Rework expression conversion (#11490)

* [android] - rework expression conversion

1 files changed, 80 insertions, 0 deletions

diff --git a/platform/android/src/gson/json_primitive.cpp b/platform/android/src/gson/json_primitive.cpp
index 58d0b45fe7..4e171c4845 100644
--- a/platform/android/src/gson/json_primitive.cpp
+++ b/platform/android/src/gson/json_primitive.cpp
@@ -1,9 +1,89 @@
 #include "json_primitive.hpp"
+#include "../java/lang.hpp"
 
 namespace mbgl {
 namespace android {
 namespace gson {
 
+/**
+ * Turn mapbox::geometry::value into Java Gson JsonPrimitives
+ */
+class JsonPrimitiveEvaluator {
+public:
+
+    jni::JNIEnv& env;
+
+    /**
+     * Create a null primitive
+     */
+    jni::Object<JsonPrimitive> operator()(const mapbox::geometry::null_value_t) const {
+        return jni::Object<JsonPrimitive>();
+    }
+
+    /**
+     * Create a primitive containing a string value
+     */
+    jni::Object<JsonPrimitive> operator()(const std::string value) const {
+        static auto constructor = JsonPrimitive::javaClass.GetConstructor<jni::String>(env);
+        auto jvalue = jni::Make<jni::String>(env, value);
+        auto jsonPrimitive = JsonPrimitive::javaClass.New(env, constructor, jvalue);
+        jni::DeleteLocalRef(env, jvalue);
+        return jsonPrimitive;
+    }
+
+    /**
+     * Create a primitive containing a number value with type double
+     */
+    jni::Object<JsonPrimitive> operator()(const double value) const {
+        static auto constructor = JsonPrimitive::javaClass.GetConstructor<jni::Object<java::lang::Number>>(env);
+        auto boxedValue = java::lang::Double::valueOf(env, value);
+        auto number = jni::Cast(env, boxedValue, java::lang::Number::javaClass);
+        auto jsonPrimitive = JsonPrimitive::javaClass.New(env, constructor, number);
+        jni::DeleteLocalRef(env, boxedValue);
+        return jsonPrimitive;
+    }
+
+    /**
+     * Create a primitive containing a number value with type long
+     */
+    jni::Object<JsonPrimitive> operator()(const int64_t value) const {
+        static auto constructor = JsonPrimitive::javaClass.GetConstructor<jni::Object<java::lang::Number>>(env);
+        auto boxedValue = java::lang::Long::valueOf(env, value);
+        auto number = jni::Cast(env, boxedValue, java::lang::Number::javaClass);
+        auto jsonPrimitive =  JsonPrimitive::javaClass.New(env, constructor, number);
+        jni::DeleteLocalRef(env, boxedValue);
+        return jsonPrimitive;
+    }
+
+    /**
+     * Create a primitive containing a number value with type long
+     */
+    jni::Object<JsonPrimitive> operator()(const uint64_t value) const {
+        static auto constructor = JsonPrimitive::javaClass.GetConstructor<jni::Object<java::lang::Number>>(env);
+        auto boxedValue = java::lang::Long::valueOf(env, value);
+        auto number = jni::Cast(env, boxedValue, java::lang::Number::javaClass);
+        auto jsonPrimitive = JsonPrimitive::javaClass.New(env, constructor, number);
+        jni::DeleteLocalRef(env, boxedValue);
+        return jsonPrimitive;
+    }
+
+    /**
+     * Create a primitive containing a boolean value
+     */
+    jni::Object<JsonPrimitive> operator()(const bool value) const {
+        static auto constructor = JsonPrimitive::javaClass.GetConstructor<jni::Object<java::lang::Boolean>>(env);
+        auto boxedValue = java::lang::Boolean::valueOf(env, value);
+        auto jsonPrimitive = JsonPrimitive::javaClass.New(env, constructor, boxedValue);
+        jni::DeleteLocalRef(env, boxedValue);
+        return jsonPrimitive;
+    }
+};
+
+jni::Object<JsonPrimitive> JsonPrimitive::New(jni::JNIEnv &env, const value& value) {
+    JsonPrimitiveEvaluator evaluator { env };
+    return value::visit(value, evaluator);
+}
+
 JsonPrimitive::value JsonPrimitive::convert(jni::JNIEnv &env, jni::Object<JsonPrimitive> jsonPrimitive) {
     value value;
     if (jsonPrimitive) {