When we query our fences we only return the ids of the fences that were returned, therefore we need an endpoint to retrieve the metadata that corresponds to a fence id. This endpoint simply accepts an id, queries the Datastore and returns the metadata of the fence with the corresponding id.

getFenceById_snippet.java

@ApiMethod(name = "getById", httpMethod = "get", path = "getById")
public ArrayList < MyFence > getFenceById(@Named("group") String group, @Named("id") long id) {
	DatastoreService datastore = DatastoreServiceFactory.getDatastoreService();
	Key fenceKey = KeyFactory.createKey("Geofence", group);
	Filter propertyFilter = new FilterPredicate("id", FilterOperator.EQUAL, id);
	Query query = new Query("Fence", fenceKey).setFilter(propertyFilter);
	Entity fenceFromStore = datastore.prepare(query).asSingleEntity();
 
	ArrayList < MyFence > fences = new ArrayList < MyFence > ();
	if (fenceFromStore != null) {
		String name = (String) fenceFromStore.getProperty("name");
		String description = (String) fenceFromStore.getProperty("description");
		Gson gson = new Gson();
		Text vText = (Text) fenceFromStore.getProperty("vertices");
		String vString = vText.getValue();
		double[][] vertices = gson.fromJson(vString, double[][].class);
 
		MyFence tempFence = new MyFence(id, name, group, description, vertices);
		fences.add(tempFence);
	}
	return fences;
}