mondrian.spi
Interface DataSourceChangeListener

All Known Implementing Classes:

DataSourceChangeListenerImpl, DataSourceChangeListenerImpl2, DataSourceChangeListenerImpl3, DataSourceChangeListenerImpl4

public interface DataSourceChangeListener

Definition of a data source change listener. A change listener can be specified in the connection string. It is used to ask what is changed in the datasource (e.g. database). Everytime mondrian has to decide whether it will use data from cache, it will call the change listener. When the change listener tells mondrian the datasource has changed for a dimension, cube, ... then mondrian will flush the cache and read from database again. It is specified in the connection string, like this :

Jdbc=jdbc:odbc:MondrianFoodMart; JdbcUser=ziggy; JdbcPassword=stardust; DataSourceChangeListener=com.acme.MyChangeListener;

This class should be called in mondrian before any data is read, so even before cache is build. This way, the plugin is able to register the first timestamp mondrian tries to read the datasource.

Since:

Dec 12, 2006

Author:

Bart Pappyn

Method Summary

boolean	isAggregationChanged(Aggregation aggregation) Checks if the given aggregation has changed since the previous time this function was called.
boolean	isHierarchyChanged(RolapHierarchy hierarchy) Checks if the given hierarchy has changed since the previous time this function was called.

Method Detail

isHierarchyChanged

boolean isHierarchyChanged(RolapHierarchy hierarchy)

Checks if the given hierarchy has changed since the previous time this function was called. The first time, this function will be called when the cache is still empty. This is because the plugin is able to register the first timestamp the function was accessed. It is highly recommended to optimize the plugin and minimize the time needed to evaluate this function, because this plugin is called many times for each mondrian query.

isAggregationChanged

boolean isAggregationChanged(Aggregation aggregation)

Checks if the given aggregation has changed since the previous time this function was called. The first time, this function will be called when the cache is still empty. This is because the plugin is able to register the first timestamp the function was accessed.