Fixes clj-java transformation bugs

Fixes the transformation from clj to java for the sum of squares
(in numeric targets) and fixes transformations for group targets.

project.clj

@@ -1,4 +1,4 @@
-(defproject histogram "2.0.0"
+(defproject histogram "2.0.1"
   :description "Dynamic/streaming histograms"
   :source-path "src/clj"
   :java-source-path "src/java"

src/clj/histogram/core.clj

@@ -38,16 +38,15 @@
   (instance? Histogram hist))
 
 (defn- java-target [target]
-  (let [target-val (or (:sum target) (:counts target))
-        missing-count (:missing-count target)]
-    (cond (number? target-val)
-          (NumericTarget. target-val missing-count)
-          (map? target-val)
-          (MapCategoricalTarget. (HashMap. target-val) missing-count)
-          (sequential? target-val)
-          (GroupTarget. (ArrayList. (map java-target target-val)))
-          (nil? target)
-          SimpleTarget/TARGET)))
+  (if (sequential? target)
+    (GroupTarget. (ArrayList. (map java-target target)))
+    (let [{:keys [sum sum-squares missing-count counts]} target]
+      (cond (contains? target :sum)
+            (NumericTarget. sum sum-squares missing-count)
+            (contains? target :counts)
+            (MapCategoricalTarget. (HashMap. counts) missing-count)
+            (nil? target)
+            SimpleTarget/TARGET))))
 
 (defn- java-bin [bin]
   (let [{:keys [mean count target]} bin]
@@ -275,7 +274,8 @@
                    {:max-bins (.getMaxBins hist)
                     :gap-weighted? (.isCountWeightedGaps hist)
                     :freeze (.getFreezeThreshold hist)
-                    :group-types (seq (.getGroupTypes hist))
+                    :group-types (map (comp keyword str)
+                                      (seq (.getGroupTypes hist)))
                     :categories (seq (.getTargetCategories hist))
                     :bins (bins hist)
                     :missing-bin (when (pos? (.getMissingCount hist))

src/java/com/bigml/histogram/NumericTarget.java

@@ -5,8 +5,8 @@
 import org.json.simple.JSONArray;
 
 public class NumericTarget extends Target<NumericTarget> {
-  
-  private NumericTarget(Double target, Double sumSquares, double missingCount) {
+
+  public NumericTarget(Double target, Double sumSquares, double missingCount) {
     _sum = target;
     _sumSquares = sumSquares;
     _missingCount = missingCount;
@@ -19,7 +19,7 @@ public NumericTarget(Double target, double missingCount) {
     }
     _missingCount = missingCount;
   }
-  
+
   public NumericTarget(Double target) {
     this(target, target == null ? 1 : 0);
   }
@@ -41,7 +41,7 @@ public double getMissingCount() {
   public TargetType getTargetType() {
     return Histogram.TargetType.numeric;
   }
-  
+
   @Override
   public String toString() {
     return String.valueOf(_sum) + "," + String.valueOf(_sumSquares);
@@ -56,7 +56,7 @@ protected void addJSON(JSONArray binJSON, DecimalFormat format) {
       binJSON.add(Double.valueOf(format.format(_sumSquares)));
     }
   }
-  
+
   @Override
   protected NumericTarget init() {
     return new NumericTarget(0d);
@@ -83,7 +83,7 @@ protected NumericTarget sum(NumericTarget target) {
     _missingCount += target.getMissingCount();
     return this;
   }
-  
+
   @Override
   protected NumericTarget mult(double multiplier) {
     if (_sum != null) {

test/histogram/test/core.clj

@@ -256,6 +256,12 @@
     (is (== 5 (maximum merged)))))
 
 (deftest transform-test
+  (let [hist (-> (create)
+                 (insert! 1 [2 3 :a])
+                 (insert! 1 [9 2 :b])
+                 (insert! 4 [5 nil nil]))]
+    (is (= (hist-to-clj hist)
+           (hist-to-clj (clj-to-hist (hist-to-clj hist))))))
   (let [hist1 (reduce (fn [h [x y]] (insert! h x y))
                       (create :bins 8 :gap-weighted? true
                               :categories [:apple :orange :grape])