Hello I try using Google Chart to display the trendlines, based on some datas generated from the Java files. Here is part of my codes
public void resolveEvolution() {
this.evolution = new ArrayList<Long>();
this.evolutionTime = new ArrayList<String>();
Calendar first = Calendar.getInstance();
first.setTime(this.start);
first.set(Calendar.DAY_OF_MONTH, 1);
Calendar last = Calendar.getInstance();
last.setTime(this.end);
int i = 0;
this.dt = DataTable.create();
dt.addColumn(ColumnType.NUMBER, "Time");
dt.addColumn(ColumnType.NUMBER, "Utilisation");
dt.addRow();
while (first.before(last)) {
Calendar endMonth = Calendar.getInstance();
endMonth.setTime(first.getTime());
endMonth.add(Calendar.MONTH, 1);
endMonth.add(Calendar.DAY_OF_MONTH, -1);
this.evolution
.add(actionQueries.countByComponent(this.selectedComponent,
first.getTime(), endMonth.getTime()));
this.evolutionTime.add(first.get(Calendar.MONTH) + "/"
+ first.get(Calendar.YEAR));
dt.addRow();
dt.setValue(i, 0, i);
dt.setValue(i, 1,
actionQueries.countByComponent(this.selectedComponent,
first.getTime(), endMonth.getTime()));
i++;
first.add(Calendar.MONTH, 1);
}
}
public DataTable getDt() {
System.out.println(this.dt);
return this.dt;
}
Here is my xhtml:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml"
xmlns:h="http://java.sun.com/jsf/html"
xmlns:f="http://java.sun.com/jsf/core">
<head>
<script type="text/javascript" src="https://www.google.com/jsapi"></script>
<script type="text/javascript">
google.load("visualization", "1", {packages:["corechart"]});
google.setOnLoadCallback(drawChart);
function drawChart() {
var data = new google.visualization.DataTable();
data = "#{globalComponentsManager.dt}";
var options = {
title: 'Test',
trendlines: { 0: {} }
};
var chart = new google.visualization.ScatterChart(document.getElementById('chart_div'));
chart.draw(data, options);
}
</script>
</head>
<body>
<div id="chart_div" style="width: 900px; height: 500px;"></div>
</body>
</html>
Obviously, it doesn't work. So how can I pass the datatable from java to JavaScript ? I am using the JSF frame. Thanks.
Well, I found the solution at last. And I hope it could help the people who will meet the same difficulty in the future. JSF could pass some parameters from Java to Web Page, including the JavaScript within a JSF page. So I use a StringBuilder in Java file for building the string of Rows, like [[1,2],[5,9],[4,3]]. and then I pass this String to JavaScript, the codes of google chart, like data.addRows(#{stastics.rows}). For the other parts of google chart codes, just refer the google chart documentations. It worked well and I got the chart I needed finally.