Add toJSON() and toMap() support to AccountOwnedModel superclass (#150)

This PR adds a new helper feature that allows all classes that extend AccountOwnedModel to serialize to either a JSON string or a Map representation of the object's fields.

Author: mrashed-dev

src/main/java/com/nylas/AccountOwnedModel.java

@@ -1,11 +1,30 @@
 package com.nylas;
 
+import java.util.Map;
+
 public abstract class AccountOwnedModel extends RestfulModel {
 
 	private String account_id;
 
 	public String getAccountId() {
 		return account_id;
 	}
+
+	/**
+	 * Converts the model to a JSON string
+	 * @return JSON string representation of the object
+	 */
+	public String toJSON() {
+		return JsonHelper.objectToJson(AccountOwnedModel.class, this);
+	}
+
+	/**
+	 * Converts the model to a Map
+	 * @return Map representation of the object
+	 */
+	@SuppressWarnings("unchecked")
+	public Map<String, ? extends AccountOwnedModel> toMap() {
+		return (Map<String, ? extends AccountOwnedModel>) JsonHelper.adapter(AccountOwnedModel.class).toJsonValue(this);
+	}
 
 }

src/main/java/com/nylas/JobStatus.java

@@ -107,6 +107,23 @@ public String getJobObjectId() {
 		return super.getId();
 	}
 
+	/**
+	 * {@inheritDoc}
+	 */
+	@Override
+	public String toJSON() {
+		return JsonHelper.objectToJson(JobStatus.class, this);
+	}
+
+	/**
+	 * {@inheritDoc}
+	 */
+	@SuppressWarnings("unchecked")
+	@Override
+	public Map<String, JobStatus> toMap() {
+		return (Map<String, JobStatus>) JsonHelper.adapter(JobStatus.class).toJsonValue(this);
+	}
+
 	@Override
 	public String toString() {
 		return "JobStatus [" +

src/main/java/com/nylas/JsonHelper.java

@@ -69,6 +69,10 @@ public static <T> T fromJsonUnchecked(JsonAdapter<T> adapter, String json) {
 	private static final JsonAdapter<List<Object>> listAdapter
 			= moshi.<List<Object>>adapter(List.class).indent("  ");
 
+	public static String objectToJson(Class<?> cls, Object obj) {
+		return adapter(cls).toJson(obj);
+	}
+
 	public static String mapToJson(Map<String, Object> map) {
 		return mapAdapter.toJson(map);
 	}

src/main/java/com/nylas/delta/Delta.java

@@ -41,6 +41,9 @@ public String toString() {
 	// Adapter for identifying the class of object in the delta to serialize to
 	public static final JsonAdapter.Factory ACCOUNT_OWNED_MODEL_JSON_FACTORY
 			= PolymorphicJsonAdapterFactory.of(AccountOwnedModel.class, "object")
+			.withSubtype(Account.class, "account")
+			.withSubtype(Calendar.class, "calendar")
+			.withSubtype(RoomResource.class, "room_resource")
 			.withSubtype(Contact.class, "contact")
 			.withSubtype(File.class, "file")
 			.withSubtype(Message.class, "message")