feat: add LOCATE predicate for JPA entity attributes annotated with @Convert

[igdianov]

Fixes #112

This PR adds support for LOCATE predicate for JPA entity class attributes annotated with @Convert, i.e.

Given entity class with JsonNode attribute:

@Entity(name = "JsonEntity")
@Table(name = "json_entity")
@Data
public class JsonEntity {
 
    @Id
    private int id;
 
    private String firstName;
 
    private String lastName;
 
    @Convert(converter = JsonNodeConverter.class)
    @Column(columnDefinition = "text")
    private JsonNode attributes;
    
}

And JsonNodeConverter implementation:

public class JsonNodeConverter implements AttributeConverter<JsonNode, String> {
    private final static Logger logger = LoggerFactory.getLogger(JsonNodeConverter.class);
    
    private static final ObjectMapper objectMapper = new ObjectMapper()
                                                            .disable(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES);
    @Override
    public String convertToDatabaseColumn(JsonNode jsonMap) {
 
        String jsonString = null;
        try {
            jsonString = objectMapper.writeValueAsString(jsonMap);
        } catch (final JsonProcessingException e) {
            logger.error("JSON writing error", e);
        }
 
        return jsonString;
    }
 
    @Override
    public JsonNode convertToEntityAttribute(String jsonString) {
 
        JsonNode jsonMap = null;
        try {
            jsonMap = objectMapper.readValue(jsonString, JsonNode.class);
            
        } catch (final IOException e) {
            logger.error("JSON reading error", e);
        }
 
        return jsonMap;
    }
 
}

With attributes json string data stored in the record:

-- Json entity
insert into json_entity (id, first_name, last_name, attributes) values
	(1, 'john', 'doe', '{"attr":{"key":["1","2","3","4","5"]}}'),
	(2, 'joe', 'smith', '{"attr":["1","2","3","4","5"]}');

When the following query is executed:

query {
    JsonEntities(where: { 
       attributes: {LOCATE: "key"} 
    }) {
      select {
      id
      firstName
      lastName
      attributes
    }
  }
}

The expected result:

{
   "JsonEntities":{
      "select":[
         {
            "id":1,
            "firstName":"john",
            "lastName":"doe",
            "attributes":{
               "attr":{
                  "key":[ "1", "2", "3", "4", "5"]
               }
            }
         }
      ]
   }
}

[codecov]

Codecov Report

Merging #115 into master will increase coverage by 0.56%.
The diff coverage is 91.66%.

@@             Coverage Diff              @@
##             master     #115      +/-   ##
============================================
+ Coverage     65.81%   66.37%   +0.56%     
- Complexity      368      372       +4     
============================================
  Files            37       37              
  Lines          2024     2034      +10     
  Branches        299      302       +3     
============================================
+ Hits           1332     1350      +18     
+ Misses          562      552      -10     
- Partials        130      132       +2

Impacted Files	Coverage Δ	Complexity Δ
...ry/schema/impl/GraphQLJpaOneToManyDataFetcher.java	73.68% <ø> (-0.46%)	13 <0> (ø)
...graphql/jpa/query/schema/impl/PredicateFilter.java	96.96% <100%> (+0.09%)	4 <0> (ø)	⬇️
...jpa/query/schema/impl/GraphQLJpaSchemaBuilder.java	86.83% <100%> (+0.19%)	105 <0> (+2)	⬆️
...hql/jpa/query/schema/impl/JpaPredicateBuilder.java	46.63% <50%> (+0.51%)	42 <0> (+1)	⬆️
...ventures/graphql/jpa/query/schema/JavaScalars.java	36.32% <0%> (+3.41%)	4% <0%> (+1%)	⬆️

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