First I need to check if data is present in list then get else set default or empty value on a Java 8 stream.
Currently I am using below code without isPresent but I dont know how to use isPresent in java8.
I am trying something below which is not perfect:
String isScheme = (this.mapProgramApproaches.stream().findFirst().isPresent())? this.mapProgramApproaches.stream().findFirst().get().getIsScheme().toString() : "0";
Where as mapProgramApproaches this is set.
Don't use isPresent() (it makes no sense to run the Stream pipeline twice).
You can use map to map the value of the Optional to the required String, and then
use orElse() to return a default value when the Optional value is not present:
String isScheme = this.mapProgramApproaches.stream()
.findFirst()
.map(o->o.getIsScheme().toString())
.orElse("0");
Maybe you are looking for something like this:
String isScheme = this.mapProgramApproaches.stream()
.findFirst()
.map(p -> p.getIsScheme().toString())
.orElse("0");
I'm not sure about context in which you are doing this, but I suppose that you would like to check whether some object is scheme and then do something with that. In that case I would suggest implement it like this:
List<String> mapProgramApproaches = new ArrayList<>();
mapProgramApproaches.stream()
.filter(this::isScheme)
.findFirst()
.ifPresent(this::doYourCode)
.orElse(defaultValue);
It will make your code cleaner. And will help to avoid additional conditionals!
