[android] bindings for aggregated cluster properties

platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/style/expressions/Expression.java

@@ -1435,6 +1435,27 @@ public static Expression id() {
     return new Expression("id");
   }
 
+  /**
+   * Gets the value of a cluster property accumulated so far. Can only be used in the clusterProperties
+   * option of a clustered GeoJSON source.
+   * <p>
+   * Example usage:
+   * </p>
+   * <pre>
+   * {@code
+   *  GeoJsonOptions options = new GeoJsonOptions()
+   *                              .withCluster(true)
+   *                              .withClusterProperty("max", max(accumulated(), get("max")).toArray(), get("mag").toArray());
+   * }
+   * </pre>
+   *
+   * @return expression
+   * @see <a href="https://www.mapbox.com/mapbox-gl-js/style-spec/#expressions-accumulated">Style specification</a>
+   */
+  public static Expression accumulated() {
+    return new Expression("accumulated");
+  }
+
   /**
    * Gets the kernel density estimation of a pixel in a heatmap layer,
    * which is a relative measure of how many data points are crowded around a particular pixel.

platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/style/sources/GeoJsonOptions.java

@@ -109,4 +109,33 @@ public GeoJsonOptions withClusterRadius(int clusterRadius) {
     this.put("clusterRadius", clusterRadius);
     return this;
   }
+
+  /**
+   * An object defining custom properties on the generated clusters if clustering is enabled,
+   * aggregating values from clustered points. Has the form {"property_name": [operator, [map_expression]]} or
+   * {"property_name": [[operator, accumulated, expression], [map_expression]]}
+   *
+   * @param propertyName name of the property
+   * @param operator operator is any expression function that accepts at least 2 operands (e.g. "+" or "max") - it
+   *                 accumulates the property value from clusters/points the cluster contains. It can either be a
+   *                 string with single operator, or be an object array converted from valid expression
+   * @param mapExpr map expression produces the value of a single point, it shall be an object array, which is
+   *                converted from a valid expression
+   * @return the current instance for chaining
+   */
+  @NonNull
+  public GeoJsonOptions withClusterProperty(String propertyName, Object operator, Object mapExpr) {
+    if (this.containsKey("clusterProperties")) {
+      HashMap<String, Object[]> properties = (HashMap<String, Object[]>)(this.get("clusterProperties"));
+      properties.put(propertyName, new Object[]{operator, mapExpr});
+      properties.put(propertyName, new Object[]{operator, mapExpr});
+      this.put("clusterProperties", properties);
+    } else {
+      HashMap<String, Object[]> properties = new HashMap<String, Object[]>();
+      properties.put(propertyName, new Object[]{operator, mapExpr});
+      properties.put(propertyName, new Object[]{operator, mapExpr});
+      this.put("clusterProperties", properties);
+    }
+    return this;
+  }
 }

platform/android/MapboxGLAndroidSDKTestApp/src/main/java/com/mapbox/mapboxsdk/testapp/activity/style/GeoJsonClusteringActivity.java

@@ -30,6 +30,8 @@
 import java.util.Objects;
 
 import static com.mapbox.mapboxsdk.style.expressions.Expression.all;
+import static com.mapbox.mapboxsdk.style.expressions.Expression.accumulated;
+import static com.mapbox.mapboxsdk.style.expressions.Expression.concat;
 import static com.mapbox.mapboxsdk.style.expressions.Expression.division;
 import static com.mapbox.mapboxsdk.style.expressions.Expression.exponential;
 import static com.mapbox.mapboxsdk.style.expressions.Expression.get;
@@ -39,6 +41,8 @@
 import static com.mapbox.mapboxsdk.style.expressions.Expression.interpolate;
 import static com.mapbox.mapboxsdk.style.expressions.Expression.literal;
 import static com.mapbox.mapboxsdk.style.expressions.Expression.lt;
+import static com.mapbox.mapboxsdk.style.expressions.Expression.max;
+import static com.mapbox.mapboxsdk.style.expressions.Expression.neq;
 import static com.mapbox.mapboxsdk.style.expressions.Expression.rgb;
 import static com.mapbox.mapboxsdk.style.expressions.Expression.stop;
 import static com.mapbox.mapboxsdk.style.expressions.Expression.toNumber;
@@ -138,6 +142,9 @@ private GeoJsonSource createClusterSource() throws URISyntaxException {
       .withCluster(true)
       .withClusterMaxZoom(14)
       .withClusterRadius(50)
+      .withClusterProperty("max", max(accumulated(), get("max")).toArray(), get("mag").toArray())
+      .withClusterProperty("sum", "+", get("mag").toArray())
+      .withClusterProperty("felt", "any", neq(get("felt"), literal("null")).toArray())
     );
   }
 
@@ -182,9 +189,9 @@ private CircleLayer createClusterLevelLayer(int level, int[][] layerColors) {
   }
 
   private SymbolLayer createClusterTextLayer() {
-    return new SymbolLayer("count", "earthquakes")
+    return new SymbolLayer("property", "earthquakes")
       .withProperties(
-        textField(Expression.toString(get("point_count"))),
+        textField(concat(get("point_count"), literal(", "), get("max"))),
         textSize(12f),
         textColor(Color.WHITE),
         textIgnorePlacement(true),

platform/android/src/java_types.cpp

@@ -18,6 +18,10 @@ namespace java {
 
     jni::jclass* Map::jclass;
     jni::jmethodID* Map::getMethodId;
+    jni::jmethodID* Map::keySetMethodId;
+
+    jni::jclass* Set::jclass;
+    jni::jmethodID* Set::toArrayMethodId;
 
     void registerNatives(JNIEnv& env) {
         ObjectArray::jclass = jni::NewGlobalRef(env, &jni::FindClass(env, "[Ljava/lang/Object;")).release();
@@ -34,6 +38,10 @@ namespace java {
 
         Map::jclass = jni::NewGlobalRef(env, &jni::FindClass(env, "java/util/Map")).release();
         Map::getMethodId = &jni::GetMethodID(env, *Map::jclass, "get", "(Ljava/lang/Object;)Ljava/lang/Object;");
+        Map::keySetMethodId = &jni::GetMethodID(env, *Map::jclass, "keySet", "()Ljava/util/Set;");
+
+        Set::jclass = jni::NewGlobalRef(env, &jni::FindClass(env, "java/util/Set")).release();
+        Set::toArrayMethodId = &jni::GetMethodID(env, *Set::jclass, "toArray", "()[Ljava/lang/Object;");
     }
 
 }

platform/android/src/java_types.hpp

@@ -29,6 +29,12 @@ namespace java {
     struct Map {
         static jni::jclass* jclass;
         static jni::jmethodID* getMethodId;
+        static jni::jmethodID* keySetMethodId;
+    };
+
+    struct Set {
+        static jni::jclass* jclass;
+        static jni::jmethodID* toArrayMethodId;
     };
 
     void registerNatives(JNIEnv&);

platform/android/src/style/android_conversion.hpp

@@ -47,9 +47,18 @@ class ConversionTraits<mbgl::android::Value> {
     }
 
     template <class Fn>
-    static optional<Error> eachMember(const mbgl::android::Value&, Fn&&) {
-        // TODO
-        mbgl::Log::Warning(mbgl::Event::Android, "eachMember not implemented");
+    static optional<Error> eachMember(const mbgl::android::Value& value, Fn&& fn) {
+        assert(value.isObject());
+        mbgl::android::Value keys = value.keyArray();
+        std::size_t length = arrayLength(keys);
+        for(std::size_t i = 0; i < length; ++i){
+            const auto k = keys.get(i).toString();
+            auto v = value.get(k.c_str());
+            optional<Error> result = fn(k, std::move(v));
+            if (result) {
+                return result;
+            }
+        }
         return {};
     }
 

platform/android/src/style/value.cpp

@@ -63,6 +63,12 @@ namespace android {
         return Value(env, jni::Local<jni::Object<>>(env, member));
     }
 
+    Value Value::keyArray() const{
+        jni::jobject* set = jni::CallMethod<jni::jobject*>(env, value.get(), *java::Map::keySetMethodId);
+        jni::jobject* array = jni::CallMethod<jni::jobject*>(env, set, *java::Set::toArrayMethodId);
+        return Value(env, jni::Local<jni::Object<>>(env, array));
+    }
+
     int Value::getLength() const {
         auto array = (jni::jarray<jni::jobject>*) value.get();
         return jni::GetArrayLength(env, *array);

platform/android/src/style/value.hpp

@@ -31,6 +31,7 @@ class Value {
     long toLong() const;
     bool toBool() const;
     Value get(const char* key) const;
+    Value keyArray() const;
     int getLength() const;
     Value get(const int index ) const;