[Spark] Update the Spark library to align with the latest file format…

… design (#144)

README.rst

@@ -80,7 +80,7 @@ Each type of vertices (with the same label) constructs a logical vertex table, w
 Given a vertex id and the vertex label, a vertex is uniquely identifiable and its respective properties can be accessed from this table. The vertex id is further used to identify the source and destination vertices when maintaining the topology of the graph.
 
 .. image:: https://alibaba.github.io/GraphAr/_images/vertex_logical_table.png
-  :width: 700
+  :width: 650
   :align: center
   :alt: vertex logical table
 
@@ -92,7 +92,7 @@ The logical vertex table will be partitioned into multiple continuous vertex chu
 Take the "person" vertex table as an example, if the chunk size is set to be 500, the logical table will be separated into sub-logical-tables of 500 rows with the exception of the last one, which may have less than 500 rows. The columns for maintaining properties will also be divided into distinct groups (e.g., 2 for our example). As a result, a total of 4 physical vertex tables are created for storing the example logical table, which can be seen from the following figure.
 
 .. image:: https://alibaba.github.io/GraphAr/_images/vertex_physical_table.png
-  :width: 700
+  :width: 650
   :align: center
   :alt: vertex physical table
 
@@ -107,7 +107,7 @@ For maintaining a type of edges (that with the same triplet of the source label,
 Take the logical table for "person likes person" edges as an example, the logical edge table looks like:
 
 .. image:: https://alibaba.github.io/GraphAr/_images/edge_logical_table.png
-  :width: 700
+  :width: 650
   :align: center
   :alt: edge logical table
 
@@ -127,12 +127,12 @@ Additionally, the partition of the offset table should be in alignment with the
 Take the "person knows person" edges to illustrate. Suppose the vertex chunk size is set to 500 and the edge chunk size is 1024, the edges will be saved in the following physical tables:
 
 .. image:: https://alibaba.github.io/GraphAr/_images/edge_physical_table1.png
-  :width: 700
+  :width: 650
   :align: center
   :alt: edge logical table1
 
 .. image:: https://alibaba.github.io/GraphAr/_images/edge_physical_table2.png
-  :width: 700
+  :width: 650
   :align: center
   :alt: edge logical table2
 

docs/user-guide/file-format.rst

@@ -23,6 +23,8 @@ And each edge contains:
 The following is an example property graph containing two types of vertices ("person" and "comment") and three types of edges.
 
 .. image:: ../images/property_graph.png
+   :width: 700
+   :align: center
    :alt: property graph
 
 
@@ -36,6 +38,8 @@ Each type of vertices (with the same label) constructs a logical vertex table, w
 Given a vertex id and the vertex label, a vertex is uniquely identifiable and its respective properties can be accessed from this table. The vertex id is further used to identify the source and destination vertices when maintaining the topology of the graph.
 
 .. image:: ../images/vertex_logical_table.png
+   :width: 650
+   :align: center
    :alt: vertex logical table
 
 .. note::
@@ -50,6 +54,8 @@ The logical vertex table will be partitioned into multiple continuous vertex chu
 Take the "person" vertex table as an example, if the chunk size is set to be 500, the logical table will be separated into sub-logical-tables of 500 rows with the exception of the last one, which may have less than 500 rows. The columns for maintaining properties will also be divided into distinct groups (e.g., 2 for our example). As a result, a total of 4 physical vertex tables are created for storing the example logical table, which can be seen from the following figure.
 
 .. image:: ../images/vertex_physical_table.png
+   :width: 650
+   :align: center
    :alt: vertex physical table
 
 
@@ -63,6 +69,8 @@ For maintaining a type of edges (that with the same triplet of the source label,
 Take the logical table for "person likes person" edges as an example, the logical edge table looks like:
 
 .. image:: ../images/edge_logical_table.png
+   :width: 650
+   :align: center
    :alt: edge logical table
 
 Physical table of edges
@@ -80,8 +88,13 @@ Additionally, the partition of the offset table should be in alignment with the
 Take the "person knows person" edges to illustrate. Suppose the vertex chunk size is set to 500 and the edge chunk size is 1024, the edges will be saved in the following physical tables:
 
 .. image:: ../images/edge_physical_table1.png
+   :width: 650
+   :align: center
    :alt: edge physical table1
+
 .. image:: ../images/edge_physical_table2.png
+   :width: 650
+   :align: center
    :alt: edge physical table2
 
 .. tip::

spark/src/main/scala/com/alibaba/graphar/EdgeInfo.scala

@@ -44,8 +44,9 @@ class EdgeInfo() {
     val tot: Int = adj_lists.size
     for ( k <- 0 to tot - 1 ) {
       val adj_list = adj_lists.get(k)
-      if (adj_list.getAdjList_type_in_gar == adj_list_type)
+      if (adj_list.getAdjList_type_in_gar == adj_list_type) {
         return true
+      }
     }
     return false
   }
@@ -260,10 +261,12 @@ class EdgeInfo() {
 
   /** Check if the edge info is validated. */
   def isValidated(): Boolean = {
-    if (src_label == "" || edge_label == "" || dst_label == "")
+    if (src_label == "" || edge_label == "" || dst_label == "") {
       return false
-    if (chunk_size <= 0 || src_chunk_size <= 0 || dst_chunk_size <= 0)
+    }
+    if (chunk_size <= 0 || src_chunk_size <= 0 || dst_chunk_size <= 0) {
       return false
+    }
     val tot: Int = adj_lists.size
     for ( k <- 0 to tot - 1 ) {
       val adj_list = adj_lists.get(k)
@@ -274,25 +277,71 @@ class EdgeInfo() {
         val pg: PropertyGroup = property_groups.get(i)
         val properties = pg.getProperties
         val num = properties.size
-        if (num == 0)
+        if (num == 0) {
           return false
+        }
         val pg_file_type = pg.getFile_type_in_gar
       }
     }
     return true
   }
 
+  /** Get the vertex num file path
+   *
+   *  @param adj_list_type type of adj list structure.
+   *  @return the vertex num file path. If edge info not support the adj list type,
+   *          raise an IllegalArgumentException error.
+   */
+  def getVerticesNumFilePath(adj_list_type: AdjListType.Value): String = {
+    if (containAdjList(adj_list_type) == false) {
+      throw new IllegalArgumentException
+    }
+    val str: String = prefix + getAdjListPrefix(adj_list_type) + "vertex_count"
+    return str
+  }
+
+  /** Get the path prefix of the edge num file path
+   *
+   *  @param adj_list_type type of adj list structure.
+   *  @return the edge num file path. If edge info not support the adj list type,
+   *          raise an IllegalArgumentException error.
+   */
+  def getEdgesNumPathPrefix(adj_list_type: AdjListType.Value): String = {
+    if (containAdjList(adj_list_type) == false) {
+      throw new IllegalArgumentException
+    }
+    val str: String = prefix + getAdjListPrefix(adj_list_type) + "edge_count"
+    return str
+  }
+
+  /** Get the edge num file path of the vertex chunk
+   *
+   *  @param chunk_index index of vertex chunk.
+   *  @param adj_list_type type of adj list structure.
+   *  @return the edge num file path. If edge info not support the adj list type,
+   *          raise an IllegalArgumentException error.
+   */
+  def getEdgesNumFilePath(chunk_index: Long, adj_list_type: AdjListType.Value): String = {
+    if (containAdjList(adj_list_type) == false) {
+      throw new IllegalArgumentException
+    }
+    val str: String = prefix + getAdjListPrefix(adj_list_type) + "edge_count" +
+           chunk_index.toString()
+    return str
+  }
+
   /** Get the adj list offset chunk file path of vertex chunk
    *  the offset chunks is aligned with the vertex chunks
    *
-   *  @param chunk_inde index of vertex chunk.
+   *  @param chunk_index index of vertex chunk.
    *  @param adj_list_type type of adj list structure.
    *  @return the offset chunk file path. If edge info not support the adj list type,
    *          raise an IllegalArgumentException error.
    */
   def getAdjListOffsetFilePath(chunk_index: Long, adj_list_type: AdjListType.Value) : String = {
-    if (containAdjList(adj_list_type) == false)
+    if (containAdjList(adj_list_type) == false) {
       throw new IllegalArgumentException
+    }
     val str: String = prefix + getAdjListPrefix(adj_list_type) + "offset/chunk" +
            chunk_index.toString()
     return str
@@ -305,8 +354,9 @@ class EdgeInfo() {
    *          raise an IllegalArgumentException error.
    */
   def getOffsetPathPrefix(adj_list_type: AdjListType.Value) : String = {
-    if (containAdjList(adj_list_type) == false)
+    if (containAdjList(adj_list_type) == false) {
       throw new IllegalArgumentException
+    }
     return prefix + getAdjListPrefix(adj_list_type) + "offset/"
   }
 

spark/src/main/scala/com/alibaba/graphar/VertexInfo.scala

@@ -151,15 +151,17 @@ class VertexInfo() {
    * @return true if the vertex info is validated, otherwise return false.
    */
  def isValidated(): Boolean = {
-    if (label == "" || chunk_size <= 0)
+    if (label == "" || chunk_size <= 0) {
       return false
+    }
     val len: Int = property_groups.size
     for ( i <- 0 to len - 1 ) {
       val pg: PropertyGroup = property_groups.get(i)
       val properties = pg.getProperties
       val num = properties.size
-      if (num == 0)
+      if (num == 0) {
         return false
+      }
       val file_type = pg.getFile_type_in_gar
     }
     return true
@@ -177,15 +179,17 @@ class VertexInfo() {
    * @return chunk file path.
    */
   def getFilePath(property_group: PropertyGroup, chunk_index: Long): String = {
-    if (containPropertyGroup(property_group) == false)
+    if (containPropertyGroup(property_group) == false) {
       throw new IllegalArgumentException
+    }
     var str: String = ""
     if (property_group.getPrefix == "") {
       val properties = property_group.getProperties
       val num = properties.size
       for ( j <- 0 to num - 1 ) {
-        if (j > 0)
+        if (j > 0) {
           str += GeneralParams.regularSeperator
+        }
         str += properties.get(j).getName;
       }
       str += "/"
@@ -201,8 +205,9 @@ class VertexInfo() {
    * @return the path prefix of the property group chunk files.
    */
   def getPathPrefix(property_group: PropertyGroup): String = {
-    if (containPropertyGroup(property_group) == false)
+    if (containPropertyGroup(property_group) == false) {
       throw new IllegalArgumentException
+    }
     var str: String = ""
     if (property_group.getPrefix == "") {
       val properties = property_group.getProperties

spark/src/main/scala/com/alibaba/graphar/reader/EdgeReader.scala

@@ -18,6 +18,7 @@ package com.alibaba.graphar.reader
 import com.alibaba.graphar.utils.{IndexGenerator, DataFrameConcat}
 import com.alibaba.graphar.{GeneralParams, EdgeInfo, FileType, AdjListType, PropertyGroup}
 import com.alibaba.graphar.datasources._
+import com.alibaba.graphar.utils.FileSystem
 
 import org.apache.spark.sql.{DataFrame, SparkSession}
 import org.apache.spark.sql.types._
@@ -38,15 +39,55 @@ class EdgeReader(prefix: String,  edgeInfo: EdgeInfo, adjListType: AdjListType.V
     throw new IllegalArgumentException
   }
 
+  /** Load the total number of src/dst vertices for this edge type. */
+  def readVerticesNumber(): Long = {
+    val file_path = prefix + "/" + edgeInfo.getVerticesNumFilePath(adjListType)
+    val number = FileSystem.readValue(file_path, spark.sparkContext.hadoopConfiguration)
+    return number
+  }
+
+  /** Load the chunk number of src/dst vertices. */
+  def readVertexChunkNumber(): Long = {
+    val vertices_number = readVerticesNumber
+    var vertex_chunk_size = edgeInfo.getSrc_chunk_size
+    if (adjListType == AdjListType.ordered_by_dest || adjListType == AdjListType.unordered_by_dest) {
+      vertex_chunk_size = edgeInfo.getDst_chunk_size
+    }
+    val vertex_chunk_number = (vertices_number + vertex_chunk_size - 1) / vertex_chunk_size
+    return vertex_chunk_number
+  }
+
+  /** Load the number of edges for the vertex chunk.
+   *
+   * @param chunk_index index of vertex chunk
+   * @return the number of edges
+   */
+  def readEdgesNumber(chunk_index: Long): Long = {
+    val file_path = prefix + "/" + edgeInfo.getEdgesNumFilePath(chunk_index, adjListType)
+    val number = FileSystem.readValue(file_path, spark.sparkContext.hadoopConfiguration)
+    return number
+  }
+
+  /** Load the total number of edges for this edge type. */
+  def readEdgesNumber(): Long = {
+    val vertex_chunk_number = readVertexChunkNumber
+    var number: Long  = 0
+    for (i <- 0L until vertex_chunk_number) {
+      number += readEdgesNumber(i)
+    }
+    return number
+  }
+
   /** Load a single offset chunk as a DataFrame.
    *
    * @param chunk_index index of offset chunk
    * @return offset chunk DataFrame. Raise IllegalArgumentException if adjListType is not
    *         AdjListType.ordered_by_source or AdjListType.ordered_by_dest.
    */
   def readOffset(chunk_index: Long): DataFrame = {
-    if (adjListType != AdjListType.ordered_by_source && adjListType != AdjListType.ordered_by_dest)
+    if (adjListType != AdjListType.ordered_by_source && adjListType != AdjListType.ordered_by_dest) {
       throw new IllegalArgumentException
+    }
     val file_type_in_gar = edgeInfo.getAdjListFileType(adjListType)
     val file_type = FileType.FileTypeToString(file_type_in_gar)
     val file_path = prefix + edgeInfo.getAdjListOffsetFilePath(chunk_index, adjListType)
@@ -112,8 +153,9 @@ class EdgeReader(prefix: String,  edgeInfo: EdgeInfo, adjListType: AdjListType.V
    *         raise an IllegalArgumentException error.
    */
   def readEdgePropertyChunk(propertyGroup: PropertyGroup, vertex_chunk_index: Long, chunk_index: Long): DataFrame = {
-    if (edgeInfo.containPropertyGroup(propertyGroup, adjListType) == false)
+    if (edgeInfo.containPropertyGroup(propertyGroup, adjListType) == false) {
       throw new IllegalArgumentException
+    }
     val file_type = propertyGroup.getFile_type()
     val file_path = prefix + edgeInfo.getPropertyFilePath(propertyGroup, adjListType, vertex_chunk_index, chunk_index)
     val df = spark.read.option("fileFormat", file_type).option("header", "true").format("com.alibaba.graphar.datasources.GarDataSource").load(file_path)
@@ -129,8 +171,9 @@ class EdgeReader(prefix: String,  edgeInfo: EdgeInfo, adjListType: AdjListType.V
    *         If edge info does not contain the property group, raise an IllegalArgumentException error.
    */
   def readEdgePropertyGroupForVertexChunk(propertyGroup: PropertyGroup, vertex_chunk_index: Long, addIndex: Boolean = true): DataFrame = {
-    if (edgeInfo.containPropertyGroup(propertyGroup, adjListType) == false)
+    if (edgeInfo.containPropertyGroup(propertyGroup, adjListType) == false) {
       throw new IllegalArgumentException
+    }
     val file_type = propertyGroup.getFile_type()
     val file_path = prefix + edgeInfo.getPropertyGroupPathPrefix(propertyGroup, adjListType, vertex_chunk_index)
     val df = spark.read.option("fileFormat", file_type).option("header", "true").format("com.alibaba.graphar.datasources.GarDataSource").load(file_path)
@@ -149,8 +192,9 @@ class EdgeReader(prefix: String,  edgeInfo: EdgeInfo, adjListType: AdjListType.V
    *         If edge info does not contain the property group, raise an IllegalArgumentException error.
    */
   def readEdgePropertyGroup(propertyGroup: PropertyGroup, addIndex: Boolean = true): DataFrame = {
-    if (edgeInfo.containPropertyGroup(propertyGroup, adjListType) == false)
+    if (edgeInfo.containPropertyGroup(propertyGroup, adjListType) == false) {
       throw new IllegalArgumentException
+    }
     val file_type = propertyGroup.getFile_type()
     val file_path = prefix + edgeInfo.getPropertyGroupPathPrefix(propertyGroup, adjListType)
     val df = spark.read.option("fileFormat", file_type).option("header", "true").option("recursiveFileLookup", "true").format("com.alibaba.graphar.datasources.GarDataSource").load(file_path)
@@ -170,13 +214,15 @@ class EdgeReader(prefix: String,  edgeInfo: EdgeInfo, adjListType: AdjListType.V
    */
   def readMultipleEdgePropertyGroupsForVertexChunk(propertyGroups: java.util.ArrayList[PropertyGroup], vertex_chunk_index: Long, addIndex: Boolean = true): DataFrame = {
     val len: Int = propertyGroups.size
-    if (len == 0)
+    if (len == 0) {
       return spark.emptyDataFrame
+    }
 
     val pg0: PropertyGroup = propertyGroups.get(0)
     val df0 = readEdgePropertyGroupForVertexChunk(pg0, vertex_chunk_index, false)
-    if (len == 1)
+    if (len == 1) {
       return df0
+    }
 
     var rdd = df0.rdd
     var schema_array = df0.schema.fields
@@ -204,13 +250,15 @@ class EdgeReader(prefix: String,  edgeInfo: EdgeInfo, adjListType: AdjListType.V
    */
   def readMultipleEdgePropertyGroups(propertyGroups: java.util.ArrayList[PropertyGroup], addIndex: Boolean = true): DataFrame = {
     val len: Int = propertyGroups.size
-    if (len == 0)
+    if (len == 0) {
       return spark.emptyDataFrame
+    }
 
     val pg0: PropertyGroup = propertyGroups.get(0)
     val df0 = readEdgePropertyGroup(pg0, false)
-    if (len == 1)
+    if (len == 1) {
       return df0
+    }
 
     var rdd = df0.rdd
     var schema_array = df0.schema.fields