Periodic is a component for visualizing recurring data. Features: The graph is given the maximum value that will be found in the data items e.g. if working with monthly occurrences it would be 31 or with hours in a day then the given value would be 24. The component works as a layout and can be given Vaadin components that will be added vertically below the graph part of the component. But the main recommendation would be to not use it as a layout. Data Items and paintables: The base add-on contains 2 item types PeriodicItem and Split. PeriodicItem contains data for one item instance and is drawn to given length and gets the added label. Split is used to create a visual split (vertical line) with text (inside line not as a bottom label) and contains no data. Custom Item Implementations can be made Required on the Server Side: To create your own items all you need to do on the server side if you want to have a periodic data item is to implement the [Periodical] interface. If the item only wants to be drawn then no server side extensions or implementations are needed. Required on the Client Side: On the client side there are 3 interfaces that can be implemented. To not have the component evaluate the custom item as any Vaadin component the widget should implement the [PeriodicPaintable] interface. To get drag events to position the component the [PeriodicMovable] interface should be implemented. Then if the component is a periodic data item then the [PeriodicalItem] interface should be implemented. Data estimation: When having enough data (basically 3 or more periods) the component can when given an Estimate.class implementation fill in empty future items with estimated occurrences. The existing estimators are Mean and Median that just take the mean or median value of the "empty" and "actual" data in the given set. Estimation can be much more flexible and targeted for data as the Estimator implementation is given the "actual" data as a int list in the order they come up and the same for the "empty" data. Also the whole dataset is collected for the estimator to use as a **EstimateData** list that contains the `DataType` and the length of the data and is in the order they appear. Estimation is done with the command `periodic.estimateOccurrences(Median.class);`