Real-Time Chart with Snapshot

[JSP Version] jspdemo/realtimesnapshot.jsp
<%@page import="ChartDirector.*, java.util.*" %>
<%
//
// Data to draw the chart. In this demo, the data buffer will be filled by a random data generator.
// In real life, the data is probably stored in a buffer (eg. a database table, a text file, or some
// global memory) and updated by other means.
//

// We use a data buffer to emulate the last 240 samples.
int sampleSize = 240;
double[] dataSeries1 = new double[sampleSize];
double[] dataSeries2 = new double[sampleSize];
double[] dataSeries3 = new double[sampleSize];
Date[] timeStamps = new Date[sampleSize];

// Our pseudo random number generator
double firstDate = new Date().getTime() / 1000 - timeStamps.length;
for(int i = 0; i < timeStamps.length; ++i) {
    double p = firstDate + i;
    timeStamps[i] = new Date((long)p * 1000);
    dataSeries1[i] = Math.cos(p * 2.1) * 10 + 1 / (Math.cos(p) * Math.cos(p) + 0.01) + 20;
    dataSeries2[i] = 100 * Math.sin(p / 27.7) * Math.sin(p / 10.1) + 150;
    dataSeries3[i] = 100 * Math.cos(p / 6.7) * Math.cos(p / 11.9) + 150;
}

// Create an XYChart object 600 x 320 pixels in size
XYChart c = new XYChart(600, 320);

// Set the plotarea at (55, 60) and of size 520 x 235 pixels with transparent background and border.
// Enable both horizontal and vertical grids by setting their colors to grey (cccccc). Set clipping
// mode to clip the data lines to the plot area.
c.setPlotArea(55, 60, 520, 235, -1, -1, Chart.Transparent, 0xcccccc, 0xcccccc);
c.setClipping();

// Add a title to the chart using dark grey (0x333333) 20pt Arial Bold font
c.addTitle("Real-Time Chart with Snapshot", "Arial Bold", 20, 0x333333);

// Add a legend box at the top of the plot area using horizontal layout. Use 10pt Arial Bold font,
// transparent background and border, and line style legend icon.
LegendBox b = c.addLegend(55, 30, false, "Arial Bold", 10);
b.setBackground(Chart.Transparent, Chart.Transparent);
b.setLineStyleKey();

// Set the x and y axis stems to transparent and the label font to 10pt Arial
c.xAxis().setColors(Chart.Transparent);
c.yAxis().setColors(Chart.Transparent);
c.xAxis().setLabelStyle("Arial", 10);
c.yAxis().setLabelStyle("Arial", 10);

// Add y-axis title using 12pt Arial font
c.yAxis().setTitle("Y-Axis Title Placeholder", "Arial", 12);

// For the automatic x and y axis labels, set the minimum spacing to 75 and 30 pixels.
c.xAxis().setTickDensity(75);
c.yAxis().setTickDensity(30);

// Set the x-axis label format
c.xAxis().setLabelFormat("{value|hh:nn:ss}");

// Create a line layer to plot the lines
LineLayer layer = c.addLineLayer2();

// The x-coordinates are the timeStamps.
layer.setXData(timeStamps);

// The 3 data series are used to draw 3 lines. Here we put the latest data values as part of the
// data set name, so you can see them updated in the legend box.
layer.addDataSet(dataSeries1, 0xff0000, c.formatValue(dataSeries1[dataSeries1.length - 1],
    "Alpha: {value|2}"));
layer.addDataSet(dataSeries2, 0x00cc00, c.formatValue(dataSeries2[dataSeries2.length - 1],
    "Beta: {value|2}"));
layer.addDataSet(dataSeries3, 0x0000ff, c.formatValue(dataSeries3[dataSeries3.length - 1],
    "Gamma: {value|2}"));

// Create the WebChartViewer to output the chart
WebChartViewer viewer = new WebChartViewer(request, "chart1");

// Check if is a download request
String downloadFormat = request.getParameter("download");
if ((downloadFormat != null) && (downloadFormat != "")) {
    out.clear();

    // Download filename
    String filename = "demo_" + c.formatValue(timeStamps[timeStamps.length - 1], "yyyymmddhhnnss");

    if (downloadFormat.equals("pdf")) {
        // Output in PDF
        viewer.setChart(c, Chart.PDF);
        viewer.streamChart(response, filename + ".pdf");
    } else {
        // Output in PNG
        viewer.setChart(c, Chart.PNG);
        viewer.streamChart(response, filename + ".png");
    }
    return;
}

// Output the chart
viewer.setChart(c, Chart.SVG);

// Check if is a streaming request
if (viewer.isStreamRequest()) {
    out.clear();
    viewer.streamChart(response);
    return;
}
%>
<!DOCTYPE html>
<html>
<head>
    <title>Real-Time Chart with Snapshot</title>
    <script type="text/javascript" src="cdjcv.js"></script>
</head>
<body style="margin:0px">
<table cellspacing="0" cellpadding="0" style="border:black 1px solid;">
    <tr>
        <td align="right" colspan="2" style="background:#000088; color:#ffff00; padding:0px 4px 2px 0px;">
            <a style="color:#FFFF00; font:italic bold 10pt Arial; text-decoration:none" href="http://www.advsofteng.com/">
                Advanced Software Engineering
            </a>
        </td>
    </tr>
    <tr valign="top">
        <td style="width:130px; background:#c0c0ff; border-right:black 1px solid; border-bottom:black 1px solid;">
            <br />
            <br />
            <div style="font:12px Verdana; padding:10px;">
                <b>Update Period</b><br />
                <select id="UpdatePeriod" style="width:110px">
                    <option value="5">5</option>
                    <option value="10" selected="selected">10</option>
                    <option value="20">20</option>
                    <option value="30">30</option>
                    <option value="60">60</option>
                </select>
                <br /><br /><br />
                <b>Time Remaining</b><br />
                <div style="width:108px; border:#888888 1px inset;">
                    <div style="margin:3px" id="TimeRemaining">0</div>
                </div>
            </div>
            <br />
            <br />
            <br />
            <br />
            <div style="text-align:center">
                <input type="button" value="Download PDF" style="width:112px; font:10pt Arial"
                    onclick="JsChartViewer.get('<%=viewer.getId()%>').partialUpdateAsAttachment('download=pdf');" /><br/>
                <input type="button" value="Download PNG" style="width:112px; font:10pt Arial; margin-top:8px;"
                    onclick="JsChartViewer.get('<%=viewer.getId()%>').partialUpdateAsAttachment('download=png');" />
            </div>
        </td>
        <td style="border-left:black 1px solid; padding:5px 0px 0px 5px;" >
            <!-- ****** Here is the chart image ****** -->
            <%=viewer.renderHTML(response)%>
        </td>
    </tr>
</table>
<script type="text/javascript">

//
// Executes once every second to update the countdown display. Updates the chart when the countdown reaches 0.
//
function timerTick()
{
    // Get the update period and the time left
    var updatePeriod = parseInt(document.getElementById("UpdatePeriod").value);
    var timeLeft = Math.min(parseInt(document.getElementById("TimeRemaining").innerHTML), updatePeriod) - 1;

    if (timeLeft == 0)
        // Can update the chart now
        JsChartViewer.get('<%=viewer.getId()%>').streamUpdate();
    else if (timeLeft < 0)
        // Reset the update period
        timeLeft += updatePeriod;

    // Update the countdown display
    document.getElementById("TimeRemaining").innerHTML = timeLeft;
}
window.setInterval("timerTick()", 1000);

</script>
</body>
</html>