/**
* Abstracts Hibernate OGM from Neo4j.
*
* <p>A {@link Tuple} is saved as a {@link Node} where the columns are converted into properties of
* the node.<br>
* An {@link Association} is converted into a {@link Relationship} identified by the {@link
* AssociationKey} and the {@link RowKey}. The type of the relationship is the value returned by
* {@link AssociationKeyMetadata#getCollectionRole()}.
*
* <p>If the value of a property is set to null the property will be removed (Neo4j does not allow
* to store null values).
*
* @author Davide D'Alto <[email protected]>
*/
public class EmbeddedNeo4jDialect extends BaseNeo4jDialect {
private static final Log log = LoggerFactory.getLogger();
private final GraphDatabaseService dataBase;
private final EmbeddedNeo4jSequenceGenerator sequenceGenerator;
private Map<EntityKeyMetadata, EmbeddedNeo4jEntityQueries> entityQueries;
private Map<AssociationKeyMetadata, EmbeddedNeo4jAssociationQueries> associationQueries;
public EmbeddedNeo4jDialect(EmbeddedNeo4jDatastoreProvider provider) {
super(EmbeddedNeo4jTypeConverter.INSTANCE);
this.dataBase = provider.getDatabase();
this.sequenceGenerator = provider.getSequenceGenerator();
}
@Override
public void sessionFactoryCreated(SessionFactoryImplementor sessionFactoryImplementor) {
this.associationQueries =
Collections.unmodifiableMap(initializeAssociationQueries(sessionFactoryImplementor));
this.entityQueries =
Collections.unmodifiableMap(
initializeEntityQueries(sessionFactoryImplementor, associationQueries));
}
private Map<EntityKeyMetadata, EmbeddedNeo4jEntityQueries> initializeEntityQueries(
SessionFactoryImplementor sessionFactoryImplementor,
Map<AssociationKeyMetadata, EmbeddedNeo4jAssociationQueries> associationQueries) {
Map<EntityKeyMetadata, EmbeddedNeo4jEntityQueries> entityQueries =
initializeEntityQueries(sessionFactoryImplementor);
for (AssociationKeyMetadata associationKeyMetadata : associationQueries.keySet()) {
EntityKeyMetadata entityKeyMetadata =
associationKeyMetadata.getAssociatedEntityKeyMetadata().getEntityKeyMetadata();
if (!entityQueries.containsKey(entityKeyMetadata)) {
// Embeddables metadata
entityQueries.put(entityKeyMetadata, new EmbeddedNeo4jEntityQueries(entityKeyMetadata));
}
}
return entityQueries;
}
private Map<EntityKeyMetadata, EmbeddedNeo4jEntityQueries> initializeEntityQueries(
SessionFactoryImplementor sessionFactoryImplementor) {
Map<EntityKeyMetadata, EmbeddedNeo4jEntityQueries> queryMap =
new HashMap<EntityKeyMetadata, EmbeddedNeo4jEntityQueries>();
Collection<EntityPersister> entityPersisters =
sessionFactoryImplementor.getEntityPersisters().values();
for (EntityPersister entityPersister : entityPersisters) {
if (entityPersister instanceof OgmEntityPersister) {
OgmEntityPersister ogmEntityPersister = (OgmEntityPersister) entityPersister;
queryMap.put(
ogmEntityPersister.getEntityKeyMetadata(),
new EmbeddedNeo4jEntityQueries(ogmEntityPersister.getEntityKeyMetadata()));
}
}
return queryMap;
}
private Map<AssociationKeyMetadata, EmbeddedNeo4jAssociationQueries> initializeAssociationQueries(
SessionFactoryImplementor sessionFactoryImplementor) {
Map<AssociationKeyMetadata, EmbeddedNeo4jAssociationQueries> queryMap =
new HashMap<AssociationKeyMetadata, EmbeddedNeo4jAssociationQueries>();
Collection<CollectionPersister> collectionPersisters =
sessionFactoryImplementor.getCollectionPersisters().values();
for (CollectionPersister collectionPersister : collectionPersisters) {
if (collectionPersister instanceof OgmCollectionPersister) {
OgmCollectionPersister ogmCollectionPersister =
(OgmCollectionPersister) collectionPersister;
EntityKeyMetadata ownerEntityKeyMetadata =
((OgmEntityPersister) (ogmCollectionPersister.getOwnerEntityPersister()))
.getEntityKeyMetadata();
AssociationKeyMetadata associationKeyMetadata =
ogmCollectionPersister.getAssociationKeyMetadata();
queryMap.put(
associationKeyMetadata,
new EmbeddedNeo4jAssociationQueries(ownerEntityKeyMetadata, associationKeyMetadata));
}
}
return queryMap;
}
@Override
public Tuple getTuple(EntityKey key, OperationContext context) {
Node entityNode =
entityQueries.get(key.getMetadata()).findEntity(dataBase, key.getColumnValues());
if (entityNode == null) {
return null;
}
return new Tuple(
EmbeddedNeo4jTupleSnapshot.fromNode(
entityNode,
context.getTupleTypeContext().getAllAssociatedEntityKeyMetadata(),
context.getTupleTypeContext().getAllRoles(),
key.getMetadata()),
SnapshotType.UPDATE);
}
@Override
public List<Tuple> getTuples(EntityKey[] keys, TupleContext tupleContext) {
if (keys.length == 0) {
return Collections.emptyList();
}
// We only supports one metadata for now
EntityKeyMetadata metadata = keys[0].getMetadata();
// The result returned by the query might not be in the same order as the keys.
ResourceIterator<Node> nodes = entityQueries.get(metadata).findEntities(dataBase, keys);
try {
return tuplesResult(keys, tupleContext, nodes);
} finally {
nodes.close();
}
}
/*
* This method assumes that the nodes might not be in the same order as the keys and some keys might not have a
* matching result in the db.
*/
private List<Tuple> tuplesResult(
EntityKey[] keys, TupleContext tupleContext, ResourceIterator<Node> nodes) {
// The list is initialized with null because some keys might not have a corresponding node
Tuple[] tuples = new Tuple[keys.length];
while (nodes.hasNext()) {
Node node = nodes.next();
for (int i = 0; i < keys.length; i++) {
if (matches(node, keys[i].getColumnNames(), keys[i].getColumnValues())) {
tuples[i] =
new Tuple(
EmbeddedNeo4jTupleSnapshot.fromNode(
node,
tupleContext.getTupleTypeContext().getAllAssociatedEntityKeyMetadata(),
tupleContext.getTupleTypeContext().getAllRoles(),
keys[i].getMetadata()),
SnapshotType.UPDATE);
// We assume there are no duplicated keys
break;
}
}
}
return Arrays.asList(tuples);
}
private boolean matches(Node node, String[] properties, Object[] values) {
for (int i = 0; i < properties.length; i++) {
if (node.hasProperty(properties[i]) && !node.getProperty(properties[i]).equals(values[i])) {
return false;
} else if (!node.hasProperty(properties[i]) && values[i] != null) {
return false;
}
}
return true;
}
@Override
public Tuple createTuple(EntityKey key, OperationContext tupleContext) {
return new Tuple(
EmbeddedNeo4jTupleSnapshot.emptySnapshot(key.getMetadata()), SnapshotType.INSERT);
}
@Override
public void insertOrUpdateTuple(
EntityKey key, TuplePointer tuplePointer, TupleContext tupleContext) {
Tuple tuple = tuplePointer.getTuple();
EmbeddedNeo4jTupleSnapshot snapshot = (EmbeddedNeo4jTupleSnapshot) tuple.getSnapshot();
// insert
if (snapshot.isNew()) {
Node node = insertTuple(key, tuple);
snapshot.setNode(node);
applyTupleOperations(key, tuple, node, tuple.getOperations(), tupleContext);
GraphLogger.log("Inserted node: %1$s", node);
}
// update
else {
Node node = snapshot.getNode();
applyTupleOperations(key, tuple, node, tuple.getOperations(), tupleContext);
GraphLogger.log("Updated node: %1$s", node);
}
}
private Node insertTuple(EntityKey key, Tuple tuple) {
try {
return entityQueries.get(key.getMetadata()).insertEntity(dataBase, key.getColumnValues());
} catch (QueryExecutionException qee) {
if (CONSTRAINT_VIOLATION_CODE.equals(qee.getStatusCode())) {
Throwable cause = findRecognizableCause(qee);
if (cause instanceof UniquePropertyConstraintViolationKernelException) {
throw new TupleAlreadyExistsException(key, qee);
}
}
throw qee;
}
}
private Throwable findRecognizableCause(QueryExecutionException qee) {
Throwable cause = qee.getCause();
while (cause.getCause() != null) {
cause = cause.getCause();
}
return cause;
}
@Override
public void removeTuple(EntityKey key, TupleContext tupleContext) {
entityQueries.get(key.getMetadata()).removeEntity(dataBase, key.getColumnValues());
}
/**
* When dealing with some scenarios like, for example, a bidirectional association, OGM calls this
* method twice:
*
* <p>the first time with the information related to the owner of the association and the {@link
* RowKey}, the second time using the same {@link RowKey} but with the {@link AssociationKey}
* referring to the other side of the association.
*
* @param associatedEntityKeyMetadata
*/
private Relationship createRelationship(
AssociationKey associationKey,
Tuple associationRow,
AssociatedEntityKeyMetadata associatedEntityKeyMetadata) {
switch (associationKey.getMetadata().getAssociationKind()) {
case EMBEDDED_COLLECTION:
return createRelationshipWithEmbeddedNode(
associationKey, associationRow, associatedEntityKeyMetadata);
case ASSOCIATION:
return findOrCreateRelationshipWithEntityNode(
associationKey, associationRow, associatedEntityKeyMetadata);
default:
throw new AssertionFailure(
"Unrecognized associationKind: " + associationKey.getMetadata().getAssociationKind());
}
}
private Relationship createRelationshipWithEmbeddedNode(
AssociationKey associationKey,
Tuple associationRow,
AssociatedEntityKeyMetadata associatedEntityKeyMetadata) {
EntityKey embeddedKey = getEntityKey(associationRow, associatedEntityKeyMetadata);
Relationship relationship =
associationQueries
.get(associationKey.getMetadata())
.createRelationshipForEmbeddedAssociation(dataBase, associationKey, embeddedKey);
applyProperties(associationKey, associationRow, relationship);
return relationship;
}
private Relationship findOrCreateRelationshipWithEntityNode(
AssociationKey associationKey,
Tuple associationRow,
AssociatedEntityKeyMetadata associatedEntityKeyMetadata) {
EntityKey targetEntityKey = getEntityKey(associationRow, associatedEntityKeyMetadata);
Node targetNode =
entityQueries
.get(targetEntityKey.getMetadata())
.findEntity(dataBase, targetEntityKey.getColumnValues());
return createRelationshipWithTargetNode(associationKey, associationRow, targetNode);
}
/**
* The only properties added to a relationship are the columns representing the index of the
* association.
*/
private void applyProperties(
AssociationKey associationKey, Tuple associationRow, Relationship relationship) {
String[] indexColumns = associationKey.getMetadata().getRowKeyIndexColumnNames();
for (int i = 0; i < indexColumns.length; i++) {
String propertyName = indexColumns[i];
Object propertyValue = associationRow.get(propertyName);
relationship.setProperty(propertyName, propertyValue);
}
}
private Relationship createRelationshipWithTargetNode(
AssociationKey associationKey, Tuple associationRow, Node targetNode) {
EntityKey entityKey = associationKey.getEntityKey();
Node ownerNode =
entityQueries
.get(entityKey.getMetadata())
.findEntity(dataBase, entityKey.getColumnValues());
Relationship relationship =
ownerNode.createRelationshipTo(
targetNode, withName(associationKey.getMetadata().getCollectionRole()));
applyProperties(associationKey, associationRow, relationship);
return relationship;
}
@Override
public Association getAssociation(
AssociationKey associationKey, AssociationContext associationContext) {
EntityKey entityKey = associationKey.getEntityKey();
Node entityNode =
entityQueries
.get(entityKey.getMetadata())
.findEntity(dataBase, entityKey.getColumnValues());
GraphLogger.log("Found owner node: %1$s", entityNode);
if (entityNode == null) {
return null;
}
Map<RowKey, Tuple> tuples = createAssociationMap(associationKey, associationContext, entityKey);
return new Association(new EmbeddedNeo4jAssociationSnapshot(tuples));
}
private Map<RowKey, Tuple> createAssociationMap(
AssociationKey associationKey, AssociationContext associationContext, EntityKey entityKey) {
String relationshipType = associationContext.getAssociationTypeContext().getRoleOnMainSide();
ResourceIterator<Relationship> relationships =
entityQueries
.get(entityKey.getMetadata())
.findAssociation(dataBase, entityKey.getColumnValues(), relationshipType);
Map<RowKey, Tuple> tuples = new HashMap<RowKey, Tuple>();
try {
while (relationships.hasNext()) {
Relationship relationship = relationships.next();
AssociatedEntityKeyMetadata associatedEntityKeyMetadata =
associationContext.getAssociationTypeContext().getAssociatedEntityKeyMetadata();
EmbeddedNeo4jTupleAssociationSnapshot snapshot =
new EmbeddedNeo4jTupleAssociationSnapshot(
relationship, associationKey, associatedEntityKeyMetadata);
RowKey rowKey = convert(associationKey, snapshot);
tuples.put(rowKey, new Tuple(snapshot, SnapshotType.UPDATE));
}
return tuples;
} finally {
relationships.close();
}
}
@Override
public void insertOrUpdateAssociation(
AssociationKey key, Association association, AssociationContext associationContext) {
// If this is the inverse side of a bi-directional association, we don't create a relationship
// for this; this
// will happen when updating the main side
if (key.getMetadata().isInverse()) {
return;
}
for (AssociationOperation action : association.getOperations()) {
applyAssociationOperation(association, key, action, associationContext);
}
}
@Override
public void removeAssociation(AssociationKey key, AssociationContext associationContext) {
// If this is the inverse side of a bi-directional association, we don't manage the relationship
// from this side
if (key.getMetadata().isInverse()) {
return;
}
associationQueries.get(key.getMetadata()).removeAssociation(dataBase, key);
}
private void applyAssociationOperation(
Association association,
AssociationKey key,
AssociationOperation operation,
AssociationContext associationContext) {
switch (operation.getType()) {
case CLEAR:
removeAssociation(key, associationContext);
break;
case PUT:
putAssociationOperation(
association,
key,
operation,
associationContext.getAssociationTypeContext().getAssociatedEntityKeyMetadata());
break;
case REMOVE:
removeAssociationOperation(
association,
key,
operation,
associationContext.getAssociationTypeContext().getAssociatedEntityKeyMetadata());
break;
}
}
private void putAssociationOperation(
Association association,
AssociationKey associationKey,
AssociationOperation action,
AssociatedEntityKeyMetadata associatedEntityKeyMetadata) {
Relationship relationship =
associationQueries
.get(associationKey.getMetadata())
.findRelationship(dataBase, associationKey, action.getKey());
if (relationship != null) {
for (String relationshipProperty : associationKey.getMetadata().getRowKeyIndexColumnNames()) {
relationship.setProperty(relationshipProperty, action.getValue().get(relationshipProperty));
}
for (String column :
associationKey
.getMetadata()
.getColumnsWithoutKeyColumns(action.getValue().getColumnNames())) {
if (!isRowKeyColumn(associationKey.getMetadata(), column)) {
relationship.getEndNode().setProperty(column, action.getValue().get(column));
}
}
GraphLogger.log("Updated relationship: %1$s", relationship);
} else {
relationship =
createRelationship(associationKey, action.getValue(), associatedEntityKeyMetadata);
GraphLogger.log("Created relationship: %1$s", relationship);
}
}
// TODO replace with method provided by OGM-1035
private boolean isRowKeyColumn(AssociationKeyMetadata metadata, String column) {
for (String rowKeyColumn : metadata.getRowKeyColumnNames()) {
if (rowKeyColumn.equals(column)) {
return true;
}
}
return false;
}
private void removeAssociationOperation(
Association association,
AssociationKey associationKey,
AssociationOperation action,
AssociatedEntityKeyMetadata associatedEntityKeyMetadata) {
associationQueries
.get(associationKey.getMetadata())
.removeAssociationRow(dataBase, associationKey, action.getKey());
}
private void applyTupleOperations(
EntityKey entityKey,
Tuple tuple,
Node node,
Set<TupleOperation> operations,
TupleContext tupleContext) {
Set<String> processedAssociationRoles = new HashSet<String>();
for (TupleOperation operation : operations) {
applyOperation(entityKey, tuple, node, operation, tupleContext, processedAssociationRoles);
}
}
private void applyOperation(
EntityKey entityKey,
Tuple tuple,
Node node,
TupleOperation operation,
TupleContext tupleContext,
Set<String> processedAssociationRoles) {
switch (operation.getType()) {
case PUT:
putTupleOperation(
entityKey, tuple, node, operation, tupleContext, processedAssociationRoles);
break;
case PUT_NULL:
case REMOVE:
removeTupleOperation(entityKey, node, operation, tupleContext, processedAssociationRoles);
break;
}
}
private void removeTupleOperation(
EntityKey entityKey,
Node node,
TupleOperation operation,
TupleContext tupleContext,
Set<String> processedAssociationRoles) {
if (!tupleContext.getTupleTypeContext().isPartOfAssociation(operation.getColumn())) {
if (isPartOfRegularEmbedded(entityKey.getColumnNames(), operation.getColumn())) {
// Embedded node
String[] split = split(operation.getColumn());
removePropertyForEmbedded(node, split, 0);
} else if (node.hasProperty(operation.getColumn())) {
node.removeProperty(operation.getColumn());
}
}
// if the column represents a to-one association, remove the relationship
else {
String associationRole = tupleContext.getTupleTypeContext().getRole(operation.getColumn());
if (!processedAssociationRoles.contains(associationRole)) {
Iterator<Relationship> relationships =
node.getRelationships(withName(associationRole)).iterator();
if (relationships.hasNext()) {
relationships.next().delete();
}
}
}
}
/*
* It will remove a property from an embedded node if it exists.
* After deleting the property, if the node does not have any more properties and relationships (except for an incoming one),
* it will delete the embedded node as well.
*/
private void removePropertyForEmbedded(Node embeddedNode, String[] embeddedColumnSplit, int i) {
if (i == embeddedColumnSplit.length - 1) {
// Property
String property = embeddedColumnSplit[embeddedColumnSplit.length - 1];
if (embeddedNode.hasProperty(property)) {
embeddedNode.removeProperty(property);
}
} else {
Iterator<Relationship> iterator =
embeddedNode
.getRelationships(Direction.OUTGOING, withName(embeddedColumnSplit[i]))
.iterator();
if (iterator.hasNext()) {
removePropertyForEmbedded(iterator.next().getEndNode(), embeddedColumnSplit, i + 1);
}
}
if (!embeddedNode.getPropertyKeys().iterator().hasNext()) {
// Node without properties
Iterator<Relationship> iterator = embeddedNode.getRelationships().iterator();
if (iterator.hasNext()) {
Relationship relationship = iterator.next();
if (!iterator.hasNext()) {
// Node with only one relationship and no properties,
// we can remove it:
// It means we have removed all the properties from the embedded node
// and it is NOT an intermediate node like
// (entity) --> (embedded1) --> (embedded2)
relationship.delete();
embeddedNode.delete();
}
}
}
}
private void putTupleOperation(
EntityKey entityKey,
Tuple tuple,
Node node,
TupleOperation operation,
TupleContext tupleContext,
Set<String> processedAssociationRoles) {
if (tupleContext.getTupleTypeContext().isPartOfAssociation(operation.getColumn())) {
// the column represents a to-one association, map it as relationship
putOneToOneAssociation(tuple, node, operation, tupleContext, processedAssociationRoles);
} else if (isPartOfRegularEmbedded(
entityKey.getMetadata().getColumnNames(), operation.getColumn())) {
entityQueries
.get(entityKey.getMetadata())
.updateEmbeddedColumn(
dataBase, entityKey.getColumnValues(), operation.getColumn(), operation.getValue());
} else {
putProperty(entityKey, node, operation);
}
}
private void putProperty(EntityKey entityKey, Node node, TupleOperation operation) {
try {
node.setProperty(operation.getColumn(), operation.getValue());
} catch (ConstraintViolationException e) {
String message = e.getMessage();
if (message.contains("already exists")) {
throw log.mustNotInsertSameEntityTwice(String.valueOf(operation), e);
} else {
throw log.constraintViolation(entityKey, String.valueOf(operation), e);
}
}
}
private void putOneToOneAssociation(
Tuple tuple,
Node node,
TupleOperation operation,
TupleContext tupleContext,
Set<String> processedAssociationRoles) {
String associationRole = tupleContext.getTupleTypeContext().getRole(operation.getColumn());
if (!processedAssociationRoles.contains(associationRole)) {
processedAssociationRoles.add(associationRole);
EntityKey targetKey =
getEntityKey(
tuple,
tupleContext
.getTupleTypeContext()
.getAssociatedEntityKeyMetadata(operation.getColumn()));
// delete the previous relationship if there is one; for a to-one association, the
// relationship won't have any
// properties, so the type is uniquely identifying it
Iterator<Relationship> relationships =
node.getRelationships(withName(associationRole)).iterator();
if (relationships.hasNext()) {
relationships.next().delete();
}
// create a new relationship
Node targetNode =
entityQueries
.get(targetKey.getMetadata())
.findEntity(dataBase, targetKey.getColumnValues());
node.createRelationshipTo(targetNode, withName(associationRole));
}
}
@Override
public void forEachTuple(
ModelConsumer consumer,
TupleTypeContext tupleTypeContext,
EntityKeyMetadata entityKeyMetadata) {
ResourceIterator<Node> queryNodes = entityQueries.get(entityKeyMetadata).findEntities(dataBase);
try {
while (queryNodes.hasNext()) {
Node next = queryNodes.next();
Tuple tuple =
new Tuple(
EmbeddedNeo4jTupleSnapshot.fromNode(
next,
tupleTypeContext.getAllAssociatedEntityKeyMetadata(),
tupleTypeContext.getAllRoles(),
entityKeyMetadata),
SnapshotType.UPDATE);
consumer.consume(tuple);
}
} finally {
queryNodes.close();
}
}
@Override
public Number nextValue(NextValueRequest request) {
return sequenceGenerator.nextValue(request);
}
@Override
public ClosableIterator<Tuple> executeBackendQuery(
BackendQuery<String> backendQuery,
QueryParameters queryParameters,
TupleContext tupleContext) {
Map<String, Object> parameters = getParameters(queryParameters);
String nativeQuery = buildNativeQuery(backendQuery, queryParameters);
try {
Result result = dataBase.execute(nativeQuery, parameters);
EntityMetadataInformation entityMetadataInformation =
backendQuery.getSingleEntityMetadataInformationOrNull();
if (entityMetadataInformation != null) {
return new EmbeddedNeo4jNodesTupleIterator(
result, entityMetadataInformation.getEntityKeyMetadata(), tupleContext);
}
return new EmbeddedNeo4jMapsTupleIterator(result);
} catch (QueryExecutionException qe) {
throw log.nativeQueryException(qe.getStatusCode(), qe.getMessage(), qe);
}
}
@Override
public int executeBackendUpdateQuery(
BackendQuery<String> backendQuery,
QueryParameters queryParameters,
TupleContext tupleContext) {
Map<String, Object> parameters = getParameters(queryParameters);
String nativeQuery = buildNativeQuery(backendQuery, queryParameters);
try {
Result result = dataBase.execute(nativeQuery, parameters);
return summaryUpdates(result);
} catch (QueryExecutionException qe) {
throw log.nativeQueryException(qe.getStatusCode(), qe.getMessage(), qe);
}
}
private int summaryUpdates(Result result) {
int updates = 0;
updates += result.getQueryStatistics().getConstraintsAdded();
updates += result.getQueryStatistics().getConstraintsRemoved();
updates += result.getQueryStatistics().getNodesCreated();
updates += result.getQueryStatistics().getNodesDeleted();
updates += result.getQueryStatistics().getRelationshipsCreated();
updates += result.getQueryStatistics().getRelationshipsDeleted();
updates += result.getQueryStatistics().getLabelsAdded();
updates += result.getQueryStatistics().getLabelsRemoved();
updates += result.getQueryStatistics().getPropertiesSet();
return updates;
}
@Override
public String parseNativeQuery(String nativeQuery) {
// We return given Cypher queries as they are; Currently there is no API for validating Cypher
// queries without
// actually executing them (see https://github.com/neo4j/neo4j/issues/2766)
return nativeQuery;
}
}
/**
* Abstracts Hibernate OGM from Neo4j.
*
* <p>A {@link Tuple} is saved as a {@link Node} where the columns are converted into properties of
* the node.<br>
* An {@link Association} is converted into a {@link Relationship} identified by the {@link
* AssociationKey} and the {@link RowKey}. The type of the relationship is the value returned by
* {@link AssociationKeyMetadata#getCollectionRole()}.
*
* <p>If the value of a property is set to null the property will be removed (Neo4j does not allow
* to store null values).
*
* @author Davide D'Alto <[email protected]>
*/
public class Neo4jDialect extends BaseGridDialect
implements MultigetGridDialect,
QueryableGridDialect<String>,
SessionFactoryLifecycleAwareDialect {
public static final String CONSTRAINT_VIOLATION_CODE =
"Neo.ClientError.Schema.ConstraintViolation";
private static final Log log = LoggerFactory.getLogger();
private final Neo4jSequenceGenerator neo4jSequenceGenerator;
private final GraphDatabaseService dataBase;
private Map<EntityKeyMetadata, Neo4jEntityQueries> entityQueries;
private Map<AssociationKeyMetadata, Neo4jAssociationQueries> associationQueries;
public Neo4jDialect(Neo4jDatastoreProvider provider) {
dataBase = provider.getDataBase();
this.neo4jSequenceGenerator = provider.getSequenceGenerator();
}
@Override
public void sessionFactoryCreated(SessionFactoryImplementor sessionFactoryImplementor) {
this.associationQueries =
Collections.unmodifiableMap(initializeAssociationQueries(sessionFactoryImplementor));
this.entityQueries =
Collections.unmodifiableMap(
initializeEntityQueries(sessionFactoryImplementor, associationQueries));
}
private Map<EntityKeyMetadata, Neo4jEntityQueries> initializeEntityQueries(
SessionFactoryImplementor sessionFactoryImplementor,
Map<AssociationKeyMetadata, Neo4jAssociationQueries> associationQueries) {
Map<EntityKeyMetadata, Neo4jEntityQueries> entityQueries =
initializeEntityQueries(sessionFactoryImplementor);
for (AssociationKeyMetadata associationKeyMetadata : associationQueries.keySet()) {
EntityKeyMetadata entityKeyMetadata =
associationKeyMetadata.getAssociatedEntityKeyMetadata().getEntityKeyMetadata();
if (!entityQueries.containsKey(entityKeyMetadata)) {
// Embeddables metadata
entityQueries.put(entityKeyMetadata, new Neo4jEntityQueries(entityKeyMetadata));
}
}
return entityQueries;
}
private Map<EntityKeyMetadata, Neo4jEntityQueries> initializeEntityQueries(
SessionFactoryImplementor sessionFactoryImplementor) {
Map<EntityKeyMetadata, Neo4jEntityQueries> queryMap =
new HashMap<EntityKeyMetadata, Neo4jEntityQueries>();
Collection<EntityPersister> entityPersisters =
sessionFactoryImplementor.getEntityPersisters().values();
for (EntityPersister entityPersister : entityPersisters) {
if (entityPersister instanceof OgmEntityPersister) {
OgmEntityPersister ogmEntityPersister = (OgmEntityPersister) entityPersister;
queryMap.put(
ogmEntityPersister.getEntityKeyMetadata(),
new Neo4jEntityQueries(ogmEntityPersister.getEntityKeyMetadata()));
}
}
return queryMap;
}
private Map<AssociationKeyMetadata, Neo4jAssociationQueries> initializeAssociationQueries(
SessionFactoryImplementor sessionFactoryImplementor) {
Map<AssociationKeyMetadata, Neo4jAssociationQueries> queryMap =
new HashMap<AssociationKeyMetadata, Neo4jAssociationQueries>();
Collection<CollectionPersister> collectionPersisters =
sessionFactoryImplementor.getCollectionPersisters().values();
for (CollectionPersister collectionPersister : collectionPersisters) {
if (collectionPersister instanceof OgmCollectionPersister) {
OgmCollectionPersister ogmCollectionPersister =
(OgmCollectionPersister) collectionPersister;
EntityKeyMetadata ownerEntityKeyMetadata =
((OgmEntityPersister) (ogmCollectionPersister.getOwnerEntityPersister()))
.getEntityKeyMetadata();
AssociationKeyMetadata associationKeyMetadata =
ogmCollectionPersister.getAssociationKeyMetadata();
queryMap.put(
associationKeyMetadata,
new Neo4jAssociationQueries(ownerEntityKeyMetadata, associationKeyMetadata));
}
}
return queryMap;
}
@Override
public Tuple getTuple(EntityKey key, TupleContext context) {
Node entityNode =
entityQueries.get(key.getMetadata()).findEntity(dataBase, key.getColumnValues());
if (entityNode == null) {
return null;
}
return new Tuple(
new Neo4jTupleSnapshot(
entityNode,
context.getAllAssociatedEntityKeyMetadata(),
context.getAllRoles(),
key.getMetadata()));
}
@Override
public List<Tuple> getTuples(EntityKey[] keys, TupleContext tupleContext) {
if (keys.length == 0) {
return Collections.emptyList();
}
// We only supports one metadata for now
EntityKeyMetadata metadata = keys[0].getMetadata();
// The result returned by the query might not be in the same order as the keys.
ResourceIterator<Node> nodes = entityQueries.get(metadata).findEntities(dataBase, keys);
try {
return tuplesResult(keys, tupleContext, nodes);
} finally {
nodes.close();
}
}
/*
* This method assumes that the nodes might not be in the same order as the keys and some keys might not have a
* matching result in the db.
*/
private List<Tuple> tuplesResult(
EntityKey[] keys, TupleContext tupleContext, ResourceIterator<Node> nodes) {
// The list is initialized with null because some keys might not have a corresponding node
Tuple[] tuples = new Tuple[keys.length];
while (nodes.hasNext()) {
Node node = nodes.next();
for (int i = 0; i < keys.length; i++) {
if (matches(node, keys[i].getColumnNames(), keys[i].getColumnValues())) {
tuples[i] =
new Tuple(
new Neo4jTupleSnapshot(
node,
tupleContext.getAllAssociatedEntityKeyMetadata(),
tupleContext.getAllRoles(),
keys[i].getMetadata()));
// We assume there are no duplicated keys
break;
}
}
}
return Arrays.asList(tuples);
}
private boolean matches(Node node, String[] properties, Object[] values) {
for (int i = 0; i < properties.length; i++) {
if (node.hasProperty(properties[i]) && !node.getProperty(properties[i]).equals(values[i])) {
return false;
} else if (!node.hasProperty(properties[i]) && values[i] != null) {
return false;
}
}
return true;
}
@Override
public Tuple createTuple(EntityKey key, TupleContext tupleContext) {
return new Tuple(new Neo4jTupleSnapshot(key.getMetadata()));
}
@Override
public void insertOrUpdateTuple(EntityKey key, Tuple tuple, TupleContext tupleContext) {
Neo4jTupleSnapshot snapshot = (Neo4jTupleSnapshot) tuple.getSnapshot();
// insert
if (snapshot.isNew()) {
Node node = insertTuple(key, tuple);
snapshot.setNode(node);
applyTupleOperations(key, tuple, node, tuple.getOperations(), tupleContext);
GraphLogger.log("Inserted node: %1$s", node);
}
// update
else {
Node node = snapshot.getNode();
applyTupleOperations(key, tuple, node, tuple.getOperations(), tupleContext);
GraphLogger.log("Updated node: %1$s", node);
}
}
private Node insertTuple(EntityKey key, Tuple tuple) {
try {
return entityQueries.get(key.getMetadata()).insertEntity(dataBase, key.getColumnValues());
} catch (QueryExecutionException qee) {
if (CONSTRAINT_VIOLATION_CODE.equals(qee.getStatusCode())) {
Throwable cause = findRecognizableCause(qee);
if (cause instanceof UniquePropertyConstraintViolationKernelException) {
throw new TupleAlreadyExistsException(key.getMetadata(), tuple, qee);
}
}
throw qee;
}
}
private Throwable findRecognizableCause(QueryExecutionException qee) {
Throwable cause = qee.getCause();
while (cause.getCause() != null) {
cause = cause.getCause();
}
return cause;
}
@Override
public void removeTuple(EntityKey key, TupleContext tupleContext) {
entityQueries.get(key.getMetadata()).removeEntity(dataBase, key.getColumnValues());
}
/**
* When dealing with some scenarios like, for example, a bidirectional association, OGM calls this
* method twice:
*
* <p>the first time with the information related to the owner of the association and the {@link
* RowKey}, the second time using the same {@link RowKey} but with the {@link AssociationKey}
* referring to the other side of the association.
*
* @param associatedEntityKeyMetadata
*/
private Relationship createRelationship(
AssociationKey associationKey,
Tuple associationRow,
AssociatedEntityKeyMetadata associatedEntityKeyMetadata) {
switch (associationKey.getMetadata().getAssociationKind()) {
case EMBEDDED_COLLECTION:
return createRelationshipWithEmbeddedNode(
associationKey, associationRow, associatedEntityKeyMetadata);
case ASSOCIATION:
return findOrCreateRelationshipWithEntityNode(
associationKey, associationRow, associatedEntityKeyMetadata);
default:
throw new AssertionFailure(
"Unrecognized associationKind: " + associationKey.getMetadata().getAssociationKind());
}
}
private Relationship createRelationshipWithEmbeddedNode(
AssociationKey associationKey,
Tuple associationRow,
AssociatedEntityKeyMetadata associatedEntityKeyMetadata) {
EntityKey embeddedKey = getEntityKey(associationRow, associatedEntityKeyMetadata);
Relationship relationship =
associationQueries
.get(associationKey.getMetadata())
.createRelationshipForEmbeddedAssociation(dataBase, associationKey, embeddedKey);
applyProperties(associationKey, associationRow, relationship);
return relationship;
}
private Relationship findOrCreateRelationshipWithEntityNode(
AssociationKey associationKey,
Tuple associationRow,
AssociatedEntityKeyMetadata associatedEntityKeyMetadata) {
EntityKey targetEntityKey = getEntityKey(associationRow, associatedEntityKeyMetadata);
Node targetNode =
entityQueries
.get(targetEntityKey.getMetadata())
.findEntity(dataBase, targetEntityKey.getColumnValues());
return createRelationshipWithTargetNode(associationKey, associationRow, targetNode);
}
/**
* The only properties added to a relationship are the columns representing the index of the
* association.
*/
private void applyProperties(
AssociationKey associationKey, Tuple associationRow, Relationship relationship) {
String[] indexColumns = associationKey.getMetadata().getRowKeyIndexColumnNames();
for (int i = 0; i < indexColumns.length; i++) {
String propertyName = indexColumns[i];
Object propertyValue = associationRow.get(propertyName);
relationship.setProperty(propertyName, propertyValue);
}
}
private Relationship createRelationshipWithTargetNode(
AssociationKey associationKey, Tuple associationRow, Node targetNode) {
EntityKey entityKey = associationKey.getEntityKey();
Node ownerNode =
entityQueries
.get(entityKey.getMetadata())
.findEntity(dataBase, entityKey.getColumnValues());
Relationship relationship =
ownerNode.createRelationshipTo(
targetNode, withName(associationKey.getMetadata().getCollectionRole()));
applyProperties(associationKey, associationRow, relationship);
return relationship;
}
@Override
public Association getAssociation(
AssociationKey associationKey, AssociationContext associationContext) {
EntityKey entityKey = associationKey.getEntityKey();
Node entityNode =
entityQueries
.get(entityKey.getMetadata())
.findEntity(dataBase, entityKey.getColumnValues());
GraphLogger.log("Found owner node: %1$s", entityNode);
if (entityNode == null) {
return null;
}
Map<RowKey, Tuple> tuples = createAssociationMap(associationKey, associationContext, entityKey);
return new Association(new Neo4jAssociationSnapshot(tuples));
}
private Map<RowKey, Tuple> createAssociationMap(
AssociationKey associationKey, AssociationContext associationContext, EntityKey entityKey) {
String relationshipType = associationContext.getAssociationTypeContext().getRoleOnMainSide();
ResourceIterator<Relationship> relationships =
entityQueries
.get(entityKey.getMetadata())
.findAssociation(dataBase, entityKey.getColumnValues(), relationshipType);
Map<RowKey, Tuple> tuples = new HashMap<RowKey, Tuple>();
try {
while (relationships.hasNext()) {
Relationship relationship = relationships.next();
AssociatedEntityKeyMetadata associatedEntityKeyMetadata =
associationContext.getAssociationTypeContext().getAssociatedEntityKeyMetadata();
Neo4jTupleAssociationSnapshot snapshot =
new Neo4jTupleAssociationSnapshot(
relationship, associationKey, associatedEntityKeyMetadata);
RowKey rowKey = convert(associationKey, snapshot);
tuples.put(rowKey, new Tuple(snapshot));
}
return tuples;
} finally {
relationships.close();
}
}
private RowKey convert(AssociationKey associationKey, Neo4jTupleAssociationSnapshot snapshot) {
String[] columnNames = associationKey.getMetadata().getRowKeyColumnNames();
Object[] values = new Object[columnNames.length];
for (int i = 0; i < columnNames.length; i++) {
values[i] = snapshot.get(columnNames[i]);
}
return new RowKey(columnNames, values);
}
@Override
public Association createAssociation(
AssociationKey associationKey, AssociationContext associationContext) {
return new Association();
}
@Override
public void insertOrUpdateAssociation(
AssociationKey key, Association association, AssociationContext associationContext) {
// If this is the inverse side of a bi-directional association, we don't create a relationship
// for this; this
// will happen when updating the main side
if (key.getMetadata().isInverse()) {
return;
}
for (AssociationOperation action : association.getOperations()) {
applyAssociationOperation(association, key, action, associationContext);
}
}
@Override
public boolean isStoredInEntityStructure(
AssociationKeyMetadata associationKeyMetadata,
AssociationTypeContext associationTypeContext) {
return false;
}
@Override
public Number nextValue(NextValueRequest request) {
return neo4jSequenceGenerator.nextValue(
request.getKey(), request.getIncrement(), request.getInitialValue());
}
@Override
public boolean supportsSequences() {
return true;
}
@Override
public GridType overrideType(Type type) {
return Neo4jTypeConverter.INSTANCE.convert(type);
}
@Override
public void removeAssociation(AssociationKey key, AssociationContext associationContext) {
// If this is the inverse side of a bi-directional association, we don't manage the relationship
// from this side
if (key.getMetadata().isInverse()) {
return;
}
associationQueries.get(key.getMetadata()).removeAssociation(dataBase, key);
}
private void applyAssociationOperation(
Association association,
AssociationKey key,
AssociationOperation operation,
AssociationContext associationContext) {
switch (operation.getType()) {
case CLEAR:
removeAssociation(key, associationContext);
break;
case PUT:
putAssociationOperation(
association,
key,
operation,
associationContext.getAssociationTypeContext().getAssociatedEntityKeyMetadata());
break;
case REMOVE:
removeAssociationOperation(
association,
key,
operation,
associationContext.getAssociationTypeContext().getAssociatedEntityKeyMetadata());
break;
}
}
private void putAssociationOperation(
Association association,
AssociationKey associationKey,
AssociationOperation action,
AssociatedEntityKeyMetadata associatedEntityKeyMetadata) {
Relationship relationship =
associationQueries
.get(associationKey.getMetadata())
.findRelationship(dataBase, associationKey, action.getKey());
if (relationship != null) {
for (String relationshipProperty : associationKey.getMetadata().getRowKeyIndexColumnNames()) {
relationship.setProperty(relationshipProperty, action.getValue().get(relationshipProperty));
}
GraphLogger.log("Updated relationship: %1$s", relationship);
} else {
relationship =
createRelationship(associationKey, action.getValue(), associatedEntityKeyMetadata);
GraphLogger.log("Created relationship: %1$s", relationship);
}
}
private void removeAssociationOperation(
Association association,
AssociationKey associationKey,
AssociationOperation action,
AssociatedEntityKeyMetadata associatedEntityKeyMetadata) {
associationQueries
.get(associationKey.getMetadata())
.removeAssociationRow(dataBase, associationKey, action.getKey());
}
private void applyTupleOperations(
EntityKey entityKey,
Tuple tuple,
Node node,
Set<TupleOperation> operations,
TupleContext tupleContext) {
Set<String> processedAssociationRoles = new HashSet<String>();
for (TupleOperation operation : operations) {
applyOperation(entityKey, tuple, node, operation, tupleContext, processedAssociationRoles);
}
}
private void applyOperation(
EntityKey entityKey,
Tuple tuple,
Node node,
TupleOperation operation,
TupleContext tupleContext,
Set<String> processedAssociationRoles) {
switch (operation.getType()) {
case PUT:
putTupleOperation(
entityKey, tuple, node, operation, tupleContext, processedAssociationRoles);
break;
case PUT_NULL:
case REMOVE:
removeTupleOperation(entityKey, node, operation, tupleContext, processedAssociationRoles);
break;
}
}
private void removeTupleOperation(
EntityKey entityKey,
Node node,
TupleOperation operation,
TupleContext tupleContext,
Set<String> processedAssociationRoles) {
if (!tupleContext.isPartOfAssociation(operation.getColumn())) {
if (isPartOfRegularEmbedded(entityKey.getColumnNames(), operation.getColumn())) {
// Embedded node
String[] split = split(operation.getColumn());
removePropertyForEmbedded(node, split, 0);
} else if (node.hasProperty(operation.getColumn())) {
node.removeProperty(operation.getColumn());
}
}
// if the column represents a to-one association, remove the relationship
else {
String associationRole = tupleContext.getRole(operation.getColumn());
if (!processedAssociationRoles.contains(associationRole)) {
Iterator<Relationship> relationships =
node.getRelationships(withName(associationRole)).iterator();
if (relationships.hasNext()) {
relationships.next().delete();
}
}
}
}
/*
* It will remove a property from an embedded node if it exists.
* After deleting the property, if the node does not have any more properties and relationships (except for an incoming one),
* it will delete the embedded node as well.
*/
private void removePropertyForEmbedded(Node embeddedNode, String[] embeddedColumnSplit, int i) {
if (i == embeddedColumnSplit.length - 1) {
// Property
String property = embeddedColumnSplit[embeddedColumnSplit.length - 1];
if (embeddedNode.hasProperty(property)) {
embeddedNode.removeProperty(property);
}
} else {
Iterator<Relationship> iterator =
embeddedNode
.getRelationships(Direction.OUTGOING, withName(embeddedColumnSplit[i]))
.iterator();
if (iterator.hasNext()) {
removePropertyForEmbedded(iterator.next().getEndNode(), embeddedColumnSplit, i + 1);
}
}
if (!embeddedNode.getPropertyKeys().iterator().hasNext()) {
// Node without properties
Iterator<Relationship> iterator = embeddedNode.getRelationships().iterator();
if (iterator.hasNext()) {
Relationship relationship = iterator.next();
if (!iterator.hasNext()) {
// Node with only one relationship and no properties,
// we can remove it:
// It means we have removed all the properties from the embedded node
// and it is NOT an intermediate node like
// (entity) --> (embedded1) --> (embedded2)
relationship.delete();
embeddedNode.delete();
}
}
}
}
private void putTupleOperation(
EntityKey entityKey,
Tuple tuple,
Node node,
TupleOperation operation,
TupleContext tupleContext,
Set<String> processedAssociationRoles) {
if (tupleContext.isPartOfAssociation(operation.getColumn())) {
// the column represents a to-one association, map it as relationship
putOneToOneAssociation(tuple, node, operation, tupleContext, processedAssociationRoles);
} else if (isPartOfRegularEmbedded(
entityKey.getMetadata().getColumnNames(), operation.getColumn())) {
entityQueries
.get(entityKey.getMetadata())
.updateEmbeddedColumn(
dataBase, entityKey.getColumnValues(), operation.getColumn(), operation.getValue());
} else {
putProperty(entityKey, node, operation);
}
}
/**
* A regular embedded is an element that it is embedded but it is not a key or a collection.
*
* @param keyColumnNames the column names representing the identifier of the entity
* @param column the column we want to check
* @return {@code true} if the column represent an attribute of a regular embedded element, {@code
* false} otherwise
*/
public static boolean isPartOfRegularEmbedded(String[] keyColumnNames, String column) {
return isPartOfEmbedded(column) && !ArrayHelper.contains(keyColumnNames, column);
}
private void putProperty(EntityKey entityKey, Node node, TupleOperation operation) {
try {
node.setProperty(operation.getColumn(), operation.getValue());
} catch (ConstraintViolationException e) {
throw log.constraintViolation(entityKey, operation, e);
}
}
private void putOneToOneAssociation(
Tuple tuple,
Node node,
TupleOperation operation,
TupleContext tupleContext,
Set<String> processedAssociationRoles) {
String associationRole = tupleContext.getRole(operation.getColumn());
if (!processedAssociationRoles.contains(associationRole)) {
processedAssociationRoles.add(associationRole);
EntityKey targetKey =
getEntityKey(tuple, tupleContext.getAssociatedEntityKeyMetadata(operation.getColumn()));
// delete the previous relationship if there is one; for a to-one association, the
// relationship won't have any
// properties, so the type is uniquely identifying it
Iterator<Relationship> relationships =
node.getRelationships(withName(associationRole)).iterator();
if (relationships.hasNext()) {
relationships.next().delete();
}
// create a new relationship
Node targetNode =
entityQueries
.get(targetKey.getMetadata())
.findEntity(dataBase, targetKey.getColumnValues());
node.createRelationshipTo(targetNode, withName(associationRole));
}
}
@Override
public void forEachTuple(ModelConsumer consumer, EntityKeyMetadata... entityKeyMetadatas) {
for (EntityKeyMetadata entityKeyMetadata : entityKeyMetadatas) {
ResourceIterator<Node> queryNodes =
entityQueries.get(entityKeyMetadata).findEntities(dataBase);
try {
while (queryNodes.hasNext()) {
Node next = queryNodes.next();
Tuple tuple = new Tuple(new Neo4jTupleSnapshot(next, entityKeyMetadata));
consumer.consume(tuple);
}
} finally {
queryNodes.close();
}
}
}
@Override
public ClosableIterator<Tuple> executeBackendQuery(
BackendQuery<String> backendQuery, QueryParameters queryParameters) {
Map<String, Object> parameters = getNamedParameterValuesConvertedByGridType(queryParameters);
String nativeQuery = buildNativeQuery(backendQuery, queryParameters);
Result result = dataBase.execute(nativeQuery, parameters);
if (backendQuery.getSingleEntityKeyMetadataOrNull() != null) {
return new NodesTupleIterator(result, backendQuery.getSingleEntityKeyMetadataOrNull());
}
return new MapsTupleIterator(result);
}
@Override
public int executeBackendUpdateQuery(
BackendQuery<String> query, QueryParameters queryParameters) {
// TODO implement.
// org.hibernate.ogm.datastore.mongodb.MongoDBDialect.executeBackendUpdateQuery(BackendQuery<MongoDBQueryDescriptor>, QueryParameters) might be helpful as a reference.
throw new UnsupportedOperationException("Not yet implemented.");
}
@Override
public String parseNativeQuery(String nativeQuery) {
// We return given Cypher queries as they are; Currently there is no API for validating Cypher
// queries without
// actually executing them (see https://github.com/neo4j/neo4j/issues/2766)
return nativeQuery;
}
private String buildNativeQuery(
BackendQuery<String> customQuery, QueryParameters queryParameters) {
StringBuilder nativeQuery = new StringBuilder(customQuery.getQuery());
applyFirstRow(queryParameters, nativeQuery);
applyMaxRows(queryParameters, nativeQuery);
return nativeQuery.toString();
}
private void applyFirstRow(QueryParameters queryParameters, StringBuilder nativeQuery) {
Integer firstRow = queryParameters.getRowSelection().getFirstRow();
if (firstRow != null) {
skip(nativeQuery, firstRow);
}
}
private void applyMaxRows(QueryParameters queryParameters, StringBuilder nativeQuery) {
Integer maxRows = queryParameters.getRowSelection().getMaxRows();
if (maxRows != null) {
limit(nativeQuery, maxRows);
}
}
/**
* Returns a map with the named parameter values from the given parameters object, converted by
* the {@link GridType} corresponding to each parameter type.
*/
private Map<String, Object> getNamedParameterValuesConvertedByGridType(
QueryParameters queryParameters) {
Map<String, Object> parameterValues =
new HashMap<String, Object>(queryParameters.getNamedParameters().size());
Tuple dummy = new Tuple();
for (Entry<String, TypedGridValue> parameter :
queryParameters.getNamedParameters().entrySet()) {
parameter
.getValue()
.getType()
.nullSafeSet(
dummy, parameter.getValue().getValue(), new String[] {parameter.getKey()}, null);
parameterValues.put(parameter.getKey(), dummy.get(parameter.getKey()));
}
return parameterValues;
}
@Override
public ParameterMetadataBuilder getParameterMetadataBuilder() {
return new Neo4jParameterMetadataBuilder();
}
/**
* Returns the key of the entity targeted by the represented association, retrieved from the given
* tuple.
*
* @param tuple the tuple from which to retrieve the referenced entity key
* @return the key of the entity targeted by the represented association
*/
private EntityKey getEntityKey(
Tuple tuple, AssociatedEntityKeyMetadata associatedEntityKeyMetadata) {
Object[] columnValues =
new Object[associatedEntityKeyMetadata.getAssociationKeyColumns().length];
int i = 0;
for (String associationKeyColumn : associatedEntityKeyMetadata.getAssociationKeyColumns()) {
columnValues[i] = tuple.get(associationKeyColumn);
i++;
}
return new EntityKey(associatedEntityKeyMetadata.getEntityKeyMetadata(), columnValues);
}
@Override
public DuplicateInsertPreventionStrategy getDuplicateInsertPreventionStrategy(
EntityKeyMetadata entityKeyMetadata) {
// Only for non-composite keys (= one column) Neo4j supports unique key constraints; Hence an
// explicit look-up
// is required to detect duplicate insertions when using composite keys
return entityKeyMetadata.getColumnNames().length == 1
? DuplicateInsertPreventionStrategy.NATIVE
: DuplicateInsertPreventionStrategy.LOOK_UP;
}
}