NAVAND-1037 add streaming serialisation for DirectionsResponse (#1545)

Author: vadzim-vys

CHANGELOG.md

@@ -3,6 +3,7 @@
 Mapbox welcomes participation and contributions from everyone.
 
 ### main
+- Added `DirectionsResponse.fromJson(Reader)` and `DirectionsResponse.fromJson(Reader, RouteOptions)` to support streaming serialisation of `DirectionsResponse`.
 
 ### v6.11.0 - March 03, 2023
 - No additional changes

services-core/src/test/java/com/mapbox/core/TestUtils.java

@@ -8,9 +8,11 @@
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
+import java.io.InputStreamReader;
 import java.io.ObjectInputStream;
 import java.io.ObjectOutputStream;
 import java.io.Serializable;
+import java.nio.charset.StandardCharsets;
 import java.util.Scanner;
 
 import static java.nio.charset.StandardCharsets.UTF_8;
@@ -28,12 +30,20 @@ public void compareJson(String expectedJson, String actualJson) {
   }
 
   protected String loadJsonFixture(String filename) throws IOException {
-    ClassLoader classLoader = getClass().getClassLoader();
-    InputStream inputStream = classLoader.getResourceAsStream(filename);
+    InputStream inputStream = getResourceInputSteam(filename);
     Scanner scanner = new Scanner(inputStream, UTF_8.name()).useDelimiter("\\A");
     return scanner.hasNext() ? scanner.next() : "";
   }
 
+  protected InputStreamReader getResourceInputSteamReader(String filename) {
+    return new InputStreamReader(getResourceInputSteam(filename), StandardCharsets.UTF_8);
+  }
+
+  private InputStream getResourceInputSteam(String filename) {
+    ClassLoader classLoader = getClass().getClassLoader();
+    return classLoader.getResourceAsStream(filename);
+  }
+
   public static <T extends Serializable> byte[] serialize(T obj)
     throws IOException {
     ByteArrayOutputStream baos = new ByteArrayOutputStream();

services-directions-models/src/main/java/com/mapbox/api/directions/v5/models/DirectionsResponse.java

@@ -9,6 +9,8 @@
 import com.mapbox.api.directions.v5.DirectionsAdapterFactory;
 import com.mapbox.geojson.Point;
 import com.mapbox.geojson.PointAsCoordinatesTypeAdapter;
+
+import java.io.Reader;
 import java.util.ArrayList;
 import java.util.List;
 
@@ -139,11 +141,25 @@ public static TypeAdapter<DirectionsResponse> typeAdapter(Gson gson) {
    * @since 3.0.0
    */
   public static DirectionsResponse fromJson(@NonNull String json) {
-    GsonBuilder gson = new GsonBuilder();
-    gson.registerTypeAdapterFactory(DirectionsAdapterFactory.create());
-    gson.registerTypeAdapter(Point.class, new PointAsCoordinatesTypeAdapter());
     // rebuilding to ensure that underlying routes have assigned indices and UUID
-    return gson.create().fromJson(json, DirectionsResponse.class).toBuilder().build();
+    return createGson().fromJson(json, DirectionsResponse.class).toBuilder().build();
+  }
+
+  /**
+   * Deserializes a new instance of this class reading from the specified reader.
+   * <p>
+   * Consider using {@link #fromJson(Reader, RouteOptions)} if the result is used with
+   * downstream consumers of the directions models (like Mapbox Navigation SDK)
+   * to provide rerouting and route refreshing features.
+   *
+   * @param json a reader producing a valid JSON defining a GeoJson Directions Response
+   * @return a new instance of this class defined by the values passed inside this static factory
+   *   method
+   * @see #fromJson(Reader, RouteOptions)
+   */
+  public static DirectionsResponse fromJson(@NonNull Reader json) {
+    // rebuilding to ensure that underlying routes have assigned indices and UUID
+    return createGson().fromJson(json, DirectionsResponse.class).toBuilder().build();
   }
 
   /**
@@ -166,10 +182,7 @@ public static DirectionsResponse fromJson(@NonNull String json) {
   @Deprecated
   public static DirectionsResponse fromJson(
     @NonNull String json, @Nullable RouteOptions routeOptions, @Nullable String requestUuid) {
-    GsonBuilder gson = new GsonBuilder();
-    gson.registerTypeAdapterFactory(DirectionsAdapterFactory.create());
-    gson.registerTypeAdapter(Point.class, new PointAsCoordinatesTypeAdapter());
-    DirectionsResponse response = gson.create().fromJson(json, DirectionsResponse.class);
+    DirectionsResponse response = createGson().fromJson(json, DirectionsResponse.class);
     if (routeOptions != null) {
       response = response.updateWithRequestData(routeOptions);
     }
@@ -196,11 +209,33 @@ public static DirectionsResponse fromJson(
    * @see RouteOptions#fromJson(String)
    */
   public static DirectionsResponse fromJson(
-    @NonNull String json, @NonNull RouteOptions routeOptions) {
-    GsonBuilder gson = new GsonBuilder();
-    gson.registerTypeAdapterFactory(DirectionsAdapterFactory.create());
-    gson.registerTypeAdapter(Point.class, new PointAsCoordinatesTypeAdapter());
-    DirectionsResponse response = gson.create().fromJson(json, DirectionsResponse.class);
+    @NonNull String json,
+    @NonNull RouteOptions routeOptions
+  ) {
+    DirectionsResponse response = createGson().fromJson(json, DirectionsResponse.class);
+    // rebuilding to ensure that underlying routes have assigned indices and UUID
+    return response.updateWithRequestData(routeOptions);
+  }
+
+  /**
+   * Deserializes a new instance of this class reading from the specified reader.
+   * <p>
+   * The parameter of {@link RouteOptions} that were used to make the original route request
+   * which might be required by downstream consumers of the directions models
+   * (like Mapbox Navigation SDK) to provide rerouting and route refreshing features.
+   *
+   * @param json         a reader producing a valid JSON defining a GeoJson Directions Response
+   * @param routeOptions options that were used during the original route request
+   * @return a new instance of this class defined by the values passed inside this static factory
+   *   method
+   * @see RouteOptions#fromUrl(java.net.URL)
+   * @see RouteOptions#fromJson(String)
+   */
+  public static DirectionsResponse fromJson(
+    @NonNull Reader json,
+    @NonNull RouteOptions routeOptions
+  ) {
+    DirectionsResponse response = createGson().fromJson(json, DirectionsResponse.class);
     // rebuilding to ensure that underlying routes have assigned indices and UUID
     return response.updateWithRequestData(routeOptions);
   }
@@ -332,4 +367,11 @@ public DirectionsResponse build() {
       return autoBuild();
     }
   }
+
+  @NonNull private static Gson createGson() {
+    GsonBuilder gson = new GsonBuilder();
+    gson.registerTypeAdapterFactory(DirectionsAdapterFactory.create());
+    gson.registerTypeAdapter(Point.class, new PointAsCoordinatesTypeAdapter());
+    return gson.create();
+  }
 }

services-directions-models/src/test/java/com/mapbox/api/directions/v5/models/DirectionsResponseTest.java

@@ -8,16 +8,15 @@
 import com.mapbox.api.directions.v5.DirectionsCriteria;
 import com.mapbox.core.TestUtils;
 import com.mapbox.geojson.Point;
+import org.junit.Test;
 
 import java.io.IOException;
+import java.io.InputStreamReader;
+import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
-
-import org.junit.Test;
-
-import java.util.ArrayList;
 import java.util.Map;
 import java.util.Set;
 
@@ -83,6 +82,37 @@ public void fromJson_correctlyBuildsFromJson() throws Exception {
     assertEquals(1, response.routes().size());
   }
 
+  @Test
+  public void deserialization_from_reader() throws Exception {
+    String testJsonFileName = DIRECTIONS_V5_PRECISION6_FIXTURE;
+    String jsonText = loadJsonFixture(testJsonFileName);
+    InputStreamReader jsonReader = getResourceInputSteamReader(testJsonFileName);
+
+    DirectionsResponse responseFromReader = DirectionsResponse.fromJson(jsonReader);
+    DirectionsResponse responseFromText = DirectionsResponse.fromJson(jsonText);
+
+    assertEquals(responseFromText, responseFromReader);
+  }
+
+  @Test
+  public void deserialization_from_reader_with_route_options() throws Exception {
+    RouteOptions testRouteOptions = RouteOptions.builder()
+      .profile(DirectionsCriteria.PROFILE_DRIVING_TRAFFIC)
+      .coordinatesList(new ArrayList<Point>() {{
+        add(Point.fromLngLat(1.0, 1.0));
+        add(Point.fromLngLat(2.0, 2.0));
+      }})
+      .build();
+    String testJsonFileName = DIRECTIONS_V5_PRECISION6_FIXTURE;
+    InputStreamReader jsonReader = getResourceInputSteamReader(testJsonFileName);
+    String jsonText = loadJsonFixture(testJsonFileName);
+
+    DirectionsResponse responseFromReader = DirectionsResponse.fromJson(jsonReader, testRouteOptions);
+    DirectionsResponse responseFromText = DirectionsResponse.fromJson(jsonText, testRouteOptions);
+
+    assertEquals(responseFromText, responseFromReader);
+  }
+
   @Test
   public void testToFromJsonWithRealResponse() throws Exception {
     Gson gson = new GsonBuilder().create();