IPluginSelector interface
The IPluginSelector interface can be implemented to select a particular implementation of a plugin (out of several implementations) based on the business scenario. For example, say there exists two sites one for Business to Consumer (B2C) and another for Business to Business (B2B).
Say for B2C the default implementation of a particular plugin is sufficient, however, for B2B it need to be modified. In this scenario, there exists two concrete implementations of the given plugin, and the implementation to use depends on the business case: whether the website is B2B or B2C.
"Plugin" class attribute
First step to different concrete implementations of the same plugin is to decorate the plugin with the "Plugin" class attribute. All the default plugins in Litium Studio have this attribute set to "Default". If a implementation exists without this attribute, it is given priority below the implementation which has "Default" attribute and will probably not be used.
To have different concrete implementations of the same plugin, implement the IPluginSelector interface.
The GetPluginName<T>() method should return the "Plugin" class attribute placed to the custom concrete implementation.
IPluginSelector implementation
In the concrete implemenation of IPluginSelector, return the same name as specified in the above "Plugin" attribute shown above to execute that concrete implementation of the plugin.
Example:
In the case of Litium Accelerators, the website has a settings page which has a property called AcceleratorType, which is either "B2B", "B2C", ..., and based on the website selects the correct plugin to use. If the settings page is not found, it returns "Default" to make the default plugin to take effect.
StateTransitions Plugin can have only one concrete implementation
Note that the plugin selector will not work correctly if the plugin is invoked from the Litium Studio back-office in the above case, because it depends on the current website, and there is no current website in back-office.
For this reason, you should not override the StateTransitions plugin using the above method. There should be only one implementation of the StateTransitions plugin, but the implementation can have customized sections based on the website.