Applying patch for LIBRARIES-2720 (#517)

* Created ISO8601InstantAdapter.java file

* Fixed CI errors

* Spotless Fix

* Changed version in pom.xml

* Revert - Changed version in pom.xml because of failing test cases

---------

Co-authored-by: Michael Grosse Huelsewiesche <mihuelsewiesche@twilio.com>

Author: neelkanth-kaushik

analytics-core/src/main/java/com/segment/analytics/gson/ISO8601InstantAdapter.java

@@ -0,0 +1,37 @@
+package com.segment.analytics.gson;
+
+import com.google.gson.*;
+import com.google.gson.stream.JsonReader;
+import com.google.gson.stream.JsonWriter;
+import java.io.IOException;
+import java.lang.reflect.Type;
+import java.time.Instant;
+
+/**
+ * A {@link JsonSerializer} that formats {@link Instant} objects into iso8601 formatted strings, and
+ * {@link JsonDeserializer} that parses iso8601 formatted strings into {@link Instant} objects.
+ */
+public class ISO8601InstantAdapter extends TypeAdapter<Instant>
+    implements JsonSerializer<Instant>, JsonDeserializer<Instant> {
+  @Override
+  public JsonElement serialize(Instant src, Type typeOfSrc, JsonSerializationContext context) {
+    return new JsonPrimitive(Iso8601Utils.format(src)); // ISO 8601 format
+  }
+
+  @Override
+  public Instant deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext context)
+      throws JsonParseException {
+    return Instant.parse(json.getAsString());
+  }
+
+  @Override
+  public void write(JsonWriter out, Instant value) throws IOException {
+    out.value(value == null ? null : value.toString());
+  }
+
+  @Override
+  public Instant read(JsonReader in) throws IOException {
+    String str = in.nextString();
+    return str == null ? null : Instant.parse(str);
+  }
+}

analytics-core/src/main/java/com/segment/analytics/gson/Iso8601Utils.java

@@ -16,6 +16,7 @@
 package com.segment.analytics.gson;
 
 import com.google.gson.JsonParseException;
+import java.time.Instant;
 import java.util.Calendar;
 import java.util.Date;
 import java.util.GregorianCalendar;
@@ -277,4 +278,10 @@ private static int indexOfNonDigit(String string, int offset) {
     }
     return string.length();
   }
+
+  /** Returns {@code date} formatted as yyyy-MM-ddThh:mm:ss.sssZ */
+  static String format(Instant instant) {
+    // Format the instant
+    return String.valueOf(instant.getEpochSecond());
+  }
 }

analytics/src/main/java/com/segment/analytics/Analytics.java

@@ -4,11 +4,13 @@
 import com.google.gson.GsonBuilder;
 import com.segment.analytics.gson.AutoValueAdapterFactory;
 import com.segment.analytics.gson.ISO8601DateAdapter;
+import com.segment.analytics.gson.ISO8601InstantAdapter;
 import com.segment.analytics.http.SegmentService;
 import com.segment.analytics.internal.AnalyticsClient;
 import com.segment.analytics.internal.AnalyticsVersion;
 import com.segment.analytics.messages.Message;
 import com.segment.analytics.messages.MessageBuilder;
+import java.time.Instant;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
@@ -362,6 +364,7 @@ public Analytics build() {
 
       gsonBuilder
           .registerTypeAdapterFactory(new AutoValueAdapterFactory())
+          .registerTypeAdapter(Instant.class, new ISO8601InstantAdapter())
           .registerTypeAdapter(Date.class, new ISO8601DateAdapter());
 
       Gson gson = gsonBuilder.create();