[android] url getter on sources

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

@@ -227,6 +227,14 @@ public class GeoJsonSource extends Source {
     nativeSetUrl(url);
   }
 
+  /**
+   * @return The url or null
+   */
+  @Nullable
+  public String getUrl() {
+    return nativeGetUrl();
+  }
+
   /**
    * Queries the source for features.
    *
@@ -243,6 +251,8 @@ public class GeoJsonSource extends Source {
 
   protected native void nativeSetUrl(String url);
 
+  protected native String nativeGetUrl();
+
   private native void nativeSetGeoJsonString(String geoJson);
 
   private native void nativeSetFeatureCollection(FeatureCollection geoJson);

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

@@ -1,5 +1,7 @@
 package com.mapbox.mapboxsdk.style.sources;
 
+import android.support.annotation.Nullable;
+
 import java.net.URL;
 
 /**
@@ -72,8 +74,19 @@ public class RasterSource extends Source {
     initialize(id, tileSet.toValueObject(), tileSize);
   }
 
+  /**
+   * @return The url or null
+   */
+  @Nullable
+  public String getUrl() {
+    return nativeGetUrl();
+  }
+
   protected native void initialize(String layerId, Object payload, int tileSize);
 
   @Override
   protected native void finalize() throws Throwable;
+
+  protected native String nativeGetUrl();
+
 }

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

@@ -76,11 +76,21 @@ public class VectorSource extends Source {
     return features != null ? Arrays.asList(features) : new ArrayList<Feature>();
   }
 
+  /**
+   * @return The url or null
+   */
+  @Nullable
+  public String getUrl() {
+    return nativeGetUrl();
+  }
+
   protected native void initialize(String layerId, Object payload);
 
   @Override
   protected native void finalize() throws Throwable;
 
+  protected native String nativeGetUrl();
+
   private native Feature[] querySourceFeatures(String[] sourceLayerId,
                                                Object[] filter);