public ITypedReferenceableInstance create()

in repository/src/main/java/org/apache/atlas/repository/memory/MemRepository.java [89:211]
80 lines of code
18 McCabe index (conditional complexity)

    public ITypedReferenceableInstance create(IReferenceableInstance i) throws RepositoryException {

        DiscoverInstances discoverInstances = new DiscoverInstances(this);

        /*
         * Step 1: traverse the Object Graph from  i and create idToNewIdMap : Map[Id, Id],
         *    also create old Id to Instance Map: oldIdToInstance : Map[Id, IInstance]
         *   - traverse reference Attributes, List[ClassType], Maps where Key/value is ClassType
         *   - traverse Structs
         *   - traverse Traits.
         */
        try {
            new ObjectGraphWalker(typeSystem, discoverInstances, i).walk();
        } catch (AtlasException me) {
            throw new RepositoryException("TypeSystem error when walking the ObjectGraph", me);
        }

        /*
         * Step 1b: Ensure that every newId has an associated Instance.
         */
        for (Id oldId : discoverInstances.idToNewIdMap.keySet()) {
            if (!discoverInstances.idToInstanceMap.containsKey(oldId)) {
                throw new RepositoryException(String.format("Invalid Object Graph: "
                                + "Encountered an unassignedId %s that is not associated with an Instance", oldId));
            }
        }

        /* Step 2: Traverse oldIdToInstance map create newInstances :
        List[ITypedReferenceableInstance]
         * - create a ITypedReferenceableInstance.
         *   replace any old References ( ids or object references) with new Ids.
        */
        List<ITypedReferenceableInstance> newInstances = new ArrayList<>();
        ITypedReferenceableInstance retInstance = null;
        Set<ClassType> classTypes = new TreeSet<>();
        Set<TraitType> traitTypes = new TreeSet<>();
        for (IReferenceableInstance transientInstance : discoverInstances.idToInstanceMap.values()) {
            try {
                ClassType cT = typeSystem.getDataType(ClassType.class, transientInstance.getTypeName());
                ITypedReferenceableInstance newInstance = cT.convert(transientInstance, Multiplicity.REQUIRED);
                newInstances.add(newInstance);

                classTypes.add(cT);
                for (String traitName : newInstance.getTraits()) {
                    TraitType tT = typeSystem.getDataType(TraitType.class, traitName);
                    traitTypes.add(tT);
                }

                if (newInstance.getId() == i.getId()) {
                    retInstance = newInstance;
                }

                /*
                 * Now replace old references with new Ids
                 */
                MapIds mapIds = new MapIds(discoverInstances.idToNewIdMap);
                new ObjectGraphWalker(typeSystem, mapIds, newInstances).walk();

            } catch (AtlasException me) {
                throw new RepositoryException(
                        String.format("Failed to create Instance(id = %s", transientInstance.getId()), me);
            }
        }

        /*
         * 3. Acquire Class and Trait Storage locks.
         * - acquire them in a stable order (super before subclass, classes before traits
         */
        for (ClassType cT : classTypes) {
            HierarchicalTypeStore st = typeStores.get(cT.getName());
            st.acquireWriteLock();
        }

        for (TraitType tT : traitTypes) {
            HierarchicalTypeStore st = typeStores.get(tT.getName());
            st.acquireWriteLock();
        }


        /*
         * 4. Traverse over newInstances
         *    - ask ClassStore to assign a position to the Id.
         *      - for Instances with Traits, assign a position for each Trait
         *    - invoke store on the nwInstance.
         */
        try {
            for (ITypedReferenceableInstance instance : newInstances) {
                HierarchicalTypeStore st = typeStores.get(instance.getTypeName());
                st.assignPosition(instance.getId());
                for (String traitName : instance.getTraits()) {
                    HierarchicalTypeStore tt = typeStores.get(traitName);
                    tt.assignPosition(instance.getId());
                }
            }

            for (ITypedReferenceableInstance instance : newInstances) {
                HierarchicalTypeStore st = typeStores.get(instance.getTypeName());
                st.store((ReferenceableInstance) instance);
                for (String traitName : instance.getTraits()) {
                    HierarchicalTypeStore tt = typeStores.get(traitName);
                    tt.store((ReferenceableInstance) instance);
                }
            }
        } catch (RepositoryException re) {
            for (ITypedReferenceableInstance instance : newInstances) {
                HierarchicalTypeStore st = typeStores.get(instance.getTypeName());
                st.releaseId(instance.getId());
            }
            throw re;
        } finally {
            for (ClassType cT : classTypes) {
                HierarchicalTypeStore st = typeStores.get(cT.getName());
                st.releaseWriteLock();
            }

            for (TraitType tT : traitTypes) {
                HierarchicalTypeStore st = typeStores.get(tT.getName());
                st.releaseWriteLock();
            }
        }

        return retInstance;
    }