Plugins

There are several kind of plugins:

• org.apache.sirona.gauges.Gauge and org.apache.sirona.gauges.GaugeFactory: you can add your own gauges
• org.apache.sirona.reporting.web.plugin.api.Plugin: add feature to the web GUI

Write your own gauge

To add your own Gauge you have two main solutions:

• simply implement a org.apache.sirona.gauges.Gauge and register it using ServiceLoader mecanism (META-INF/services/org.apache.sirona.gauges.Gauge)
• implement a org.apache.sirona.gauges.GaugeFactory which is registered it using ServiceLoader mecanism (META-INF/services/org.apache.sirona.gauges.GaugeFactory) and return the gauges you want to register

What is GaugeFactory designed for? Imagine a custom gauge is parameterized. You’ll surely want to register it several times with different parameters. If you use Gauge SPI you’ll need to do N implementations (which makes the parameters useless). With GaugeFactory you just need to return the built instances:

public class MyGaugeFactory implements GaugeFactory {
    @Override
    public Gauge[] gauges() {
        return new Gauge[] { new MyGauge(1); new MyGauge(2); };
    }
}

Extend the reporting GUI

To extend the reporting GUI just write your own org.apache.sirona.reporting.web.plugin.api.Plugin. Here too it relies on java ServiceLoader (SPI) mecanism.

Here is the Plugin interface:

public interface Plugin {
    String name();
    Class<?> endpoints();
    String mapping();
}

A plugin has basically a name (what will identify it in the webapp and in the GUI - it will be the name of the plugin tab), a mapping, ie which base subcontext it will use for its own pages (for instance /jmx, /myplugin …) and a class representing endpoints.

To make it more concrete we’ll use a sample (the standard Hello World).

public class HelloPlugin implements Plugin {
    public String name() {
        return "Hello";
    }

    public Class<?> endpoints() {
        return HelloEndpoints.class;
    }

    public String mapping() {
        return "/hello";
    }
}

public class HelloEndpoints {
    @Regex // will match "/hello"
    public Template home() {
        return new Template("hello/home.vm", new MapBuilder<String, Object>().set("name", "world).build());
    }

    @Regex("/world/([0-9]*)/([0-9]*)") // will match "/hello/world/1/2"
    public String jsonWorld(final long start, final long end) {
        return "{ \"name\": \world\", \"start\":\"" + long1 + "\",\"end\":\"" + long2 + "\"}";
    }
}

<h1>Hello</h1>
<div>
    Welcome to $name
</div>

@Regex("/resources/myresource.css")
public void filterCss(final TemplateHelper helper) {
    helper.renderPlain("/resources/myresource.css");
}