public U constructInstance()

in repository/src/main/java/org/apache/atlas/discovery/graph/DefaultGraphPersistenceStrategy.java [128:200]
61 lines of code
14 McCabe index (conditional complexity)

    public <U> U constructInstance(IDataType<U> dataType, Object value) {
        try {
            switch (dataType.getTypeCategory()) {
            case PRIMITIVE:
            case ENUM:
                return dataType.convert(value, Multiplicity.OPTIONAL);
            case ARRAY:
                DataTypes.ArrayType arrType = (DataTypes.ArrayType) dataType;
                IDataType<?> elemType = arrType.getElemType();
                ImmutableCollection.Builder result = ImmutableList.builder();
                List list = (List) value;
                for(Object listElement : list) {
                    Object collectionEntry = constructCollectionEntry(elemType, listElement);
                    if(collectionEntry != null) {
                        result.add(collectionEntry);
                    }
                }
                return (U)result.build();
            case MAP:
                // todo
                break;

            case STRUCT:
                AtlasVertex structVertex = (AtlasVertex) value;
                StructType structType = (StructType) dataType;
                ITypedStruct structInstance = structType.createInstance();
                TypeSystem.IdType idType = TypeSystem.getInstance().getIdType();

                if (dataType.getName().equals(idType.getName())) {
                    structInstance.set(idType.typeNameAttrName(), GraphHelper.getSingleValuedProperty(structVertex, typeAttributeName(), String.class));
                    structInstance.set(idType.idAttrName(), GraphHelper.getSingleValuedProperty(structVertex, idAttributeName(), String.class));
                    String stateValue = GraphHelper.getSingleValuedProperty(structVertex, stateAttributeName(), String.class);
                    if (stateValue != null) {
                        structInstance.set(idType.stateAttrName(), stateValue);
                    }
                    structInstance.set(idType.versionAttrName(), structVertex.getProperty(versionAttributeName(), Integer.class));
                } else {
                    metadataRepository.getGraphToInstanceMapper()
                        .mapVertexToInstance(structVertex, structInstance, structType.fieldMapping().fields);
                }
                return dataType.convert(structInstance, Multiplicity.OPTIONAL);

            case TRAIT:
                AtlasVertex traitVertex = (AtlasVertex) value;
                TraitType traitType = (TraitType) dataType;
                ITypedStruct traitInstance = traitType.createInstance();
                // todo - this is not right, we should load the Instance associated with this
                // trait. for now just loading the trait struct.
                // metadataRepository.getGraphToInstanceMapper().mapVertexToTraitInstance(
                //        traitVertex, dataType.getName(), , traitType, traitInstance);
                metadataRepository.getGraphToInstanceMapper()
                    .mapVertexToInstance(traitVertex, traitInstance, traitType.fieldMapping().fields);
                break;

            case CLASS:
                AtlasVertex classVertex = (AtlasVertex) value;
                String guid = classVertex.getProperty(Constants.GUID_PROPERTY_KEY, String.class);
                // Check if the instance we need was previously loaded.
                ITypedReferenceableInstance classInstance = RequestContext.get().getInstanceV1(guid);
                if (classInstance == null) {
                    classInstance = metadataRepository.getGraphToInstanceMapper().mapGraphToTypedInstance(guid, classVertex);
                }
                return dataType.convert(classInstance, Multiplicity.OPTIONAL);

            default:
                throw new UnsupportedOperationException("Load for type " + dataType + "is not supported");
            }
        } catch (AtlasException e) {
            LOG.error("error while constructing an instance", e);
        }

        return null;
    }