Create a Gauge Using Java

Overview

FusionCharts is a JavaScript charting library that enables you to create interactive charts, gauges, maps and dashboards in JavaScript. We have built a simple server-side Java (JSP) wrapper for FusionCharts. The FusionCharts server-side JSP wrapper lets you easily add rich and interactive gauges to any JSP project. Using the wrapper, you can create gauges in your browsers, without writing any JavaScript code.

In this page, we'll see how to install FusionCharts and render a gauge using the FusionCharts server-side JSP wrapper.

Installation

In this section, we will show you how to install FusionCharts Suite XT and the FusionCharts JSP wrapper and all the other dependencies on your system.

The FusionCharts JSP wrapper requires JAVA 6 or higher.

• Copy and paste the fusioncharts.java file from integrations > java > fusioncharts-wrapper in your project folder.

• Include the FusionCharts JavaScript files, which can be downloaded from here.

• Include the FusionCharts theme file to apply the style to the widgets.

// Include FusionCharts core file
<script type="text/javascript" src="https://cdn.fusioncharts.com/fusioncharts/latest/fusioncharts.js"></script>

// Include FusionCharts Theme file
<script type="text/javascript" src="https://cdn.fusioncharts.com/fusioncharts/latest/themes/fusioncharts.theme.fusion.js"></script>
COPY

// Include FusionCharts core file
<script type="text/javascript" src="path/to/local/fusioncharts.js"></script>

// Include FusionCharts Theme file
<script type="text/javascript" src="path/to/local/themes/fusioncharts.theme.fusion.js"></script>
COPY

That completes the installation of FusionCharts and the jsp-fusioncharts component.

Create Your First Gauge

Gauges are powerful tools that can showcase information using a radial or linear scale to display data.

To start with, we'll build a simple angular gauge showcasing Nordstrom's Customer Satisfaction Score as shown below.

FusionCharts Suite has 95+ chart types for you to explore. Find the complete list of chart types here.

The angular gauge is shown below:

Chart data

The thresholds for the above sample is shown in the table below:

So, any score less than 50 is bad and is red. Any score between 50 and 75 is average and is yellow. Any score above 75 means good and are green.

FusionCharts accepts data in JSON format. Following code is the JSON representation of the above table with the required attributes to render the above chart.

{
  // Chart Configuration
  "chart": {
    "caption": "Nordstrom's Customer Satisfaction Score for 2017",
    "lowerLimit": "0",
    "upperLimit": "100",
    "showValue": "1",
    "numberSuffix": "%",
    "theme": "fusion",
    "showToolTip": "0"
  },
  // Chart Data
  "colorRange": {
    "color": [
      {
        "minValue": "0",
        "maxValue": "50",
        "code": "#F2726F"
      },
      {
        "minValue": "50",
        "maxValue": "75",
        "code": "#FFC533"
      },
      {
        "minValue": "75",
        "maxValue": "100",
        "code": "#62B58F"
      }
    ]
  },
  "dials": {
    "dial": [
      {
        "value": "81"
      }
    ]
  }
}COPY

In the above JSON:

• Create the chart object to define the elements of the gauge.

• Create the colorRange object to set the color associated with the specific range of values.

• Specify minValue and maxValue within the color array under the colorRange object.

• Set the code attribute to specify the hex color of respective ranges.

• Create the dials object to represent the customer satisfaction score.

• Create the dial object under dials object to set the value of customer satisfaction score.

The chart object and the respective arrays contain a set of key-value pairs known as attributes. These attributes are used to set the functional and cosmetic properties of the gauge.

Now that you have the data in JSON format, let's see how to render the chart.

Render the Chart

To render the chart, follow the steps below:

• Include the FusionCharts JSP wrapper in your project.

• Include the fusioncharts library.

• Include the FusionCharts theme file to apply the style to the charts.

• Store label-value pairs in an object.

• Set the JSON data as the data source for the chart.

• Store the chart configurations in an object.

• Convert the final chart configuration to JSON string.

• Create the chart instance and set the following:

  • Set the chart type as angulargauge. Each gauge is represented with a unique alias. For Angular Gauge, the alias is angulargauge. Find the complete list of gauges with their respective alias here.

  • Set the gauge id.

  • Set the width and height (in pixels).

  • Set the container for the gauge.

  • Set the dataFormat as JSON.

  • Embed the json data as the value of the dataSource.

• Finally, use a container using <div> to render the gauge.

The consolidated code is shown below:

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
        <title>Insert title here</title>
        <script src="path/to/local/fusioncharts.js"></script>
        <script src="path/to/local/themes/fusioncharts.theme.fusion.js"></script>
    </head>
    <body>
        <div id="gauge"></div>
        <%
            //store chart config name-config value pair
            Map<String, String> chartConfig = new HashMap<String, String>();
            chartConfig.put("caption", "Nordstrom's Customer Satisfaction Score for 2017");
            chartConfig.put("lowerLimit", "0");
            chartConfig.put("upperLimit", "100");
            chartConfig.put("showValue", "1");
            chartConfig.put("numberSuffix", "%");
            chartConfig.put("theme", "fusion");
            chartConfig.put("showToolTip", "0");
            //store dial value config
            Map<String,String> dial = new HashMap<String,String>();
            dial.put("value","81");
            //store color range-color
            ArrayList<ColorRange> color = new ArrayList<ColorRange>();
            color.add(new ColorRange(0,50,"#F2726F"));
            color.add(new ColorRange(50,75,"#FFC533"));
            color.add(new ColorRange(75,100,"#62B58F"));

            //json data to use as chart data source
            StringBuilder jsonData = new StringBuilder();
            //build chart config object
            jsonData.append("{'chart':{");
            for(Map.Entry conf:chartConfig.entrySet())
            {
                jsonData.append("'" + conf.getKey()+"':'"+conf.getValue() + "',");
            }
            jsonData.replace(jsonData.length() - 1, jsonData.length() ,"},");

            StringBuilder range = new StringBuilder();
            //build colorRange object
            range.append("'colorRange':{");
            range.append("'color':[");
            for(int i =0; i< color.size(); i++)
            {
                range.append("{'minValue':'" + color.get(i).min + "','maxValue':'" + color.get(i).max + "','code':'" + color.get(i).colorCode +"'},");
            }
            range.replace(range.length() - 1, range.length(),"]},");
            //build dials object
            StringBuilder dials = new StringBuilder();
            dials.append("'dials':{");
            dials.append("'dial':[");
            for(Map.Entry dialCnf:dial.entrySet())
            {
                dials.append("{'" + dialCnf.getKey() + "':'" + dialCnf.getValue() +"'},");
            }
            dials.replace(dials.length() - 1, dials.length(),"]}");

            jsonData.append(range.toString());
            jsonData.append(dials.toString());
            jsonData.append("}");

            //Create gauge instance
            // gaugetype, gaugeID, width, height,container id, data format, data
            FusionCharts gauge = new FusionCharts(
                "angularGauge",
                "first_gauge",
                "400",
                "350",
                "gauge",
                "json",
                jsonData.toString()
            );
        %>
        <%= gauge.render() %>
    </body>
</html>
COPY

That's it! Your first gauge using the FusionCharts JSP wrapper is ready.

Problem Rendering the Chart?

In case there is an error, and you are unable to see the chart, check for the following:

• If you are getting a JavaScript error on your page, check your browser console for the exact error and fix accordingly. If you're unable to solve it, click <> to get in touch with our support team.

• If the chart does not show up at all, but there are no JavaScript errors, check if the FusionCharts Suite XT JavaScript library has loaded correctly. You can use developer tools within your browser to see if fusioncharts.js was loaded.

• If you get a Loading Data or Error in loading data message, check whether your JSON data structure is correct, or there are conflicts related to quotation marks in your code.