changed JSONArray -> interface Collection to catch all use-cases

json-path/src/main/java/com/jayway/jsonpath/internal/function/Length.java

@@ -5,9 +5,7 @@ import com.jayway.jsonpath.internal.EvaluationContext;
 import com.jayway.jsonpath.internal.PathRef;
 import net.minidev.json.JSONArray;
 
-import java.util.HashMap;
-import java.util.LinkedHashMap;
-import java.util.Map;
+import java.util.*;
 
 /**
  * Provides the length of a JSONArray Object
@@ -18,9 +16,8 @@ public class Length implements Function {
 
     @Override
     public Object invoke(String currentPath, PathRef parent, Object model, EvaluationContext ctx) {
-        if (model instanceof JSONArray) {
-            JSONArray array = (JSONArray)model;
-            return Integer.valueOf(array.size());
+        if (model instanceof Collection) {
+            return Integer.valueOf(((Collection) model).size());
         }
         else if (model instanceof Map) {
             return Integer.valueOf(((Map) model).size());