Communicating with parent component

Question 1

Your component is available to you within your page as a variable where you can access the variables required from within your page like so:

@Component(id = "myComponent")
private MyComponent myComponent;

@SetupRender //or any other render event method
private void setup() {
    Object compVariable = myComponent.getYourVariable();
}

More elegant if you ask me is to use event bubbling as it makes it easer to refactor some logic out to a deeper component if needed.

Component:

@Inject
private ComponentResources resources;

@SetupRender //or any other lifecycle event method
private void triggerEvent() {
    Object yourVariable = new Object();
    resources.triggerEvent("YOUR_EVENT_NAME", new Object[]{yourVariable}, null);
    //add an event callback if needed where I use null here
}

Page:

@OnEvent(value = "YOUR_EVENT_NAME")
private void handleComponentEvent(Object yourVariable) {
    //do something with yourVariable
    //even return something which would then can be handled by your component callback handler
}

Question 2

You can use usual tapestry parameter.

<t:mycomponent value="myValue"/>

If this value will be changed on the component side, it will be available on the container side and vice versa.

Question 3

I've used all three of these approaches, depending on context. I generally prefer event bubbling, where that makes sense.