Updating GraphX programming guide and documentation

This pull request revises the programming guide to reflect changes in the GraphX API as well as the deprecated mapReduceTriplets operator.

Author: Joseph E. Gonzalez <joseph.e.gonzalez@gmail.com>

Closes #3359 from jegonzal/GraphXProgrammingGuide and squashes the following commits:

4421964 [Joseph E. Gonzalez] updating documentation for graphx

1 files changed, 46 insertions, 0 deletions

diff --git a/graphx/src/main/scala/org/apache/spark/graphx/TripletFields.java b/graphx/src/main/scala/org/apache/spark/graphx/TripletFields.java
index 34df4b7ee7..8dfccfe2e2 100644
--- a/graphx/src/main/scala/org/apache/spark/graphx/TripletFields.java
+++ b/graphx/src/main/scala/org/apache/spark/graphx/TripletFields.java
@@ -24,10 +24,17 @@ import java.io.Serializable;
  * system to populate only those fields for efficiency.
  */
 public class TripletFields implements Serializable {
+
+  /** Indicates whether the source vertex attribute is included. */
   public final boolean useSrc;
+
+  /** Indicates whether the destination vertex attribute is included. */
   public final boolean useDst;
+
+  /** Indicates whether the edge attribute is included. */
   public final boolean useEdge;
 
+  /** Constructs a default TripletFields in which all fields are included. */
   public TripletFields() {
     this(true, true, true);
   }
@@ -38,14 +45,53 @@ public class TripletFields implements Serializable {
     this.useEdge = useEdge;
   }
 
+  /**
+   * None of the triplet fields are exposed.
+   */
   public static final TripletFields None = new TripletFields(false, false, false);
+
+  /**
+   * Expose only the edge field and not the source or destination field.
+   */
   public static final TripletFields EdgeOnly = new TripletFields(false, false, true);
+
+  /**
+   * Expose only the source field and not the edge or destination field.
+   */
   public static final TripletFields SrcOnly = new TripletFields(true, false, false);
+
+  /**
+   * Expose only the destination field and not the edge or source field.
+   */
   public static final TripletFields DstOnly = new TripletFields(false, true, false);
+
+  /**
+   * Expose the source and destination fields but not the edge field.
+   */
   public static final TripletFields SrcDstOnly = new TripletFields(true, true, false);
+
+  /**
+   * Expose the source and edge fields but not the destination field. (Same as Src)
+   */
   public static final TripletFields SrcAndEdge = new TripletFields(true, false, true);
+
+  /**
+   * Expose the source and edge fields but not the destination field. (Same as SrcAndEdge)
+   */
   public static final TripletFields Src = SrcAndEdge;
+
+  /**
+   * Expose the destination and edge fields but not the source field. (Same as Dst)
+   */
   public static final TripletFields DstAndEdge = new TripletFields(false, true, true);
+
+  /**
+   * Expose the destination and edge fields but not the source field. (Same as DstAndEdge)
+   */
   public static final TripletFields Dst = DstAndEdge;
+
+  /**
+   * Expose all the fields (source, edge, and destination).
+   */
   public static final TripletFields All = new TripletFields(true, true, true);
 }