loadPage().next(bundle).execute() would lead to infinite loop - hl7-fhir

Question

I am trying to get all the entries in a paginated bundle.
The working code is as follow:
Bundle bundle = fhirClient.search()
.forResource(...)
.where(...)
.returnBundle(Bundle.class)
.execute();
if (bundle == null){
return null;
}
// Keep adding entries until the last page
Bundle tempBundle = fhirClient.loadPage().next(bundle).execute();
// Put all the new entries into a separated list so that we do not modify the iterator
List<Bundle.Entry> entries = new ArrayList<>();
while(tempBundle != null){
entries.addAll(tempBundle.getEntry());
if(tempBundle.getLink(Bundle.LINK_NEXT) != null) {
tempBundle = fhirClient.loadPage().next(tempBundle).execute();
}
else{
tempBundle = null;
}
}
entries.forEach(bundle::addEntry);
return bundle;
However, I was doing something like this in the while loop and it would end up in infinite loop:
while(tempBundle != null){
entries.addAll(tempBundle.getEntry());
tempBundle = fhirClient.loadPage().next(tempBundle).execute();
}
I was expecting the tempBundle would end up with null for a bundle without the next page, but it would never happen. Any idea?

Answer 1

You might want to take a look at this Example:
BundleFetcher.java
Especially the part where you populate the results with the following pages:
while (bundle.getLink(IBaseBundle.LINK_NEXT) != null) {
bundle = client
.loadPage()
.next(bundle)
.execute();
patients.addAll(BundleUtil.toListOfResources(ctx, bundle));
}
I think the offending part in your code is
// Keep adding entries until the last page
Bundle tempBundle = fhirClient.loadPage().next(bundle).execute();