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https://issues.apache.org/jira/browse/SLING-10502?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17366501#comment-17366501
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Bertrand Delacretaz commented on SLING-10502:
---------------------------------------------
I haven't found a nice pattern with {{Optional}}, didn't find an elegant way to
set the value on first use.
Here's a simple {{LazyLoader}} helper that does the job, complete example at
https://gist.github.com/bdelacretaz/d0b12a4eec4c134fdbea06aba66de907
{code}
class LazyLoader<T> {
private final Supplier<T> sup;
private T value;
LazyLoader(Supplier<T> sup) {
this.sup = sup;
}
T get() {
if(value == null) {
synchronized(this) {
if(value == null) {
value = sup.get();
}
}
}
return value;
}
}
class LazyLoadingPojo {
LazyLoader<Integer> count = new LazyLoader<>(this::computeCount);
public int getCount() {
return count.get();
}
private int computeCount() {
return ++callCount;
}
}
{code}
> Helpers for lazy loading of GraphQL query results
> -------------------------------------------------
>
> Key: SLING-10502
> URL: https://issues.apache.org/jira/browse/SLING-10502
> Project: Sling
> Issue Type: Improvement
> Components: GraphQL
> Affects Versions: GraphQL Core 0.0.10
> Reporter: Bertrand Delacretaz
> Priority: Minor
>
> Lazy loading of "expensive" field values can help the performance of GraphQL
> queries, by omitting calls to methods that retrieve or compute data if the
> corresponding fields are not used in the result set.
> A natural way of doing that is to return a {{Supplier<SomeType>}} instead of
> {{SomeType}} directly. I'm not sure if the GraphQL Core supports that
> correctly out of the box, it would be good to try that and maybe implement
> the corresponding improvements.
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