Cache Startup Loader and Refresher Components

Note

This feature is only available in NCache Enterprise Edition.

ICacheLoader Interface

To configure Cache Startup Loader and Refresher, ICacheLoader interface needs to be implemented and then configured using NCache Web Manager or PowerShell tool. NCache uses this custom provider to load and refresh data from the configured data source.

Important

Make sure that the NCache Loader Service is running and the firewall is disabled.

The class implementing this interface allows NCache to load data from the master data source to the cache. Therefore, this class needs to implement the logic for loading the required data from your data source. The following methods are required to be defined by the classes implementing loader and refresher:

Member	Type	Description
Init	void	This method is called by NCache on startup, and takes as input an IDictionary/Map of parameters which can be passed while configuring cache loader/refresher. Please refer to Configure Cache Startup Loader and Refresher in Administrators' Guide to understand how to configure cache loader/refresher in NCache. Through the input param, you can specify runtime parameters to your deployed provider like connection string etc.
LoadDatasetOnStartup	object	LoadDatasetOnStartup contains the logic to load data from the master data source and returns a user context object. This method takes string dataset that includes the data to be loaded in the cache. This data is then loaded in the cache and the UserContext can be used to track loaded data.
RefreshDataset	object	RefreshDataset contains the logic to refresh data that has been loaded in the cache. This method takes the UserContext returned by LoadDatasetOnStartup to understand which data it needs to refresh. When invoked, this method fetches fresh data from the data source based on the user context it receives.
GetDatasetToRefresh	Dictionary	GetDatasetToRefresh takes user context and iterates over it to assign RefreshPreference to each item in the dataset. It returns a Dictionary containing data to refresh with respective refresh interval.

cache-loader tag

Note that the datasets are specified through NCache Web Manager as explained in Administrators’ Guide. NCache adds these datasets under the <cache-loader> tag into config.ncconf, which are then fetched in the client application.

<cache-loader retries="0" retry-interval="0" enabled="True" refresh-on-event="False" refresh-interval="15">
      <provider assembly-name="Loader, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null" class-name="Loader.Loader" full-name="Loader.dll"/>
      <parameters name="connString" value="abc"/>
      <datasets>
        <dataset name="products" schedule-expression="0:1,5:12:00" schedule-option="Weekly"/>
        <dataset name="orders" schedule-expression="0:00:00:20" schedule-option="DailyInterval"/>
        <dataset name="customers" schedule-expression="0:00:00:00" schedule-option="DailyTime"/>
        <dataset name="stock" schedule-expression="0:1,15,L:10:00" schedule-option="Monthly"/>
        <dataset name="discount" schedule-expression="1,L:5,6:09:52" schedule-option="Monthly"/>
        <dataset name="sale" schedule-expression="" schedule-option=""/>
      </datasets>
    </cache-loader>

Properties	Description
retries	Number of retries to perform any failed operation before the next operation.
retry-interval	The time interval between each retry attempt to perform the failed operation.
enabled	Determines whether /refresher is enabled or not.
refresh-on-event	Determines whether to enable/disable poll-based refreshing.
refresh-interval	The time interval after which the refresh thread is invoked to fetch data to be refreshed.
assembly-name	Human-understandable name of the deployed cache loader assembly.
class-name	Name of class implementing the ICacheLoader interface.
full-name	Name of assembly to be deployed.
name	Under parameters is the name of the added parameter.
value	Under parameters is the value of the added parameter.
name	Under dataset is the name of the added dataset.
schedule-expression	Refresh schedule expression of the dataset.
schedule-option	Refresh schedule option of the added dataset.

See Also

Cache Startup Loader and Refresher Overview
Implementation of Cache Loader and Refresher
Data Source Providers (Backing Source)
Custom Cache Dependencies