[xwiki-devs] [DISCUSSION] XWiki Chart Api & Chart Macro

Hello Devs, I have been examining Dan Miron's patches for http://jira.xwiki.org/jira/browse/XWIKI-3313 & http://jira.xwiki.org/jira/browse/XWIKI-2883 and they are working fine. However I think there are few improvements / refactorings that should be done before comitting the code. Most importantly, I would like us to agree upon the xwiki-chart api and xwiki-chart-macro format. xwiki-chart module ============== In dan's implementation, the chart module is actually called xwiki-jfreechart because it is dependant on the jfreechart api. However I think we can extract a generic chart api from dan's implementation without much of a trouble. In his implementation there are three interfaces: * ChartGenerator * DataSource * DataSourceFactory * PlotFactory Out of these interfaces only PlotFactory is dependant on jfreechart. IMO we can construct a generic chart api by making ChartGenerator & DataSource interfaces component roles, hiding PlotFactory in an internal package and getting rid of DataSourceFactory. So the final API would be something like: interface ChartGenerator { File buildChart(DataSource dataSource, Map<String, Object> parameters, File outputDirectory) throws ChartGeneratorException; } And interface DataSource { // Usual tablemodel like api (from dan's implementation) void init (params) // Initializes this datasource from the parameters passed in, no need of a separate factory. } We can also go to a api / implementation approach with multiple modules as in: /platform/core/trunk/xwiki-chart | |-> xwiki-chart-api | |-> xwiki-chart-jfree But I don't know if this is worth the trouble. xwiki-chart-macro ============= Currently the chart macro has a format like: {{chart chartType="line" source="type:XDOM; table_number:1;range:A1-C3;series:rows" title="line (xy_line_and_shape, default)" width="640" height="480"/}} I think we should change the "chartType" parameter to just "type" and the source parameter would be changed like: source="<id>|<params>" here we will use the <id> part as the component hint for the corresponding DataSource... and the <params> string can be anything specific for that DataSource (so we don't put any restrictions). For an example, we could have a datasource named "xdom" like: source="xdom|document=Main.WebHome;table=someTableId;series=rows;hasHeaderRow=true;hasHeaderColumn=true" We load the DataSource corresponding to "xdom" and let it initialize with the parameters string.... (that's why i put a init() method inside DataSource component role). The rest of the parameters would be standard : title, height, width etc. As a start we will have two types of DataSources: XDom and Inline (Already there). This is a quite big discussion and I don't know If I have explained myself correctly. Please let me know what you think about this and how it can be improved. Thanks a lot. - Asiri