ca.uhn.cache
Interface IUnstationaryDataSource

All Superinterfaces:

IDataSource

public interface IUnstationaryDataSource

extends IDataSource

An extension of IDataSource that allows unstationary data. We call data "unstationary" if it might move from one semantic region to another over time. (In other words, if an IQuery might return a certain data item at one time but not return the same item at another time because its values have changed.) If any item in a set of source data might be unstationary in any dimension, you must use this interface to provide access to it. If not, you should use IDataSource. This interface is used as follows:

1. Client queries cache.
2. Cache finds remainder query and uses IDataSource.execute(IQuery[]) to get missing semantic regions
3. Cache uses IUnstationaryDataSource.execute(IQuery[], Date) to get updates for regions that are already in the cache (the cache time is used as the second paramter)
4. Combined cache results and remainder results returned to client.

Version:

$Revision: 1.1 $ updated on $Date: 2005/01/24 22:52:08 $ by $Author: bryan_tripp $

Author:

Bryan Tripp

Method Summary

IQueryResult

execute(IQuery[] theQueries, java.util.Date theUpdatedSinceTime) Runs one or more queries against the data source.

Methods inherited from interface ca.uhn.cache.IDataSource

execute

Method Detail

execute

public IQueryResult execute(IQuery[] theQueries,
                            java.util.Date theUpdatedSinceTime)
                     throws DataSourceException

Runs one or more queries against the data source.

Parameters:

theQueries - queries to run

theUpdatedSinceTime - only data that have been updated since this time should be returned

Returns:

data matching the given queries (may return before all data are available)

Throws:

DataSourceException - If the execute operation could not be successfully completed.