5 files changed, 20 insertions, 144 deletions
diff --git a/platform/android/src/style/conversion/function.hpp b/platform/android/src/style/conversion/function.hpp
index 510efd3c94..d6669b4508 100644
--- a/platform/android/src/style/conversion/function.hpp
+++ b/platform/android/src/style/conversion/function.hpp
@@ -7,7 +7,8 @@
 #include "../../java/lang.hpp"
 
 #include <jni/jni.hpp>
-#include "gson.hpp"
+#include "../../gson/json_element.hpp"
+
 #include <tuple>
 #include <map>
 
@@ -16,41 +17,32 @@ namespace android {
 namespace conversion {
 
 template <class T>
-struct Converter<jni::jobject*, mbgl::style::CameraFunction<T>> {
+struct Converter<jni::Object<android::gson::JsonElement>, mbgl::style::CameraFunction<T>> {
 
-    Result<jni::jobject*> operator()(jni::JNIEnv& env, const mbgl::style::CameraFunction<T>& value) const {
+    Result<jni::Object<android::gson::JsonElement>> operator()(jni::JNIEnv& env, const mbgl::style::CameraFunction<T>& value) const {
         // Convert expressions
         mbgl::Value expressionValue = value.getExpression().serialize();
-        JsonEvaluator jsonEvaluator{env};
-        jni::jobject* converted = apply_visitor(jsonEvaluator, expressionValue);
-
-        return converted;
+        return gson::JsonElement::New(env, expressionValue);
     }
 };
 
 template <class T>
-struct Converter<jni::jobject*, mbgl::style::SourceFunction<T>> {
+struct Converter<jni::Object<android::gson::JsonElement>, mbgl::style::SourceFunction<T>> {
 
-    Result<jni::jobject*> operator()(jni::JNIEnv& env, const mbgl::style::SourceFunction<T>& value) const {
+    Result<jni::Object<android::gson::JsonElement>> operator()(jni::JNIEnv& env, const mbgl::style::SourceFunction<T>& value) const {
         // Convert expressions
         mbgl::Value expressionValue = value.getExpression().serialize();
-        JsonEvaluator jsonEvaluator{env};
-        jni::jobject* converted = apply_visitor(jsonEvaluator, expressionValue);
-
-        return converted;
+        return gson::JsonElement::New(env, expressionValue);
     }
 };
 
 template <class T>
-struct Converter<jni::jobject*, mbgl::style::CompositeFunction<T>> {
+struct Converter<jni::Object<android::gson::JsonElement>, mbgl::style::CompositeFunction<T>> {
 
-    Result<jni::jobject*> operator()(jni::JNIEnv& env, const mbgl::style::CompositeFunction<T>& value) const {
+    Result<jni::Object<android::gson::JsonElement>> operator()(jni::JNIEnv& env, const mbgl::style::CompositeFunction<T>& value) const {
         // Convert expressions
         mbgl::Value expressionValue = value.getExpression().serialize();
-        JsonEvaluator jsonEvaluator{env};
-        jni::jobject* converted = apply_visitor(jsonEvaluator, expressionValue);
-
-        return converted;
+        return gson::JsonElement::New(env, expressionValue);
     }
 };
 
diff --git a/platform/android/src/style/conversion/gson.hpp b/platform/android/src/style/conversion/gson.hpp
deleted file mode 100644
index 02c3fdd30d..0000000000
--- a/platform/android/src/style/conversion/gson.hpp
+++ /dev/null
@@ -1,114 +0,0 @@
-#pragma once
-
-#include "../../conversion/constant.hpp"
-#include "../../conversion/collection.hpp"
-
-#include <mapbox/geometry.hpp>
-#include <jni/jni.hpp>
-#include "../../jni/local_object.hpp"
-#include "mapbox/geometry/feature.hpp"
-
-namespace mbgl {
-namespace android {
-namespace conversion {
-
-/**
- * Turn mapbox::geometry::value type into Java Json
- */
-class JsonEvaluator {
-public:
-
-    jni::JNIEnv& env;
-
-    jni::jobject* operator()(const mapbox::geometry::null_value_t) const {
-       return (jni::jobject*) nullptr;;
-    }
-
-    jni::jobject* operator()(const bool& value) const {
-        static jni::jclass* javaClass = jni::NewGlobalRef(env, &jni::FindClass(env, "com/google/gson/JsonPrimitive")).release();
-        static jni::jmethodID* constructor = &jni::GetMethodID(env, *javaClass, "<init>", "(Ljava/lang/Boolean;)V");
-
-        // Create JsonPrimitive
-        jni::LocalObject<jni::jobject> converted = jni::NewLocalObject(env, *convert<jni::jobject*, bool>(env, value));
-        jni::jobject* object = &jni::NewObject(env, *javaClass, *constructor, *converted);
-
-        return object;
-    }
-
-    template <class Number>
-    jni::jobject* operator()(const Number& value) const {
-        static jni::jclass* javaClass = jni::NewGlobalRef(env, &jni::FindClass(env, "com/google/gson/JsonPrimitive")).release();
-        static jni::jmethodID* constructor = &jni::GetMethodID(env, *javaClass, "<init>", "(Ljava/lang/Number;)V");
-
-        // Create JsonPrimitive
-        jni::LocalObject<jni::jobject> converted = jni::NewLocalObject(env, *convert<jni::jobject*, Number>(env, value));
-        jni::jobject* object = &jni::NewObject(env, *javaClass, *constructor, converted.get());
-
-        return object;
-    }
-
-    jni::jobject* operator()(const std::string value) const {
-        static jni::jclass* javaClass = jni::NewGlobalRef(env, &jni::FindClass(env, "com/google/gson/JsonPrimitive")).release();
-        static jni::jmethodID* constructor = &jni::GetMethodID(env, *javaClass, "<init>", "(Ljava/lang/String;)V");
-
-        // Create JsonPrimitive
-        jni::LocalObject<jni::jobject> converted = jni::NewLocalObject(env, *convert<jni::jobject*, std::string>(env, value));
-        jni::jobject* object = &jni::NewObject(env, *javaClass, *constructor, converted.get());
-
-        return object;
-    }
-
-    jni::jobject* operator()(const std::vector<mapbox::geometry::value> values) const {
-        static jni::jclass* javaClass = jni::NewGlobalRef(env, &jni::FindClass(env, "com/google/gson/JsonArray")).release();
-        static jni::jmethodID* constructor = &jni::GetMethodID(env, *javaClass, "<init>", "()V");;
-        static jni::jmethodID* add = &jni::GetMethodID(env, *javaClass, "add", "(Lcom/google/gson/JsonElement;)V");
-
-        // Create json array
-        jni::jobject* jarray = &jni::NewObject(env, *javaClass, *constructor);
-
-        // Add values
-        for (const auto &v : values) {
-            jni::LocalObject<jni::jobject> converted = jni::NewLocalObject(env, mapbox::geometry::value::visit(v, *this));
-            jni::CallMethod<void>(env, jarray, *add, converted.get());
-        }
-
-        return jarray;
-    }
-
-    jni::jobject* operator()(const std::unordered_map<std::string, mapbox::geometry::value> value) const {
-        static jni::jclass* javaClass = jni::NewGlobalRef(env, &jni::FindClass(env, "com/google/gson/JsonObject")).release();
-        static jni::jmethodID* constructor = &jni::GetMethodID(env, *javaClass, "<init>", "()V");;
-        static jni::jmethodID* add = &jni::GetMethodID(env, *javaClass, "add", "(Ljava/lang/String;Lcom/google/gson/JsonElement;)V");
-
-        // Create json object
-        jni::jobject* jsonObject = &jni::NewObject(env, *javaClass, *constructor);
-
-        // Add items
-        for (auto &item : value) {
-            jni::LocalObject<jni::jobject> converted = jni::NewLocalObject(env, mbgl::Value::visit(item.second, *this));
-            jni::LocalObject<jni::jobject> key = jni::NewLocalObject(env, *convert<jni::jobject*, std::string>(env, item.first));
-            jni::CallMethod<void>(env, jsonObject, *add, key.get(), converted.get());
-        }
-
-        return jsonObject;
-    }
-
-private:
-
-};
-
-/**
- * mapbox::geometry::value -> Java Json
- */
-template <>
-struct Converter<jni::jobject*, mapbox::geometry::value> {
-    Result<jni::jobject*> operator()(jni::JNIEnv& env, const mapbox::geometry::value& value) const {
-        JsonEvaluator evaluator { env } ;
-        jni::jobject* converted = mapbox::geometry::value::visit(value, evaluator);
-        return { converted };
-    }
-};
-
-}
-}
-}
diff --git a/platform/android/src/style/conversion/property_value.hpp b/platform/android/src/style/conversion/property_value.hpp
index 4ed25eac25..902d1e80b2 100644
--- a/platform/android/src/style/conversion/property_value.hpp
+++ b/platform/android/src/style/conversion/property_value.hpp
@@ -7,7 +7,6 @@
 #include "../../conversion/constant.hpp"
 #include "types.hpp"
 #include "function.hpp"
-#include "gson.hpp"
 
 namespace mbgl {
 namespace android {
@@ -32,15 +31,15 @@ public:
     }
 
     jni::jobject* operator()(const mbgl::style::CameraFunction<T> &value) const {
-        return *convert<jni::jobject*, mbgl::style::CameraFunction<T>>(env, value);
+        return *convert<jni::Object<android::gson::JsonElement>, mbgl::style::CameraFunction<T>>(env, value);
     }
 
     jni::jobject* operator()(const mbgl::style::SourceFunction<T> &value) const {
-        return *convert<jni::jobject*, mbgl::style::SourceFunction<T>>(env, value);
+        return *convert<jni::Object<android::gson::JsonElement>, mbgl::style::SourceFunction<T>>(env, value);
     }
 
     jni::jobject* operator()(const mbgl::style::CompositeFunction<T> &value) const {
-        return *convert<jni::jobject*, mbgl::style::CompositeFunction<T>>(env, value);
+        return *convert<jni::Object<android::gson::JsonElement>, mbgl::style::CompositeFunction<T>>(env, value);
     }
 
 private:
diff --git a/platform/android/src/style/layers/layer.cpp b/platform/android/src/style/layers/layer.cpp
index a2f4087fce..6fe6e3cb29 100644
--- a/platform/android/src/style/layers/layer.cpp
+++ b/platform/android/src/style/layers/layer.cpp
@@ -26,7 +26,6 @@
 // C++ -> Java conversion
 #include "../conversion/property_value.hpp"
 #include <mbgl/style/filter.hpp>
-#include "../conversion/gson.hpp"
 
 #include <string>
 
@@ -153,20 +152,19 @@ namespace android {
         }
     };
 
-    jni::Object<gson::JsonArray> Layer::getFilter(jni::JNIEnv& env) {
+    jni::Object<gson::JsonElement> Layer::getFilter(jni::JNIEnv& env) {
         using namespace mbgl::style;
         using namespace mbgl::style::conversion;
 
         Filter filter = layer.accept(GetFilterEvaluator());
 
-        jni::jobject* converted = nullptr;
+        jni::Object<gson::JsonElement> converted;
         if (filter.is<ExpressionFilter>()) {
             ExpressionFilter filterExpression = filter.get<ExpressionFilter>();
             mbgl::Value expressionValue = filterExpression.expression.get()->serialize();
-            conversion::JsonEvaluator jsonEvaluator{env};
-            converted = apply_visitor(jsonEvaluator, expressionValue);
+            converted = gson::JsonElement::New(env, expressionValue);
         }
-        return jni::Object<gson::JsonArray>(converted);
+        return converted;
     }
 
     struct SetSourceLayerEvaluator {
diff --git a/platform/android/src/style/layers/layer.hpp b/platform/android/src/style/layers/layer.hpp
index 19713a1baa..2486b0dfa6 100644
--- a/platform/android/src/style/layers/layer.hpp
+++ b/platform/android/src/style/layers/layer.hpp
@@ -5,6 +5,7 @@
 #include <mbgl/style/layer.hpp>
 #include "../../gson/json_array.hpp"
 #include "../value.hpp"
+#include "../../gson/json_element.hpp"
 
 #include <jni/jni.hpp>
 
@@ -68,7 +69,7 @@ public:
 
     void setFilter(jni::JNIEnv&, jni::Array<jni::Object<>>);
 
-    jni::Object<gson::JsonArray> getFilter(jni::JNIEnv&);
+    jni::Object<gson::JsonElement> getFilter(jni::JNIEnv&);
 
     void setSourceLayer(jni::JNIEnv&, jni::String);