The polling interval property is an optional property for all charts. It specifies the time in milliseconds for the chart’s data to refresh. You can use this for charts that receive any kind of real time data, such as a JSON file that changes periodically. This ensures that the chart is up to date, reflecting the most recent data. This tutorial shows how to configure your portlet’s chart to reflect real time data.
Use the setPollingInterval() method for your chart’s configuration object to
specify the refresh rate. An example view.jsp configuration is shown below:
<%
LineChartConfig _pollingIntervalLineChartConfig = new LineChartConfig();
_pollingIntervalLineChartConfig.put("data", "/foo.json");
_pollingIntervalLineChartConfig.setPollingInterval(2000);
%>
<chart:line
componentId="polling-interval-line-chart"
config="<%= _pollingIntervalLineChartConfig %>"
/>
Figure 1: The polling interval property lets you refresh charts at a given interval to reflect real time data.