Merge pull request #79 from uber/dataconverter

Add sample of Cadence data converter

Author: abhishekj720

src/main/java/com/uber/cadence/samples/spring/cadence/CadenceDataConverter.java

@@ -0,0 +1,22 @@
+package com.uber.cadence.samples.spring.cadence;
+
+import com.google.gson.TypeAdapterFactory;
+import com.uber.cadence.converter.JsonDataConverter;
+
+import java.time.ZonedDateTime;
+import java.util.ServiceLoader;
+
+// This singleton JsonDataConverter should be universally used in all components that require a
+// JsonDataConverter. Specifically in Cadence's case, WorkflowClient uses Json serialize function
+// and Worker uses deserialize function, therefore they have to match with one another.
+public class CadenceDataConverter {
+    public static JsonDataConverter cadenceJsonDataConverter() {
+        return new JsonDataConverter(
+                gsonBuilder -> {
+                    for (TypeAdapterFactory factory : ServiceLoader.load(TypeAdapterFactory.class)) {
+                        gsonBuilder.registerTypeAdapterFactory(factory);
+                    }
+                    return gsonBuilder.registerTypeAdapter(ZonedDateTime.class, new ZonedDatetimeConverter());
+                });
+    }
+}

src/main/java/com/uber/cadence/samples/spring/cadence/ZonedDatetimeConverter.java

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+package com.uber.cadence.samples.spring.cadence;
+
+import com.google.gson.JsonSerializer;
+import com.google.gson.JsonDeserializer;
+import com.google.gson.JsonElement;
+import com.google.gson.JsonSerializationContext;
+import com.google.gson.JsonPrimitive;
+import com.google.gson.JsonDeserializationContext;
+import com.google.gson.JsonParseException;
+
+import java.lang.reflect.Type;
+import java.time.ZonedDateTime;
+import java.time.format.DateTimeFormatter;
+
+public class ZonedDatetimeConverter implements JsonSerializer<ZonedDateTime>, JsonDeserializer<ZonedDateTime> {
+    private static final DateTimeFormatter FORMATTER = DateTimeFormatter.ISO_DATE_TIME;
+
+    @Override
+    public JsonElement serialize(ZonedDateTime src, Type type, JsonSerializationContext jsonSerializationContext) {
+       return new JsonPrimitive(FORMATTER.format(src));
+    }
+
+    @Override
+    public ZonedDateTime deserialize(JsonElement json, Type type, JsonDeserializationContext jsonDeserializationContext) throws JsonParseException {
+       return FORMATTER.parse(json.getAsString(), ZonedDateTime::from);
+    }
+}