[SPARK-14653][ML] Remove json4s from mllib-local

## What changes were proposed in this pull request?

This PR moves Vector.toJson/fromJson to ml.linalg.VectorEncoder under mllib/ to keep mllib-local's dependency minimal. The json encoding is used by Params. So we still need this feature in SPARK-14615, where we will switch to ml.linalg in spark.ml APIs.

## How was this patch tested?

Copied existing unit tests over.

cc; dbtsai

Author: Xiangrui Meng <meng@databricks.com>

Closes #12802 from mengxr/SPARK-14653.

1 files changed, 0 insertions, 17 deletions

diff --git a/mllib-local/src/test/scala/org/apache/spark/ml/linalg/VectorsSuite.scala b/mllib-local/src/test/scala/org/apache/spark/ml/linalg/VectorsSuite.scala
index 504be36413..887814b5e7 100644
--- a/mllib-local/src/test/scala/org/apache/spark/ml/linalg/VectorsSuite.scala
+++ b/mllib-local/src/test/scala/org/apache/spark/ml/linalg/VectorsSuite.scala
@@ -20,7 +20,6 @@ package org.apache.spark.ml.linalg
 import scala.util.Random
 
 import breeze.linalg.{squaredDistance => breezeSquaredDistance, DenseMatrix => BDM}
-import org.json4s.jackson.JsonMethods.{parse => parseJson}
 
 import org.apache.spark.ml.SparkMLFunSuite
 import org.apache.spark.ml.util.TestingUtils._
@@ -339,20 +338,4 @@ class VectorsSuite extends SparkMLFunSuite {
     assert(v.slice(Array(2, 0)) === new SparseVector(2, Array(0), Array(2.2)))
     assert(v.slice(Array(2, 0, 3, 4)) === new SparseVector(4, Array(0, 3), Array(2.2, 4.4)))
   }
-
-  test("toJson/fromJson") {
-    val sv0 = Vectors.sparse(0, Array.empty, Array.empty)
-    val sv1 = Vectors.sparse(1, Array.empty, Array.empty)
-    val sv2 = Vectors.sparse(2, Array(1), Array(2.0))
-    val dv0 = Vectors.dense(Array.empty[Double])
-    val dv1 = Vectors.dense(1.0)
-    val dv2 = Vectors.dense(0.0, 2.0)
-    for (v <- Seq(sv0, sv1, sv2, dv0, dv1, dv2)) {
-      val json = v.toJson
-      parseJson(json) // `json` should be a valid JSON string
-      val u = Vectors.fromJson(json)
-      assert(u.getClass === v.getClass, "toJson/fromJson should preserve vector types.")
-      assert(u === v, "toJson/fromJson should preserve vector values.")
-    }
-  }
 }