RadarChartOLAPDataModel: Basic Requirements

The main responsibility of a RadarChartOLAPDataModel is to map data members from an OLAP data structure to variable roles in a Radar chart.

In your code, you can explicitly select measures in the OLAP data, or allow the component's OLAP data model to select measures by default.

A Radar chart's primary variable roles are

CategoryVariable

Specifies a classification variable whose values determine the number and arrangement of spokes in the radar chart. A RadarChartOLAPDataModel maps this role to an OLAP column or row level, depending on the OLAP structure.

ResponseVariable

Specifies an analysis variable whose values are represented by the radar spokes. A RadarChartOLAPDataModel maps this role to the first measure in the OLAP structure.

SubgroupVariable

Generates a separate star for each subgroup value. A RadarChartOLAPDataModel uses this role if the OLAP axis that supplies the CategoryVariable role has more than one level and the RadarChart's subgroupEnabled field is true.

To access OLAP data for a graph, you must know the name of the OLAP host server and connect to that server with a valid username and password. To use the OLAP data in a RadarChart, you must

• create an OLAPDataSet, either from the result set of a query that is executed on an OLAP provider or from the metadata that has been mapped to the OLAP data
• assign the OLAPDataSet to a RadarChartOLAPDataModel
• assign the RadarChartOLAPDataModel to a RadarChart.

The following code fragment generates a Radar chart that graphs the causes of failure for different cleaning processes that were used by a manufacturing system.

// Create strings to store an SQL query, the OLAP server name,
// and the connection port.
   String OLAP_QUERY="SELECT "
                   + "{[CAUSE].MEMBERS} ON COLUMNS,"
                   + "{[TIME].[MONTH].MEMBERS} ON ROWS "
                   + "FROM MYOLAPCUBE WHERE ([Measures].[COUNT])"; // specify a valid OLAP data source
   String OLAP_SERVER="myOlapServer.com"; // use a valid server name
   int OLAP_PORT=8800;                    // use a valid port

// Create a RadarChartOLAPDataModel from an OLAPDataSet. The final argument
// on the model constructor sets the chart's subgroupEnabled field to false.
   RadarChartOLAPDataModel olapDataModel = null;
   try {
        // OLAPDataSet arguments: host, port, username, pwd, query
           olapDataModel=new RadarChartOLAPDataModel(
           new OLAPDataSet(OLAP_SERVER, OLAP_PORT, "myUsername", "myPwd",
                           OLAP_QUERY), false);
       } catch (Exception ex) { ex.printStackTrace(); }

// Create a RadarChart that uses the RadarChartOLAPDataModel as its data model
   RadarChart radarChart=new RadarChart();
   radarChart.setDataModel(olapDataModel);