1 files changed, 114 insertions, 0 deletions
diff --git a/platform/android/src/style/conversion/json.hpp b/platform/android/src/style/conversion/json.hpp
new file mode 100644
index 0000000000..c2ab4e360d
--- /dev/null
+++ b/platform/android/src/style/conversion/json.hpp
@@ -0,0 +1,114 @@
+#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};
+    }
+};
+
+}
+}
+}