Plugin discovery

[ashleypursglove]

Hi all,

I've been looking around on the net for a tutorial on how to create a plugin discovery system for a java program.

I am trying to follow the example found at What is Java Reflection? | JAVA Developer's Journal

I have a simple class which implements my plugin interface.

public class Main implements IXactPlugin
{
    String name = "Plugin1";

    public static void main(String[] args)
    {
        System.out.println("Here");
        Main moo = new Main();
    }

    public Main()
    {
        process();
        System.out.println(getName());
        System.out.println(methods()[0].getName());
    }
    public void process()
    {
        System.out.println("Process");
    }

    public String getName()
    {
        return name;
    }

    public Method[] methods()
    {
        Method m[] = null;
        try
        {

            Class c = Class.forName(this.getClass().getName());
            m = c.getDeclaredMethods();
        }
        catch (Throwable e)
        {
           System.err.println(e);
        }
        return m;

    }
}

I then want to load that plugin and be able to call those methods having dynamically loaded that class in another program.

Here is the code I have for the plugin loader

File folder = new File("C:/Users/Ash/Documents/NetBeansProjects/PluginFramework/plugins");
        File[] listOfFiles = folder.listFiles();
        
        for ( int i = 0; i < plugInNames.length; i++ ) 
        {
            MyApplicationPlugIn plugIn = (MyApplicationPlugIn)Class.classFor( plugInNames[i] );
        }

Problem I am having is the line

MyApplicationPlugIn plugIn = (MyApplicationPlugIn)Class.classFor( plugInNames[i] );

It cant find the classFor method.

Any help would be greatly appreciated.

Kind Regards

Ash

[JosAH]

Problem I am having is the line

MyApplicationPlugIn plugIn = (MyApplicationPlugIn)Class.classFor( plugInNames[i] );

It cant find the classFor method.

The name of that (static) method is Class.forName(String className). It loads the class for you (if not already loaded) but throws an Exception if it can't find the class. Read the API documentation for the Class class.

kind regards,

Jos

[ashleypursglove]

Thanks for the reply Jos.

I thought this might be the case.

I've changed the line as follows

IXactPlugin plugIn = (IXactPlugin)Class.forName( "Main" );

But now get the compilation error

inconvertible types
required: pluginframework.IXactPlugin
found: java.lang.Class<capture#2 of ?>

Kind Regards

Ash