(0, matchList.size())
.forEach(index -> matchList.get(index) .setMatchIndex(index));
and if you want to use some predefined value this is right solution:
IntStream.range(0, matchList.size())
.forEach(index -> matchList.get(index) .setMatchIndex(index + offset));
IntStream.range(0, matchList.size()) .forEach(index -> matchList.get(index) .setMatchIndex(index)); And, by the way, why do you initialize the AtomicInteger with one, contradicting every other example?IntStream.range(0, matchList.size()) .forEach(index -> matchList.get(index) .setMatchIndex(index + offset));Actually, there is a lazy way to do it but it's not the Java 8 way. Still, I am posting this answer:)
int index = 0; // starting index
for (Match match: matchList) {
match.setMatchIndex(matchIndex++);
}
Hope it helps.
final int index = 0;