Examples with DiscoverInstances org.apache.atlas.repository.DiscoverInstances used on opensource projects

Example 1 with DiscoverInstances

use of org.apache.atlas.repository.DiscoverInstances in project incubator-atlas by apache.

the class MemRepository method create.

/**
 * 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.
 * 1b. Ensure that every newId has an associated Instance.
 * 2. Traverse oldIdToInstance map create newInstances : List[ITypedReferenceableInstance]
 *    - create a ITypedReferenceableInstance.
 *      replace any old References ( ids or object references) with new Ids.
 * 3. 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.
 *
 * Recovery:
 * - on each newInstance, invoke releaseId and delete on its ClassStore and Traits' Stores.
 *
 * @param i
 * @return
 * @throws org.apache.atlas.repository.RepositoryException
 */
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;
}