Optimize Memory Usage by Interning Frequently Occurring Strings in JS…

…ON (#1585) * Intern IntersectionLanes's indication strings to save memory. * Optimize StepManeuver json parsing
mapbox · Jul 8, 2024 · 05a7bfe · 05a7bfe
1 parent be2ba14
commit 05a7bfe
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Showing 7 changed files with 294 additions and 2 deletions.
diff --git a/...irections-models/src/main/java/com/mapbox/api/directions/v5/models/IntersectionLanes.java b/...irections-models/src/main/java/com/mapbox/api/directions/v5/models/IntersectionLanes.java
@@ -109,7 +109,7 @@ public static Builder builder() {
    * @since 3.0.0
    */
   public static TypeAdapter<IntersectionLanes> typeAdapter(Gson gson) {
-    return new AutoValue_IntersectionLanes.GsonTypeAdapter(gson);
+    return new IntersectionLanesTypeAdapter(new AutoValue_IntersectionLanes.GsonTypeAdapter(gson));
   }
 
   /**

diff --git a/...odels/src/main/java/com/mapbox/api/directions/v5/models/IntersectionLanesTypeAdapter.java b/...odels/src/main/java/com/mapbox/api/directions/v5/models/IntersectionLanesTypeAdapter.java
@@ -0,0 +1,91 @@
+package com.mapbox.api.directions.v5.models;
+
+import com.google.gson.JsonElement;
+import com.google.gson.JsonObject;
+import com.google.gson.JsonParser;
+import com.google.gson.TypeAdapter;
+import com.google.gson.stream.JsonReader;
+import com.google.gson.stream.JsonToken;
+import com.google.gson.stream.JsonWriter;
+import com.mapbox.api.directions.v5.utils.ParseUtils;
+
+import java.io.IOException;
+import java.util.LinkedHashMap;
+import java.util.Map;
+
+/**
+ * A TypeAdapter for {@link IntersectionLanes} used to optimize JSON deserialization.
+ *
+ * <p>Strings in {@link IntersectionLanes#indications()} and
+ * {@link IntersectionLanes#validIndication()} can accept a limited set of possible values
+ * (e.g., "straight," "right," "left," etc.).
+ * This adapter invokes {@link String#intern()} on these strings to save memory.</p>
+ */
+class IntersectionLanesTypeAdapter extends TypeAdapter<IntersectionLanes> {
+
+  private final TypeAdapter<IntersectionLanes> defaultAdapter;
+
+  IntersectionLanesTypeAdapter(TypeAdapter<IntersectionLanes> defaultAdapter) {
+    this.defaultAdapter = defaultAdapter;
+  }
+
+  @Override
+  public void write(JsonWriter out, IntersectionLanes value) throws IOException {
+    defaultAdapter.write(out, value);
+  }
+
+  @Override
+  public IntersectionLanes read(JsonReader in) throws IOException {
+    if (in.peek() == JsonToken.NULL) {
+      in.nextNull();
+      return null;
+    }
+
+    final JsonObject jsonObject = JsonParser.parseReader(in).getAsJsonObject();
+
+    final IntersectionLanes.Builder builder = IntersectionLanes.builder();
+    Map<String, JsonElement> unrecognized = null;
+
+    for (Map.Entry<String, JsonElement> entry : jsonObject.entrySet()) {
+      final String key = entry.getKey();
+      final JsonElement value = entry.getValue();
+
+      if (value.isJsonNull()) {
+        continue;
+      }
+
+      switch (key) {
+        case "valid":
+          builder.valid(value.getAsBoolean());
+          break;
+
+        case "active":
+          builder.active(value.getAsBoolean());
+          break;
+
+        case "valid_indication":
+          builder.validIndication(value.getAsString().intern());
+          break;
+
+        case "indications":
+          builder.indications(ParseUtils.parseAndInternJsonStringArray(value.getAsJsonArray()));
+          break;
+
+        case "payment_methods":
+          builder.paymentMethods(ParseUtils.parseAndInternJsonStringArray(value.getAsJsonArray()));
+          break;
+
+        default:
+          if (unrecognized == null) {
+            unrecognized = new LinkedHashMap<>();
+          }
+          unrecognized.put(key, value);
+          break;
+      }
+    }
+
+    return builder
+      .unrecognizedJsonProperties(unrecognized)
+      .build();
+  }
+}
diff --git a/...ces-directions-models/src/main/java/com/mapbox/api/directions/v5/models/StepManeuver.java b/...ces-directions-models/src/main/java/com/mapbox/api/directions/v5/models/StepManeuver.java
@@ -301,7 +301,7 @@ public Point location() {
    * @since 3.0.0
    */
   public static TypeAdapter<StepManeuver> typeAdapter(Gson gson) {
-    return new AutoValue_StepManeuver.GsonTypeAdapter(gson);
+    return new StepManeuverTypeAdapter(new AutoValue_StepManeuver.GsonTypeAdapter(gson));
   }
 
   /**

diff --git a/...ons-models/src/main/java/com/mapbox/api/directions/v5/models/StepManeuverTypeAdapter.java b/...ons-models/src/main/java/com/mapbox/api/directions/v5/models/StepManeuverTypeAdapter.java
@@ -0,0 +1,102 @@
+package com.mapbox.api.directions.v5.models;
+
+import com.google.gson.JsonArray;
+import com.google.gson.JsonElement;
+import com.google.gson.JsonObject;
+import com.google.gson.JsonParser;
+import com.google.gson.TypeAdapter;
+import com.google.gson.stream.JsonReader;
+import com.google.gson.stream.JsonToken;
+import com.google.gson.stream.JsonWriter;
+
+import java.io.IOException;
+import java.util.LinkedHashMap;
+import java.util.Map;
+
+/**
+ * A TypeAdapter for {@link StepManeuver} used to optimize JSON deserialization.
+ *
+ * <p>Strings {@link StepManeuver#type()} and {@link StepManeuver#modifier()} can accept
+ * a limited set of possible values.
+ * This adapter invokes {@link String#intern()} on these strings to save memory.</p>
+ */
+class StepManeuverTypeAdapter extends TypeAdapter<StepManeuver> {
+  private final TypeAdapter<StepManeuver> defaultAdapter;
+
+  StepManeuverTypeAdapter(TypeAdapter<StepManeuver> defaultAdapter) {
+    this.defaultAdapter = defaultAdapter;
+  }
+
+  @Override
+  public void write(JsonWriter out, StepManeuver value) throws IOException {
+    defaultAdapter.write(out, value);
+  }
+
+  @Override
+  public StepManeuver read(JsonReader in) throws IOException {
+    if (in.peek() == JsonToken.NULL) {
+      in.nextNull();
+      return null;
+    }
+
+    final JsonObject jsonObject = JsonParser.parseReader(in).getAsJsonObject();
+
+    final StepManeuver.Builder builder = StepManeuver.builder();
+    Map<String, JsonElement> unrecognized = null;
+
+    for (Map.Entry<String, JsonElement> entry : jsonObject.entrySet()) {
+      final String key = entry.getKey();
+      final JsonElement value = entry.getValue();
+
+      if (value.isJsonNull()) {
+        continue;
+      }
+
+      switch (key) {
+        case "location":
+          final JsonArray jsonArray = value.getAsJsonArray();
+          final double[] locations = new double[jsonArray.size()];
+          for (int i = 0; i < jsonArray.size(); ++i) {
+            locations[i] = jsonArray.get(i).getAsDouble();
+          }
+          builder.rawLocation(locations);
+          break;
+
+        case "bearing_before":
+          builder.bearingBefore(value.getAsDouble());
+          break;
+
+        case "bearing_after":
+          builder.bearingAfter(value.getAsDouble());
+          break;
+
+        case "instruction":
+          builder.instruction(value.getAsString());
+          break;
+
+        case "type":
+          builder.type(value.getAsString().intern());
+          break;
+
+        case "modifier":
+          builder.modifier(value.getAsString().intern());
+          break;
+
+        case "exit":
+          builder.exit(value.getAsInt());
+          break;
+
+        default:
+          if (unrecognized == null) {
+            unrecognized = new LinkedHashMap<>();
+          }
+          unrecognized.put(key, value);
+          break;
+      }
+    }
+
+    return builder
+      .unrecognizedJsonProperties(unrecognized)
+      .build();
+  }
+}
diff --git a/services-directions-models/src/main/java/com/mapbox/api/directions/v5/utils/ParseUtils.java b/services-directions-models/src/main/java/com/mapbox/api/directions/v5/utils/ParseUtils.java
@@ -2,6 +2,8 @@
 
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
+
+import com.google.gson.JsonArray;
 import com.mapbox.api.directions.v5.models.Bearing;
 import com.mapbox.geojson.Point;
 import java.util.ArrayList;
@@ -213,4 +215,19 @@ public static List<Bearing> parseBearings(@Nullable String original) {
   public static List<Boolean> parseToBooleans(@Nullable String original) {
     return parseToList(SEMICOLON, original, BOOLEAN_PARSER);
   }
+
+  /**
+   * Parses strings from json array and invokes {@link String#intern()} on each item.
+   *
+   * @param jsonArray json array with string items
+   * @return List of interned parsed strings
+   */
+  @NonNull
+  public static List<String> parseAndInternJsonStringArray(JsonArray jsonArray) {
+    final List<String> result = new ArrayList<>(jsonArray.size());
+    for (int i = 0; i < jsonArray.size(); ++i) {
+      result.add(jsonArray.get(i).getAsString().intern());
+    }
+    return result;
+  }
 }
diff --git a/...tions-models/src/test/java/com/mapbox/api/directions/v5/models/IntersectionLanesTest.java b/...tions-models/src/test/java/com/mapbox/api/directions/v5/models/IntersectionLanesTest.java
@@ -2,6 +2,7 @@
 
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertSame;
 
 import com.mapbox.api.directions.v5.DirectionsCriteria;
 import com.mapbox.core.TestUtils;
@@ -102,4 +103,46 @@ public void testFromJson_etc2Payment() {
 
     assertEquals(intersectionLanes, intersectionLanesFromJson);
   }
+
+  @Test
+  public void testIndicationsAreInterned() {
+    IntersectionLanes intersectionLanes = IntersectionLanes.builder()
+      .validIndication("straight")
+      .indications(Arrays.asList("straight","straight"))
+      .build();
+
+    IntersectionLanes deserialized = IntersectionLanes.fromJson(
+      intersectionLanes.toJson()
+    );
+
+    List<String> indications = deserialized.indications();
+    assertEquals(Arrays.asList("straight","straight"), indications);
+    assertEquals("straight", deserialized.validIndication());
+
+    assertSame(indications.get(0), indications.get(1));
+    assertSame(indications.get(0), deserialized.validIndication());
+  }
+
+  @Test
+  public void testPaymentMethodsAreInterned() {
+    List<String> paymentMethods = Arrays.asList(
+      DirectionsCriteria.PAYMENT_METHOD_GENERAL,
+      DirectionsCriteria.PAYMENT_METHOD_GENERAL
+    );
+
+    IntersectionLanes intersectionLanes = IntersectionLanes.builder()
+      .paymentMethods(paymentMethods)
+      .build();
+
+    IntersectionLanes deserialized = IntersectionLanes.fromJson(
+      intersectionLanes.toJson()
+    );
+
+    assertEquals(paymentMethods, deserialized.paymentMethods());
+
+    assertSame(
+      deserialized.paymentMethods().get(0),
+      deserialized.paymentMethods().get(1)
+    );
+  }
 }
diff --git a/...directions-models/src/test/java/com/mapbox/api/directions/v5/models/StepManeuverTest.java b/...directions-models/src/test/java/com/mapbox/api/directions/v5/models/StepManeuverTest.java
@@ -2,6 +2,7 @@
 
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertSame;
 
 import com.mapbox.core.TestUtils;
 import com.mapbox.geojson.Point;
@@ -71,4 +72,42 @@ public void testFromJson() {
 
     compareJson(stepManeuverJsonString, jsonStr);
   }
+
+  @Test
+  public void testTypesAreInterned() {
+    StepManeuver stepManeuver1 = StepManeuver.builder()
+      .rawLocation(new double[] {1.0, 2.0})
+      .type(StepManeuver.TURN)
+      .build();
+
+    StepManeuver stepManeuver2 = StepManeuver.builder()
+      .rawLocation(new double[] {1.0, 3.0})
+      .type(StepManeuver.TURN)
+      .build();
+
+    StepManeuver deserialized1 = StepManeuver.fromJson(stepManeuver1.toJson());
+    StepManeuver deserialized2 = StepManeuver.fromJson(stepManeuver2.toJson());
+
+    assertEquals(deserialized1.type(), deserialized2.type());
+    assertSame(deserialized1.type(), deserialized2.type());
+  }
+
+  @Test
+  public void testModifierAreInterned() {
+    StepManeuver stepManeuver1 = StepManeuver.builder()
+      .rawLocation(new double[] {1.0, 2.0})
+      .modifier("slight right")
+      .build();
+
+    StepManeuver stepManeuver2 = StepManeuver.builder()
+      .rawLocation(new double[] {1.0, 3.0})
+      .modifier("slight right")
+      .build();
+
+    StepManeuver deserialized1 = StepManeuver.fromJson(stepManeuver1.toJson());
+    StepManeuver deserialized2 = StepManeuver.fromJson(stepManeuver2.toJson());
+
+    assertEquals(deserialized1.modifier(), deserialized2.modifier());
+    assertSame(deserialized1.modifier(), deserialized2.modifier());
+  }
 }