Best way to implement dynamic property access on a static type

[drkstr]

Hello Everyone,

I need to implement a declarative command pattern that can update a value on a variety of static types, given a string value for the key. These types can be modified as needed to support the pattern, but need to be operated on in a generic way (IE. I can make all these types implement a common interface). Each type must react to changes made to these properties.

Here is what I have so far:

public class Main implements EntryPoint{
    @Override
    public void onModuleLoad()
    {
    MyView view = new MyView();


    SetPropertyCommand command = new SetPropertyCommand();
    command.target = view;
    command.property = "text";
    command.value = "Hello World!";


    command.execute();


    RootPanel.get().add(view);
    
    GWT.log("text = " + view.getValue("text"), null);
    }
}


interface IValueTarget
{
    public void setValue(String name, Object value);
    
    public Object getValue(String property);
}


class SetPropertyCommand
{
    public String property;
    
    public IValueTarget target;
    
    public Object value;


    public void execute()
    {
    this.target.setValue(this.property, this.value);
    }
}


class MyView extends Html implements IValueTarget
{
    
    private HashMap<String,Object> _properties = new HashMap<String,Object>();
    
    public void setValue(String name, Object value)
    {
    _properties.put(name, value);
    
    //gross!
    if (name == "text")
        setHtml((String) value);
    }
    
    public Object getValue(String property)
    {
    return _properties.get(property);
    }
}

This seems to work ok, but I really hate the idea idea of switching through a bunch of magic string values in every IValueTarget implementation (there are a lot of them, each with a unique set of properties that can be operated on in this manor).

Is there a way to implement this with strong typing? I was looking at using the new ValueProvider functionality to expose these properties, but then I am still not sure how I would reference them using a String value, and react to changes when a value is set.

Any guidance you can provide will be greatly appreciated.


Thanks for your time!

[drkstr]

Just to clarify a bit, in Actionscript I would do this by putting the logic in getters and setters. This way, all the exposed properties would be included in the API documentation. In Java I could just name my get/set methods to match whatever string value should be used to reference it, and then grab a reference to it using the reflection API. But this doesn't appear to be an option in GWT.

So I guess what my question is, is there any possible way to reference a method using a String, or do I need to implement a function in each of my types that switches through a string value and manually calls the appropriate function?

Thanks again for your time!