[DE-1070] Configurable label field name (#19)

* configurable label field name

* updated documentation

* fixed spotbugs checks

Author: rashtao

README.md

@@ -283,6 +283,7 @@ Graph configuration properties are prefixed with `gremlin.arangodb.conf.graph`:
 | `gremlin.arangodb.conf.graph.name`                 | ArangoDB graph name                   | `tinkerpop` |
 | `gremlin.arangodb.conf.graph.enableDataDefinition` | Flag to allow data definition changes | `false`     |
 | `gremlin.arangodb.conf.graph.type`                 | Graph type: `SIMPLE` or `COMPLEX`     | `SIMPLE`    |
+| `gremlin.arangodb.conf.graph.labelField`           | Label field name                      | `_label`    |
 | `gremlin.arangodb.conf.graph.orphanCollections`    | List of orphan collections names      | -           |
 | `gremlin.arangodb.conf.graph.edgeDefinitions`      | List of edge definitions              | -           |
 
@@ -395,6 +396,11 @@ The ArangoDB TinkerPop Provider supports two graph types, which can be configure
 From an application perspective, this is the most flexible graph type that is backed by an ArangoDB graph composed of
 only 1 vertex collection and 1 edge definition.
 
+The `label` of each element is stored in a database document field. The label field name is configurable by setting the 
+configuration property `graph.labelField`, `_label` by default.
+
+The `SIMPLE` graph type is the default graph type.
+
 It has the following advantages:
 
 - It closely matches the Tinkerpop property graph
@@ -407,7 +413,7 @@ It has the following disadvantages:
 - All vertex types will be stored in the same vertex collection
 - All edge types will be stored in the same edge collection
 - It could not leverage the full potential of ArangoDB graph traversal
-- It could require an index on the `_label` field to improve performance
+- It could require an index on the label field to improve performance
 
 Example configuration:
 
@@ -443,7 +449,11 @@ to `v/foo`).
 ### COMPLEX Graph Type
 
 The `COMPLEX` graph type is backed by an ArangoDB graph composed potentially of multiple vertex collections and multiple
-edge definitions. It has the following advantages:
+edge definitions. 
+
+The `label` of each element is used as name for the related database collection.
+
+It has the following advantages:
 
 - It closely matches the ArangoDB graph structure
 - It allows multiple vertex collections and multiple edge collections
@@ -502,10 +512,12 @@ collection, by default named `vertex`. In a `COMPLEX` graph, vertices are stored
 Each vertex document contains:
 
 - Standard ArangoDB fields (`_id`, `_key`, `_rev`)
-- The field `_label`
 - Vertex properties as document fields
 - Meta-properties nested in the nested map `_meta`
 
+Additionally, in a `SIMPLE` graph:
+- The label field (`_label` by default)
+
 For example, the following Java code:
 
 [//]: <> (@formatter:off)
@@ -542,9 +554,11 @@ default named `edge`. In a `COMPLEX` graph, edges are stored in collections name
 Each edge document contains:
 
 - Standard ArangoDB edge fields (`_id`, `_key`, `_rev`, `_from`, `_to`)
-- The field `_label`
 - Edge properties as document fields
 
+Additionally, in a `SIMPLE` graph:
+- The label field (`_label` by default)
+
 For example, the following Java code:
 
 [//]: <> (@formatter:off)

spotbugs/spotbugs-exclude.xml

@@ -30,4 +30,9 @@
         <Bug pattern="SING_SINGLETON_HAS_NONPRIVATE_CONSTRUCTOR"/>
     </Match>
 
+    <Match>
+        <Class name="com.arangodb.tinkerpop.gremlin.persistence.serde.SerdeModule"/>
+        <Bug pattern="SE_BAD_FIELD"/>
+    </Match>
+
 </FindBugsFilter>

src/main/java/com/arangodb/tinkerpop/gremlin/client/ArangoDBGraphClient.java

@@ -54,7 +54,7 @@ public ArangoDBGraphClient(ArangoDBGraphConfig config, ElementIdFactory idFactor
                 .orElse(ArangoDefaults.DEFAULT_PROTOCOL);
         ObjectMapper mapper = JacksonMapperProvider
                 .of(ContentTypeFactory.of(protocol))
-                .registerModule(new SerdeModule(idFactory, config.graphType));
+                .registerModule(new SerdeModule(idFactory, config));
         aqlDeserializer = new AqlDeserializer(graph, mapper);
         db = new ArangoDB.Builder()
                 .loadProperties(config.driverConfig)
@@ -305,7 +305,7 @@ public void updateVertex(ArangoDBVertex vertex) {
 
     public Iterator<VertexData> getVertexNeighbors(ElementId vertexId, Set<String> edgeCollections, Direction direction, String[] labels) {
         logger.debug("Get vertex {}:{} Neighbors, in {}, from collections {}", vertexId, direction, config.graphName, edgeCollections);
-        String query = ArangoDBQueryBuilder.readVertexNeighbors(config.graphName, direction, config.graphType, labels);
+        String query = ArangoDBQueryBuilder.readVertexNeighbors(config.graphName, direction, config, labels);
         Map<String, Object> params = new HashMap<>();
         params.put("vertexId", vertexId);
         params.put("edgeCollections", edgeCollections);
@@ -317,7 +317,7 @@ public Iterator<VertexData> getVertexNeighbors(ElementId vertexId, Set<String> e
 
     public Iterator<EdgeData> getVertexEdges(ElementId vertexId, Set<String> edgeCollections, Direction direction, String[] labels) {
         logger.debug("Get vertex {}:{} Edges, in {}, from collections {}", vertexId, direction, config.graphName, edgeCollections);
-        String query = ArangoDBQueryBuilder.readVertexEdges(config.graphName, direction, config.graphType, labels);
+        String query = ArangoDBQueryBuilder.readVertexEdges(config.graphName, direction, config, labels);
         Map<String, Object> params = new HashMap<>();
         params.put("vertexId", vertexId);
         params.put("edgeCollections", edgeCollections);

src/main/java/com/arangodb/tinkerpop/gremlin/client/ArangoDBQueryBuilder.java

@@ -22,36 +22,34 @@
 import com.arangodb.tinkerpop.gremlin.structure.ArangoDBGraphConfig;
 import org.apache.tinkerpop.gremlin.structure.Direction;
 
-import static com.arangodb.tinkerpop.gremlin.utils.Fields.LABEL;
-
 
 public class ArangoDBQueryBuilder {
 
     private ArangoDBQueryBuilder() {
     }
 
-    public static String readVertexNeighbors(String graphName, Direction direction, ArangoDBGraphConfig.GraphType type, String[] labels) {
-        return oneStepTraversal(graphName, direction, type, labels)
+    public static String readVertexNeighbors(String graphName, Direction direction, ArangoDBGraphConfig config, String[] labels) {
+        return oneStepTraversal(graphName, direction, config, labels)
                 .append(" RETURN v")
                 .toString();
     }
 
-    public static String readVertexEdges(String graphName, Direction direction, ArangoDBGraphConfig.GraphType type, String[] labels) {
-        return oneStepTraversal(graphName, direction, type, labels)
+    public static String readVertexEdges(String graphName, Direction direction, ArangoDBGraphConfig config, String[] labels) {
+        return oneStepTraversal(graphName, direction, config, labels)
                 .append(" RETURN e")
                 .toString();
     }
 
-    private static StringBuilder oneStepTraversal(String graphName, Direction direction, ArangoDBGraphConfig.GraphType type, String[] labels) {
+    private static StringBuilder oneStepTraversal(String graphName, Direction direction, ArangoDBGraphConfig config, String[] labels) {
         StringBuilder query = new StringBuilder()
                 .append("FOR v, e IN 1..1 ")
                 .append(toArangoDirection(direction))
                 .append(" @vertexId GRAPH ")
                 .append(escape(graphName))
                 .append(" OPTIONS {edgeCollections: @edgeCollections}");
         if (labels.length > 0) {
-            if (type == ArangoDBGraphConfig.GraphType.SIMPLE) {
-                query.append(" FILTER e." + LABEL + " IN @labels");
+            if (config.graphType == ArangoDBGraphConfig.GraphType.SIMPLE) {
+                query.append(" FILTER e." + config.labelField + " IN @labels");
             } else {
                 query.append(" FILTER PARSE_COLLECTION(e) IN @edgeCollections");
             }

src/main/java/com/arangodb/tinkerpop/gremlin/persistence/serde/EdgeDataDeserializer.java

@@ -19,7 +19,6 @@
 import com.arangodb.tinkerpop.gremlin.persistence.EdgeData;
 import com.arangodb.tinkerpop.gremlin.persistence.ElementId;
 import com.arangodb.tinkerpop.gremlin.structure.ArangoDBGraphConfig;
-import com.arangodb.tinkerpop.gremlin.utils.Fields;
 import com.fasterxml.jackson.core.JsonParser;
 import com.fasterxml.jackson.core.ObjectCodec;
 import com.fasterxml.jackson.databind.DeserializationContext;
@@ -34,10 +33,10 @@
 
 public class EdgeDataDeserializer extends JsonDeserializer<EdgeData> {
 
-    private final ArangoDBGraphConfig.GraphType type;
+    private final ArangoDBGraphConfig config;
 
-    public EdgeDataDeserializer(ArangoDBGraphConfig.GraphType type) {
-        this.type = type;
+    public EdgeDataDeserializer(ArangoDBGraphConfig config) {
+        this.config = config;
     }
 
     @Override
@@ -46,8 +45,8 @@ public EdgeData deserialize(JsonParser p, DeserializationContext ctx) throws IOE
         ObjectNode root = c.readTree(p);
         ElementId id = c.treeToValue(root.get(ID), ElementId.class);
         String label;
-        if (type == ArangoDBGraphConfig.GraphType.SIMPLE) {
-            label = root.get(LABEL).asText();
+        if (config.graphType == ArangoDBGraphConfig.GraphType.SIMPLE) {
+            label = root.get(config.labelField).asText();
         } else {
             label = id.getLabel();
         }
@@ -56,7 +55,7 @@ public EdgeData deserialize(JsonParser p, DeserializationContext ctx) throws IOE
         EdgeData data = new EdgeData(label, id, from, to);
 
         for (Map.Entry<String, JsonNode> prop : root.properties()) {
-            if (!Fields.isReserved(prop.getKey())) {
+            if (!config.isReservedField(prop.getKey())) {
                 data.put(prop.getKey(), c.treeToValue(prop.getValue(), Object.class));
             }
         }

src/main/java/com/arangodb/tinkerpop/gremlin/persistence/serde/EdgeDataSerializer.java

@@ -30,10 +30,10 @@
 
 public class EdgeDataSerializer extends JsonSerializer<EdgeData> {
 
-    private final ArangoDBGraphConfig.GraphType type;
+    private final ArangoDBGraphConfig config;
 
-    public EdgeDataSerializer(ArangoDBGraphConfig.GraphType type) {
-        this.type = type;
+    public EdgeDataSerializer(ArangoDBGraphConfig config) {
+        this.config = config;
     }
 
     @Override
@@ -42,8 +42,8 @@ public void serialize(EdgeData data, JsonGenerator gen, SerializerProvider seria
         if (data.getKey() != null) {
             gen.writeStringField(Fields.KEY, data.getKey());
         }
-        if (type == ArangoDBGraphConfig.GraphType.SIMPLE) {
-            gen.writeStringField(LABEL, data.getLabel());
+        if (config.graphType == ArangoDBGraphConfig.GraphType.SIMPLE) {
+            gen.writeStringField(config.labelField, data.getLabel());
         }
         gen.writeObjectField(FROM, data.getFrom());
         gen.writeObjectField(TO, data.getTo());

src/main/java/com/arangodb/tinkerpop/gremlin/persistence/serde/SerdeModule.java

@@ -24,27 +24,27 @@
 
 public class SerdeModule extends SimpleModule {
     private final ElementIdFactory idFactory;
-    private final ArangoDBGraphConfig.GraphType graphType;
+    private final ArangoDBGraphConfig config;
 
-    public SerdeModule(ElementIdFactory idFactory, ArangoDBGraphConfig.GraphType graphType) {
+    public SerdeModule(ElementIdFactory idFactory, ArangoDBGraphConfig config) {
         this.idFactory = idFactory;
-        this.graphType = graphType;
+        this.config = config;
     }
 
     @Override
     public void setupModule(SetupContext context) {
         SimpleSerializers serializers = new SimpleSerializers();
         serializers.addSerializer(ElementId.class, new ElementIdSerializer());
-        serializers.addSerializer(VertexData.class, new VertexDataSerializer(graphType));
-        serializers.addSerializer(EdgeData.class, new EdgeDataSerializer(graphType));
+        serializers.addSerializer(VertexData.class, new VertexDataSerializer(config));
+        serializers.addSerializer(EdgeData.class, new EdgeDataSerializer(config));
         serializers.addSerializer(VariablesData.class, new VariablesDataSerializer());
         context.addSerializers(serializers);
 
         SimpleDeserializers deserializers = new SimpleDeserializers();
         deserializers.addDeserializer(ElementId.class, new ElementIdDeserializer(idFactory));
-        deserializers.addDeserializer(VertexData.class, new VertexDataDeserializer(graphType));
-        deserializers.addDeserializer(EdgeData.class, new EdgeDataDeserializer(graphType));
-        deserializers.addDeserializer(VariablesData.class, new VariablesDataDeserializer());
+        deserializers.addDeserializer(VertexData.class, new VertexDataDeserializer(config));
+        deserializers.addDeserializer(EdgeData.class, new EdgeDataDeserializer(config));
+        deserializers.addDeserializer(VariablesData.class, new VariablesDataDeserializer(config));
         context.addDeserializers(deserializers);
     }
 }

src/main/java/com/arangodb/tinkerpop/gremlin/persistence/serde/VariablesDataDeserializer.java

@@ -17,7 +17,7 @@
 package com.arangodb.tinkerpop.gremlin.persistence.serde;
 
 import com.arangodb.tinkerpop.gremlin.persistence.VariablesData;
-import com.arangodb.tinkerpop.gremlin.utils.Fields;
+import com.arangodb.tinkerpop.gremlin.structure.ArangoDBGraphConfig;
 import com.fasterxml.jackson.core.JsonParser;
 import com.fasterxml.jackson.core.ObjectCodec;
 import com.fasterxml.jackson.databind.DeserializationContext;
@@ -31,6 +31,12 @@
 import static com.arangodb.tinkerpop.gremlin.utils.Fields.*;
 
 public class VariablesDataDeserializer extends JsonDeserializer<VariablesData> {
+    private final ArangoDBGraphConfig config;
+
+    public VariablesDataDeserializer(ArangoDBGraphConfig config) {
+        this.config = config;
+    }
+
     @Override
     public VariablesData deserialize(JsonParser p, DeserializationContext ctx) throws IOException {
         ObjectCodec c = p.getCodec();
@@ -40,7 +46,7 @@ public VariablesData deserialize(JsonParser p, DeserializationContext ctx) throw
         VariablesData data = new VariablesData(key, version);
 
         for (Map.Entry<String, JsonNode> prop : root.properties()) {
-            if (!Fields.isReserved(prop.getKey())) {
+            if (!config.isReservedField(prop.getKey())) {
                 data.put(prop.getKey(), c.treeToValue(prop.getValue(), Object.class));
             }
         }

src/main/java/com/arangodb/tinkerpop/gremlin/persistence/serde/VertexDataDeserializer.java

@@ -20,7 +20,6 @@
 import com.arangodb.tinkerpop.gremlin.persistence.VertexData;
 import com.arangodb.tinkerpop.gremlin.persistence.VertexPropertyData;
 import com.arangodb.tinkerpop.gremlin.structure.ArangoDBGraphConfig;
-import com.arangodb.tinkerpop.gremlin.utils.Fields;
 import com.fasterxml.jackson.core.JsonParser;
 import com.fasterxml.jackson.core.ObjectCodec;
 import com.fasterxml.jackson.databind.DeserializationContext;
@@ -36,10 +35,10 @@
 
 class VertexDataDeserializer extends JsonDeserializer<VertexData> {
 
-    private final ArangoDBGraphConfig.GraphType type;
+    private final ArangoDBGraphConfig config;
 
-    VertexDataDeserializer(ArangoDBGraphConfig.GraphType type) {
-        this.type = type;
+    VertexDataDeserializer(ArangoDBGraphConfig config) {
+        this.config = config;
     }
 
     @Override
@@ -48,8 +47,8 @@ public VertexData deserialize(JsonParser p, DeserializationContext ctx) throws I
         ObjectNode root = c.readTree(p);
         ElementId id = c.treeToValue(root.get(ID), ElementId.class);
         String label;
-        if (type == ArangoDBGraphConfig.GraphType.SIMPLE) {
-            label = root.get(LABEL).asText();
+        if (config.graphType == ArangoDBGraphConfig.GraphType.SIMPLE) {
+            label = root.get(config.labelField).asText();
         } else {
             label = id.getLabel();
         }
@@ -60,7 +59,7 @@ public VertexData deserialize(JsonParser p, DeserializationContext ctx) throws I
                 : Collections.emptyMap();
 
         for (Map.Entry<String, JsonNode> prop : root.properties()) {
-            if (!Fields.isReserved(prop.getKey())) {
+            if (!config.isReservedField(prop.getKey())) {
                 VertexPropertyData pd = new VertexPropertyData(c.treeToValue(prop.getValue(), Object.class));
                 String key = prop.getKey();
                 pd.putAll(meta.get(key));

src/main/java/com/arangodb/tinkerpop/gremlin/persistence/serde/VertexDataSerializer.java

@@ -28,14 +28,12 @@
 import java.util.HashMap;
 import java.util.Map;
 
-import static com.arangodb.tinkerpop.gremlin.utils.Fields.LABEL;
-
 class VertexDataSerializer extends JsonSerializer<VertexData> {
 
-    private final ArangoDBGraphConfig.GraphType type;
+    private final ArangoDBGraphConfig config;
 
-    VertexDataSerializer(ArangoDBGraphConfig.GraphType type) {
-        this.type = type;
+    VertexDataSerializer(ArangoDBGraphConfig config) {
+        this.config = config;
     }
 
     @Override
@@ -44,8 +42,8 @@ public void serialize(VertexData data, JsonGenerator gen, SerializerProvider ser
         if (data.getKey() != null) {
             gen.writeStringField(Fields.KEY, data.getKey());
         }
-        if (type == ArangoDBGraphConfig.GraphType.SIMPLE) {
-            gen.writeStringField(LABEL, data.getLabel());
+        if (config.graphType == ArangoDBGraphConfig.GraphType.SIMPLE) {
+            gen.writeStringField(config.labelField, data.getLabel());
         }
 
         Map<String, Map<String, Object>> meta = new HashMap<>();