Add ability to sort mixed-type lists to JsonSlurper

CHANGELOG.md

@@ -66,6 +66,8 @@ Current
 
 - [#45, removing sorting from weight check queries](https://github.com/yahoo/fili/pull/46)
 
+- `JsonSlurper` can now handle sorting lists with mixed-type entries, even if the list starts with a string, number, or
+  boolean
 
 ### Known Issues:
 

fili-core/src/test/java/com/yahoo/bard/webservice/util/JsonSlurper.java

@@ -5,6 +5,7 @@
 /*
  * Changed HashMap to LinkedHashMap for consistency. Added ability to optionally sort the lists and maps.
  */
+
 import static groovy.json.JsonTokenType.CLOSE_BRACKET;
 import static groovy.json.JsonTokenType.CLOSE_CURLY;
 import static groovy.json.JsonTokenType.COLON;
@@ -50,7 +51,7 @@
 @SuppressWarnings({ "rawtypes", "javadoc", "unchecked" })
 public class JsonSlurper {
 
-    private final Comparator<Map> mapComparator;
+    private final Comparator<Object> variableTypedComparator;
 
     private final JsonSortStrategy sortStrategy;
 
@@ -71,17 +72,17 @@ public JsonSlurper() {
      * @param sortStrategy  Strategy to use when sorting the parsed JSON object
      */
     public JsonSlurper(JsonSortStrategy sortStrategy) {
-        this(sortStrategy, new ToStringComparator<Map>());
+        this(sortStrategy, new ToStringComparator<>());
     }
 
     /**
      * Create a new JsonSlurper with the given sort strategy and map comparator.
      *
      * @param sortStrategy  Strategy to use when sorting the parsed JSON object
-     * @param mapComparator  Comparator to use when sorting a list of maps
+     * @param variableTypedComparator  Comparator to use when sorting a list with variable types
      */
-    public JsonSlurper(JsonSortStrategy sortStrategy, Comparator<Map> mapComparator) {
-        this.mapComparator = mapComparator;
+    public JsonSlurper(JsonSortStrategy sortStrategy, Comparator<Object> variableTypedComparator) {
+        this.variableTypedComparator = variableTypedComparator;
         this.sortStrategy = sortStrategy;
         switch (sortStrategy) {
             case SORT_BOTH:
@@ -103,8 +104,8 @@ public JsonSlurper(JsonSortStrategy sortStrategy, Comparator<Map> mapComparator)
         }
     }
 
-    public Comparator<Map> getMapComparator() {
-        return mapComparator;
+    public Comparator<Object> getVariableTypedComparator() {
+        return variableTypedComparator;
     }
 
     public JsonSortStrategy getSortStrategy() {
@@ -126,11 +127,16 @@ public boolean getSortMaps() {
      */
     private void sortIfNeeded(List listToSort) {
         if (sortLists) {
-            // Sort by the native compareTo if available, otherwise just sort by hash code to ensure consistent sorting
-            if (listToSort.size() > 0 && listToSort.get(0) instanceof Comparable) {
-                Collections.sort(listToSort);
+            // Sort by the native compareTo, otherwise just sort by the object comparator to ensure consistent sorting
+            if (listToSort.stream().anyMatch(it -> it instanceof Comparable)) {
+                try {
+                    Collections.sort(listToSort);
+                } catch (ClassCastException ignored) {
+                    // Failed to sort a consistently typed list of Comparables. Fall back to the collection comparator
+                    Collections.sort(listToSort, variableTypedComparator);
+                }
             } else {
-                Collections.sort(listToSort, mapComparator);
+                Collections.sort(listToSort, variableTypedComparator);
             }
         }
     }