Statistics

Opencast provides an extensible mechanism to make statistics data available to the Opencast administrative user interface and also to third-party applications using the External API.

The overall idea is that sources of statistics data (StatisticsProvider) are managed at a central service (StatisticsService). The StatisticsService supports a minimal set of common attributes, in particular, the type of the StatisticsProvider which implies a data format and available parametrization.

A client can use the StatisticsService to retrieve a list of all available StatisticsProviders. The data format as well as the parameters supported by the StatisticsProviders are implied by the type of the provider. This information is used by the client to decide whether it can visualize the statistics data and which component has to be used for visualization.

Modules

The StatisticsService consists of the following modules:

• statistics-service-api An API module defining the core StatisticsService and StatisticsProvider functions.
• statistics-service-impl The default implementation of the StatisticsService as an OSGi service.
• statistics-service remote The remote implementation of the StatisticsService.
• statistics-provider-influx An implementation of the StatisticsProvider for InfluxDB
• statistics-provider-random An implementation of the StatisticsProvider for testing and demo purposes.

Interfaces & Classes

The Opencast StatisticsService implements the two interfaces StatisticsCoordinator and StatisticsService.

StatisticsCoordinator

This interface is used by StatisticsProvider implementations to register and unregister themselves at the statistics service.

Method	Description
addProvider	Register a statistics provider at the statistics service
removeProvider	Unregister a statistics provider from the statistics service

StatisticsService

This is the interface used by clients of the statistics service to retrieve a list of registered statistics providers

Method	Description
getProviders	Retrieve lists of statistics providers

StatisticsProvider

The StatisticsProvider interface provides access to common attributes of the statistics providers:

Method	Description
getId	Returns the unique identifier of the statistics provider
getType	Returns the type of the statistics provider
getResourceType	Returns the ResourceType of the statistics provider
getName	Returns the displayable name of the statistics provider
getDescription	Returns the displayable description of the statistics provider

whereas supported resource types are

ResourceType	Description
EPISODE	The statistics data relates to an episode
SERIES	The statistics data relates to a series
ORGANIZATION	The statistics data does not relate to a particular object

Integration

The StatisticsService API is supposed to be an internal Opencast interface. External clients can use the External API to access Opencast statistics and the Opencast Admin UI has access through the Admin UI facade.

External API

The External API supports Opencast statistics by its Statistics API endpoint.

Admin UI

The Admin UI supports Opencast statistics at various levels:

File	Description
modules/admin-ui/src/main/java/org/opencastproject/adminui/endpoint/StatisticsEndpoint.java	Implementation of the Statistics endpoint for the Admin UI facade
modules/admin-ui/src/main/webapp/scripts/shared/resources/statisticsResource.js	Abstracts StatisticsEndpoint for use in the web application