How to cache only when the json is valid - spring

Question

I have a spring rest api application that is using HATEOAS/PagingAndSortingRepository to do most of the heavy lifting.
I have implemented caching using guava but I am having issues where when the user cancels the request midway through an api call, it caches the incomplete json and re-serves it for 60 seconds.
I am trying to use the unless="" parameter of the #Cacheable annotation. Previously, I just used unless="#result == null" but that does not handle incomplete or invalid json.
This does not seem to work either. So now I am trying to use com.google.gson.JsonParser to parse the result and invalidate if applicable.
Repository
#RepositoryRestResource(path = "products", collectionResourceRel = "products")
public interface ProductEntityRepository extends PagingAndSortingRepository<ProductEntity, String> {
JsonParser parser = new JsonParser();
#Cacheable(value = CacheConfig.STORE_CACHE)
ProductEntity findByName(String name);
}
Cache Config
public final static String PRODUCTS_CACHE = "products";
#Bean
public Cache productsCache() {
return new GuavaCache(PRODUCTS_CACHE, CacheBuilder.newBuilder()
.expireAfterWrite(60, TimeUnit.SECONDS)
.build());
}
How do I detect invalid json in the unless="" parameter?

Answer 1

I figured out my own issue!
When I interrupted the api request to localhost/products and re-requested, I finally saw an error about not being able to fetch a onetomany mapping. I believe the error was lazy initialization error for a collection.
I solved this issue by adding #LazyCollection(LazyCollectionOption.FALSE) to my models where the #OneToMany and #ManyToOne mappings were decalared.
For example:
#Entity(name = "product")
#Table(name = "products", schema = "${DB_NAME}", catalog = "")
public class ProductEntity {
private Integer id;
private String name;
private List shipments = new ArrayList<>();
#Id
#Column(name = "id", nullable = false)
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
#Basic
#Column(name = "name", nullable = false, length = 10)
public String getName() { return name; }
public void setName(String name) {
this.name = name;
}
#OneToMany(mappedBy = "shipmentID", targetEntity=ShipmentEntity.class)
#LazyCollection(LazyCollectionOption.FALSE)
public Collection<ShipmentEntity> getShipments() { return shipments; }
public void setShipments(Collection<ShipmentEntity> shipments) { this.shipments = shipments; }
}