[android] Minimal Android support for 'format' expression

- No dedicated support for creating format expressions
- Java accessors for 'text-field' flatten back to String
- 'text-field' setter implicitly creates a 'format' expression. For tests, use JsonArray to build an equivalent format expression by hand.

4 files changed, 69 insertions, 2 deletions

diff --git a/platform/android/MapboxGLAndroidSDKTestApp/src/androidTest/java/com/mapbox/mapboxsdk/testapp/style/SymbolLayerTest.java b/platform/android/MapboxGLAndroidSDKTestApp/src/androidTest/java/com/mapbox/mapboxsdk/testapp/style/SymbolLayerTest.java
index 98c9c27fc2..7026e87a47 100644
--- a/platform/android/MapboxGLAndroidSDKTestApp/src/androidTest/java/com/mapbox/mapboxsdk/testapp/style/SymbolLayerTest.java
+++ b/platform/android/MapboxGLAndroidSDKTestApp/src/androidTest/java/com/mapbox/mapboxsdk/testapp/style/SymbolLayerTest.java
@@ -13,6 +13,8 @@ import com.mapbox.mapboxsdk.testapp.activity.BaseActivityTest;
 
 import org.junit.Test;
 import org.junit.runner.RunWith;
+import com.google.gson.JsonArray;
+import com.google.gson.JsonObject;
 
 import static com.mapbox.mapboxsdk.style.expressions.Expression.*;
 import static com.mapbox.mapboxsdk.testapp.action.MapboxMapAction.invoke;
@@ -477,7 +479,18 @@ public class SymbolLayerTest extends BaseActivityTest {
       assertEquals((String) layer.getTextField().getValue(), (String) "");
 
       layer.setProperties(textField("{token}"));
-      assertEquals(layer.getTextField().getExpression(), Expression.toString(Expression.get("token")));
+      JsonArray formatExpression = new JsonArray();
+      formatExpression.add("format");
+      JsonArray getExpression = new JsonArray();
+      getExpression.add("get");
+      getExpression.add("token");
+      JsonArray stringCoercion = new JsonArray();
+      stringCoercion.add("to-string");
+      stringCoercion.add(getExpression);
+      formatExpression.add(stringCoercion);
+      formatExpression.add(new JsonObject());
+      assertEquals(layer.getTextField().getExpression(),
+         Converter.convert(formatExpression));
     });
   }
 
@@ -490,7 +503,17 @@ public class SymbolLayerTest extends BaseActivityTest {
       assertNotNull(layer);
 
       // Set and Get
-      Expression expression = string(Expression.get("undefined"));
+      JsonArray formatExpression = new JsonArray();
+      formatExpression.add("format");
+      JsonArray getExpression = new JsonArray();
+      getExpression.add("get");
+      getExpression.add("undefined");
+      JsonArray stringAssertion = new JsonArray();
+      stringAssertion.add("string");
+      stringAssertion.add(getExpression);
+      formatExpression.add(stringAssertion);
+      formatExpression.add(new JsonObject());
+      Expression expression = Converter.convert(formatExpression);
       layer.setProperties(textField(expression));
       assertEquals(layer.getTextField().getExpression(), expression);
     });
diff --git a/platform/android/MapboxGLAndroidSDKTestApp/src/androidTest/java/com/mapbox/mapboxsdk/testapp/style/layer.junit.ejs b/platform/android/MapboxGLAndroidSDKTestApp/src/androidTest/java/com/mapbox/mapboxsdk/testapp/style/layer.junit.ejs
index 142d1bd203..e78620d1b7 100644
--- a/platform/android/MapboxGLAndroidSDKTestApp/src/androidTest/java/com/mapbox/mapboxsdk/testapp/style/layer.junit.ejs
+++ b/platform/android/MapboxGLAndroidSDKTestApp/src/androidTest/java/com/mapbox/mapboxsdk/testapp/style/layer.junit.ejs
@@ -17,6 +17,10 @@ import com.mapbox.mapboxsdk.testapp.activity.BaseActivityTest;
 
 import org.junit.Test;
 import org.junit.runner.RunWith;
+<% if (type === 'symbol') { -%>
+import com.google.gson.JsonArray;
+import com.google.gson.JsonObject;
+<% } -%>
 
 import static com.mapbox.mapboxsdk.style.expressions.Expression.*;
 import static com.mapbox.mapboxsdk.testapp.action.MapboxMapAction.invoke;
@@ -165,8 +169,23 @@ public class <%- camelize(type) %>LayerTest extends BaseActivityTest {
 <% if (property.tokens) { -%>
 
       layer.setProperties(<%- camelizeWithLeadingLowercase(property.name) %>("{token}"));
+<% if (property.type === 'formatted') { -%>
+      JsonArray formatExpression = new JsonArray();
+      formatExpression.add("format");
+      JsonArray getExpression = new JsonArray();
+      getExpression.add("get");
+      getExpression.add("token");
+      JsonArray stringCoercion = new JsonArray();
+      stringCoercion.add("to-string");
+      stringCoercion.add(getExpression);
+      formatExpression.add(stringCoercion);
+      formatExpression.add(new JsonObject());
+      assertEquals(layer.getTextField().getExpression(),
+         Converter.convert(formatExpression));
+<% } else { -%>
       assertEquals(layer.get<%- camelize(property.name) %>().getExpression(), Expression.toString(Expression.get("token")));
 <% } -%>
+<% } -%>
     });
   }
 <% if (property['property-type'] === 'data-driven' || property['property-type'] === 'cross-faded-data-driven') { -%>
@@ -181,7 +200,21 @@ public class <%- camelize(type) %>LayerTest extends BaseActivityTest {
       assertNotNull(layer);
 
       // Set and Get
+<% if (property.type === 'formatted') { -%>
+      JsonArray formatExpression = new JsonArray();
+      formatExpression.add("format");
+      JsonArray getExpression = new JsonArray();
+      getExpression.add("get");
+      getExpression.add("undefined");
+      JsonArray stringAssertion = new JsonArray();
+      stringAssertion.add("string");
+      stringAssertion.add(getExpression);
+      formatExpression.add(stringAssertion);
+      formatExpression.add(new JsonObject());
+      Expression expression = Converter.convert(formatExpression);
+<% } else { -%>
       Expression expression = <%- defaultExpressionJava(property) %>(Expression.get("undefined"));
+<% } -%>
       layer.setProperties(<%- camelizeWithLeadingLowercase(property.name) %>(expression));
       assertEquals(layer.get<%- camelize(property.name) %>().getExpression(), expression);
     });
diff --git a/platform/android/src/conversion/constant.cpp b/platform/android/src/conversion/constant.cpp
index 804d5fd146..eaff434dbc 100644
--- a/platform/android/src/conversion/constant.cpp
+++ b/platform/android/src/conversion/constant.cpp
@@ -29,6 +29,10 @@ Result<jni::Local<jni::Object<>>> Converter<jni::Local<jni::Object<>>, Color>::o
     return jni::Make<jni::String>(env, sstream.str());
 }
 
+Result<jni::Local<jni::Object<>>> Converter<jni::Local<jni::Object<>>, style::expression::Formatted>::operator()(jni::JNIEnv& env, const style::expression::Formatted& value) const {
+    return jni::Make<jni::String>(env, value.toString());
+}
+
 Result<jni::Local<jni::Object<>>> Converter<jni::Local<jni::Object<>>, std::vector<std::string>>::operator()(jni::JNIEnv& env, const std::vector<std::string>& value) const {
     auto result = jni::Array<jni::String>::New(env, value.size());
 
diff --git a/platform/android/src/conversion/constant.hpp b/platform/android/src/conversion/constant.hpp
index c6dafe1174..4def670f3c 100644
--- a/platform/android/src/conversion/constant.hpp
+++ b/platform/android/src/conversion/constant.hpp
@@ -5,6 +5,8 @@
 #include <mbgl/util/color.hpp>
 #include <mbgl/util/enum.hpp>
 
+#include <mbgl/style/expression/formatted.hpp>
+
 #include <jni/jni.hpp>
 
 #include <string>
@@ -53,6 +55,11 @@ struct Converter<jni::Local<jni::Object<>>, Color> {
     Result<jni::Local<jni::Object<>>> operator()(jni::JNIEnv& env, const Color& value) const;
 };
 
+template <>
+struct Converter<jni::Local<jni::Object<>>, style::expression::Formatted> {
+    Result<jni::Local<jni::Object<>>> operator()(jni::JNIEnv& env, const style::expression::Formatted& value) const;
+};
+
 template <std::size_t N>
 struct Converter<jni::Local<jni::Object<>>, std::array<float, N>> {
     Result<jni::Local<jni::Object<>>> operator()(jni::JNIEnv& env, const std::array<float, N>& value) const {