feat(java,info): support multi-property in yaml

maven-projects/info/src/main/java/org/apache/graphar/info/EdgeInfo.java

@@ -32,6 +32,7 @@
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
 import org.apache.graphar.info.type.AdjListType;
+import org.apache.graphar.info.type.Cardinality;
 import org.apache.graphar.info.type.DataType;
 import org.apache.graphar.info.yaml.EdgeYaml;
 import org.apache.graphar.info.yaml.GraphYaml;
@@ -496,12 +497,14 @@ public URI getEdgesNumFileUri(AdjListType adjListType, long vertexChunkIndex) {
     }
 
     public void dump(Writer output) {
+        isValidated();
         Yaml yaml = new Yaml(GraphYaml.getRepresenter(), GraphYaml.getDumperOptions());
         EdgeYaml edgeYaml = new EdgeYaml(this);
         yaml.dump(edgeYaml, output);
     }
 
     public String dump() {
+        isValidated();
         Yaml yaml = new Yaml(GraphYaml.getRepresenter(), GraphYaml.getDumperOptions());
         EdgeYaml edgeYaml = new EdgeYaml(this);
         return yaml.dump(edgeYaml);
@@ -626,6 +629,10 @@ public boolean isValidated() {
             }
 
             for (Property p : pg.getPropertyList()) {
+                if (p.getCardinality() != Cardinality.SINGLE) {
+                    // edge property only supports single cardinality
+                    return false;
+                }
                 if (propertyNameSet.contains(p.getName())) {
                     return false;
                 }

maven-projects/info/src/main/java/org/apache/graphar/info/GraphInfo.java

@@ -128,18 +128,21 @@ private GraphInfo(
     }
 
     public void dump(URI storeUri, Writer output) {
+        isValidated();
         Yaml yaml = new Yaml(GraphYaml.getRepresenter(), GraphYaml.getDumperOptions());
         GraphYaml graphYaml = new GraphYaml(storeUri, this);
         yaml.dump(graphYaml, output);
     }
 
     public String dump(URI storeUri) {
+        isValidated();
         Yaml yaml = new Yaml(GraphYaml.getRepresenter(), GraphYaml.getDumperOptions());
         GraphYaml graphYaml = new GraphYaml(storeUri, this);
         return yaml.dump(graphYaml);
     }
 
     public String dump() {
+        isValidated();
         Yaml yaml = new Yaml(GraphYaml.getRepresenter(), GraphYaml.getDumperOptions());
         GraphYaml graphYaml = new GraphYaml(this);
         return yaml.dump(graphYaml);

maven-projects/info/src/main/java/org/apache/graphar/info/Property.java

@@ -19,27 +19,44 @@
 
 package org.apache.graphar.info;
 
+import org.apache.graphar.info.type.Cardinality;
 import org.apache.graphar.info.type.DataType;
 import org.apache.graphar.info.yaml.PropertyYaml;
 
 public class Property {
     private final String name;
     private final DataType dataType;
+    private final Cardinality cardinality;
     private final boolean primary;
     private final boolean nullable;
 
     public Property(String name, DataType dataType, boolean primary, boolean nullable) {
+        this(name, dataType, Cardinality.SINGLE, primary, nullable);
+    }
+
+    public Property(
+            String name,
+            DataType dataType,
+            Cardinality cardinality,
+            boolean primary,
+            boolean nullable) {
         this.name = name;
         this.dataType = dataType;
+        this.cardinality = cardinality;
         this.primary = primary;
         this.nullable = nullable;
     }
 
-    Property(PropertyYaml yamlParser) {
+    public Property(PropertyYaml yamlParser) {
         this.name = yamlParser.getName();
         this.dataType = DataType.fromString(yamlParser.getData_type());
         this.primary = yamlParser.getIs_primary();
         this.nullable = yamlParser.getIs_nullable();
+        Cardinality cardinality = Cardinality.SINGLE;
+        if (yamlParser.getCardinality() != null && !yamlParser.getCardinality().isEmpty()) {
+            cardinality = Cardinality.fromString(yamlParser.getCardinality());
+        }
+        this.cardinality = cardinality;
     }
 
     public String getName() {
@@ -57,4 +74,8 @@ public boolean isPrimary() {
     public boolean isNullable() {
         return nullable;
     }
+
+    public Cardinality getCardinality() {
+        return cardinality;
+    }
 }

maven-projects/info/src/main/java/org/apache/graphar/info/PropertyGroup.java

@@ -28,6 +28,7 @@
 import java.util.function.Function;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
+import org.apache.graphar.info.type.Cardinality;
 import org.apache.graphar.info.type.DataType;
 import org.apache.graphar.info.type.FileType;
 import org.apache.graphar.util.GeneralParams;
@@ -137,6 +138,9 @@ public boolean isValidated() {
             if (property.getDataType() == DataType.LIST && fileType == FileType.CSV) {
                 return false;
             }
+            if (property.getCardinality() != Cardinality.SINGLE && fileType == FileType.CSV) {
+                return false;
+            }
         }
 
         return true;
@@ -216,6 +220,11 @@ int getPropertyGroupNum() {
         return propertyGroupList.size();
     }
 
+    public Cardinality getCardinality(String propertyName) {
+        checkPropertyExist(propertyName);
+        return properties.get(propertyName).getCardinality();
+    }
+
     DataType getPropertyType(String propertyName) {
         checkPropertyExist(propertyName);
         return properties.get(propertyName).getDataType();

maven-projects/info/src/main/java/org/apache/graphar/info/VertexInfo.java

@@ -25,6 +25,7 @@
 import java.util.List;
 import java.util.Optional;
 import java.util.Set;
+import org.apache.graphar.info.type.Cardinality;
 import org.apache.graphar.info.type.DataType;
 import org.apache.graphar.info.yaml.GraphYaml;
 import org.apache.graphar.info.yaml.VertexYaml;
@@ -85,6 +86,10 @@ public int getPropertyGroupNum() {
         return propertyGroups.getPropertyGroupNum();
     }
 
+    public Cardinality getCardinality(String propertyName) {
+        return propertyGroups.getCardinality(propertyName);
+    }
+
     public DataType getPropertyType(String propertyName) {
         return propertyGroups.getPropertyType(propertyName);
     }
@@ -124,12 +129,14 @@ public URI getVerticesNumFileUri() {
     }
 
     public void dump(Writer output) {
+        isValidated();
         Yaml yaml = new Yaml(GraphYaml.getRepresenter(), GraphYaml.getDumperOptions());
         VertexYaml vertexYaml = new VertexYaml(this);
         yaml.dump(vertexYaml, output);
     }
 
     public String dump() {
+        isValidated();
         Yaml yaml = new Yaml(GraphYaml.getRepresenter(), GraphYaml.getDumperOptions());
         VertexYaml vertexYaml = new VertexYaml(this);
         return yaml.dump(vertexYaml);

maven-projects/info/src/main/java/org/apache/graphar/info/saver/BaseGraphInfoSaver.java

@@ -32,6 +32,11 @@ public abstract class BaseGraphInfoSaver implements GraphInfoSaver {
 
     @Override
     public void save(URI graphInfoUri, GraphInfo graphInfo) throws IOException {
+        // if graphInfoUri is a directory then save to ${graphInfo.name}.graph.yml
+        if (graphInfoUri.getPath().endsWith("/")) {
+            graphInfoUri =
+                    URI.create(graphInfoUri.toString() + graphInfo.getName() + ".graph.yaml");
+        }
         Writer writer = writeYaml(graphInfoUri);
         graphInfo.dump(graphInfoUri, writer);
         writer.close();
@@ -48,13 +53,22 @@ public void save(URI graphInfoUri, GraphInfo graphInfo) throws IOException {
 
     @Override
     public void save(URI vertexInfoUri, VertexInfo vertexInfo) throws IOException {
+        // if vertexInfoUri is a directory then save to ${vertexInfo.type}.vertex.yml
+        if (vertexInfoUri.getPath().endsWith("/")) {
+            vertexInfoUri =
+                    URI.create(vertexInfoUri.toString() + vertexInfo.getType() + ".vertex.yaml");
+        }
         Writer vertexWriter = writeYaml(vertexInfoUri);
         vertexInfo.dump(vertexWriter);
         vertexWriter.close();
     }
 
     @Override
     public void save(URI edgeInfoUri, EdgeInfo edgeInfo) throws IOException {
+        // if edgeInfoUri is a directory then save to ${edgeInfo.getConcat()}.edge.yml
+        if (edgeInfoUri.getPath().endsWith("/")) {
+            edgeInfoUri = URI.create(edgeInfoUri.toString() + edgeInfo.getConcat() + ".edge.yaml");
+        }
         Writer edgeWriter = writeYaml(edgeInfoUri);
         edgeInfo.dump(edgeWriter);
         edgeWriter.close();

maven-projects/info/src/main/java/org/apache/graphar/info/type/Cardinality.java

@@ -0,0 +1,59 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.apache.graphar.info.type;
+
+/** Defines how multiple values are handled for a given property key. */
+public enum Cardinality {
+    /** Single value property */
+    SINGLE,
+    /** List of values property */
+    LIST,
+    /** Set of values property (no duplicates) */
+    SET;
+
+    public String toString() {
+        switch (this) {
+            case SINGLE:
+                return "single";
+            case LIST:
+                return "list";
+            case SET:
+                return "set";
+            default:
+                throw new IllegalArgumentException("Unknown cardinality: " + this);
+        }
+    }
+
+    public static Cardinality fromString(String cardinality) {
+        if (cardinality == null) {
+            return null;
+        }
+        switch (cardinality) {
+            case "single":
+                return SINGLE;
+            case "list":
+                return LIST;
+            case "set":
+                return SET;
+            default:
+                throw new IllegalArgumentException("Unknown cardinality: " + cardinality);
+        }
+    }
+}

maven-projects/info/src/main/java/org/apache/graphar/info/yaml/PropertyYaml.java

@@ -21,34 +21,33 @@
 
 import java.util.Optional;
 import org.apache.graphar.info.Property;
-import org.apache.graphar.info.type.DataType;
+import org.apache.graphar.info.type.Cardinality;
 
 public class PropertyYaml {
     private String name;
     private String data_type;
     private boolean is_primary;
     private Optional<Boolean> is_nullable;
+    private String cardinality;
 
     public PropertyYaml() {
         this.name = "";
         this.data_type = "";
         this.is_primary = false;
         this.is_nullable = Optional.empty();
+        this.cardinality = "single"; // Default to single
     }
 
     public PropertyYaml(Property property) {
         this.name = property.getName();
         this.data_type = property.getDataType().toString();
         this.is_primary = property.isPrimary();
         this.is_nullable = Optional.of(property.isNullable());
+        this.cardinality = property.getCardinality().toString();
     }
 
     Property toProperty() {
-        return new Property(
-                name,
-                DataType.fromString(data_type),
-                is_primary,
-                is_nullable.orElseGet(() -> !is_primary));
+        return new Property(this);
     }
 
     public String getName() {
@@ -82,4 +81,15 @@ public boolean getIs_nullable() {
     public void setIs_nullable(boolean is_nullable) {
         this.is_nullable = Optional.of(is_nullable);
     }
+
+    public String getCardinality() {
+        if (cardinality == null) {
+            return null;
+        }
+        return Cardinality.SINGLE.toString().equals(cardinality) ? null : cardinality;
+    }
+
+    public void setCardinality(String cardinality) {
+        this.cardinality = cardinality;
+    }
 }

maven-projects/info/src/main/java/org/apache/graphar/info/yaml/VertexYaml.java

@@ -30,13 +30,15 @@ public class VertexYaml {
     private String type;
     private long chunk_size;
     private List<PropertyGroupYaml> property_groups;
+    private List<String> labels;
     private String prefix;
     private String version;
 
     public VertexYaml() {
         this.type = "";
         this.chunk_size = 0;
         this.property_groups = new ArrayList<>();
+        this.labels = null;
         this.prefix = "";
         this.version = "";
     }
@@ -80,6 +82,17 @@ public void setProperty_groups(List<PropertyGroupYaml> property_groups) {
         this.property_groups = property_groups;
     }
 
+    public List<String> getLabels() {
+        if (labels == null) {
+            return null;
+        }
+        return labels.isEmpty() ? null : labels;
+    }
+
+    public void setLabels(List<String> labels) {
+        this.labels = labels;
+    }
+
     public String getPrefix() {
         return prefix;
     }