to improve performance do not use BigDecimal for rounding (#938)

Author: osana

services-geojson/src/main/java/com/mapbox/geojson/gson/BoundingBoxSerializer.java

@@ -8,6 +8,7 @@
 import com.mapbox.geojson.BoundingBox;
 import com.mapbox.geojson.Point;
 import com.mapbox.geojson.shifter.CoordinateShifterManager;
+import com.mapbox.geojson.utils.GeoJsonUtils;
 
 import java.lang.reflect.Type;
 import java.util.List;
@@ -48,8 +49,8 @@ public JsonElement serialize(BoundingBox src, Type typeOfSrc, JsonSerializationC
     List<Double> unshiftedCoordinates =
             CoordinateShifterManager.getCoordinateShifter().unshiftPoint(point);
 
-    bbox.add(new JsonPrimitive(unshiftedCoordinates.get(0)));
-    bbox.add(new JsonPrimitive(unshiftedCoordinates.get(1)));
+    bbox.add(new JsonPrimitive(GeoJsonUtils.trim(unshiftedCoordinates.get(0))));
+    bbox.add(new JsonPrimitive(GeoJsonUtils.trim(unshiftedCoordinates.get(1))));
     if (point.hasAltitude()) {
       bbox.add(new JsonPrimitive(unshiftedCoordinates.get(2)));
     }
@@ -58,8 +59,8 @@ public JsonElement serialize(BoundingBox src, Type typeOfSrc, JsonSerializationC
     point = src.northeast();
     unshiftedCoordinates =
             CoordinateShifterManager.getCoordinateShifter().unshiftPoint(point);
-    bbox.add(new JsonPrimitive(unshiftedCoordinates.get(0)));
-    bbox.add(new JsonPrimitive(unshiftedCoordinates.get(1)));
+    bbox.add(new JsonPrimitive(GeoJsonUtils.trim(unshiftedCoordinates.get(0))));
+    bbox.add(new JsonPrimitive(GeoJsonUtils.trim(unshiftedCoordinates.get(1))));
     if (point.hasAltitude()) {
       bbox.add(new JsonPrimitive(unshiftedCoordinates.get(2)));
     }

services-geojson/src/main/java/com/mapbox/geojson/gson/CoordinateTypeAdapter.java

@@ -5,10 +5,9 @@
 import com.google.gson.stream.JsonWriter;
 
 import com.mapbox.geojson.shifter.CoordinateShifterManager;
+import com.mapbox.geojson.utils.GeoJsonUtils;
 
 import java.io.IOException;
-import java.math.BigDecimal;
-import java.math.RoundingMode;
 import java.util.ArrayList;
 import java.util.List;
 
@@ -27,16 +26,8 @@ public void write(JsonWriter out, List<Double> value) throws IOException {
     List<Double> unshiftedCoordinates =
             CoordinateShifterManager.getCoordinateShifter().unshiftPoint(value);
 
-    BigDecimal lon = BigDecimal.valueOf(unshiftedCoordinates.get(0));
-    String lonString = lon.setScale(7, RoundingMode.HALF_UP)
-            .stripTrailingZeros().toPlainString();
-
-    BigDecimal lat = BigDecimal.valueOf(unshiftedCoordinates.get(1));
-    String latString = lat.setScale(7, RoundingMode.HALF_UP)
-            .stripTrailingZeros().toPlainString();
-
-    out.value(Double.valueOf(lonString));
-    out.value(Double.valueOf(latString));
+    out.value(GeoJsonUtils.trim(unshiftedCoordinates.get(0)));
+    out.value(GeoJsonUtils.trim(unshiftedCoordinates.get(1)));
 
     // Includes altitude
     if (value.size() > 2) {

services-geojson/src/main/java/com/mapbox/geojson/gson/PointSerializer.java

@@ -7,10 +7,9 @@
 import com.google.gson.JsonSerializer;
 import com.mapbox.geojson.Point;
 import com.mapbox.geojson.shifter.CoordinateShifterManager;
+import com.mapbox.geojson.utils.GeoJsonUtils;
 
 import java.lang.reflect.Type;
-import java.math.BigDecimal;
-import java.math.RoundingMode;
 import java.util.List;
 
 /**
@@ -50,16 +49,8 @@ public JsonElement serialize(Point src, Type typeOfSrc, JsonSerializationContext
     List<Double> unshiftedCoordinates =
             CoordinateShifterManager.getCoordinateShifter().unshiftPoint(src);
 
-    BigDecimal lon = BigDecimal.valueOf(unshiftedCoordinates.get(0));
-    String lonString = lon.setScale(7, RoundingMode.HALF_UP)
-      .stripTrailingZeros().toPlainString();
-
-    BigDecimal lat = BigDecimal.valueOf(unshiftedCoordinates.get(1));
-    String latString = lat.setScale(7, RoundingMode.HALF_UP)
-            .stripTrailingZeros().toPlainString();
-
-    rawCoordinates.add(new JsonPrimitive(Double.valueOf(lonString)));
-    rawCoordinates.add(new JsonPrimitive(Double.valueOf(latString)));
+    rawCoordinates.add(new JsonPrimitive(GeoJsonUtils.trim(unshiftedCoordinates.get(0))));
+    rawCoordinates.add(new JsonPrimitive(GeoJsonUtils.trim(unshiftedCoordinates.get(1))));
 
     // Includes altitude
     if (src.hasAltitude()) {

services-geojson/src/main/java/com/mapbox/geojson/utils/GeoJsonUtils.java

@@ -0,0 +1,25 @@
+package com.mapbox.geojson.utils;
+
+/**
+ * GeoJson utils class contains method that can be used throughout geojson package.
+ *
+ * @since 4.3.0
+ */
+public class GeoJsonUtils {
+
+  private static double ROUND_PRECISION = 10000000.0;
+  private static long MAX_DOUBLE_TO_ROUND = (long) (Long.MAX_VALUE / ROUND_PRECISION);
+
+  /**
+   * Trims a double value to have only 7 digits after period.
+   *
+   * @param value to be trimed
+   * @return trimmed value
+   */
+  public static double trim(double value) {
+    if (value > MAX_DOUBLE_TO_ROUND || value < -MAX_DOUBLE_TO_ROUND) {
+      return value;
+    }
+    return Math.round(value * ROUND_PRECISION) / ROUND_PRECISION;
+  }
+}

services-geojson/src/test/java/com/mapbox/geojson/utils/GeoJsonUtilsTest.java

@@ -0,0 +1,53 @@
+package com.mapbox.geojson.utils;
+
+import static org.junit.Assert.assertEquals;
+
+import com.mapbox.core.TestUtils;
+import org.junit.Test;
+
+
+public class GeoJsonUtilsTest extends TestUtils {
+
+
+  @Test
+  public void trimPositiveRoundUp() {
+    double trimmedValue = GeoJsonUtils.trim(3.123456789);
+    double expected = 3.1234568;
+    assertEquals("trim to 7 digits after period", expected, trimmedValue, 1e-8);
+  }
+
+  @Test
+  public void trimPositiveRoundDown() {
+    double trimmedValue = GeoJsonUtils.trim(3.123456712);
+    double expected = 3.1234567;
+    assertEquals("trim to 7 digits after period", expected, trimmedValue, 1e-8);
+  }
+
+  @Test
+  public void trimNegative() {
+    double trimmedValue = GeoJsonUtils.trim(-3.123456789);
+    double expected = -3.1234568;
+    assertEquals("trim to 7 digits after period", expected, trimmedValue, 1e-8);
+  }
+
+  @Test
+  public void trimZero() {
+    double trimmedValue = GeoJsonUtils.trim(0);
+    double expected = 0;
+    assertEquals("trim to 7 digits after period", expected, trimmedValue, 1e-8);
+  }
+
+  @Test
+  public void trimInt() {
+    double trimmedValue = GeoJsonUtils.trim(8);
+    double expected = 8;
+    assertEquals("trim to 7 digits after period", expected, trimmedValue, 1e-8);
+  }
+
+  @Test
+  public void trimMaxLong() {
+    double trimmedValue = GeoJsonUtils.trim(Long.MAX_VALUE + 0.1);
+    double expected = Long.MAX_VALUE;
+    assertEquals("trim to 7 digits after period", expected, trimmedValue, 1e-8);
+  }
+}