How do I tell a controller which component is calling it?

Question

I have a number of components that all share the same controller but have slightly different layouts.

Everything's working great but for part of it to work in trying to find a way to tell the controller which component it is that's calling it?

If it were a regular page i would just use ApexPages.currentPage().getUrl(). But I can't seem to find a way to of anything similar with a component?

I even tried to just create a parameter like this in the component

<apex:attribute name="page"  description="This is the page." type="String" assignTo="{!pageName}"/>

where i would pass the page name along with the controller call, like so

 <c:PrintBankFees page="PrintBankFees" />

but that doesnt seem to work either?

in my controller i have (simplified greatly to focus on the issue in question)

public String pageName {get;set;}
public String instructions {get;set;}

public PrintController() {
        instructions = pageName;
}

and my component is setup like

<apex:component controller="PrintController">

     <apex:attribute name="page"  description="This is the page." type="String" assignTo="{!pageName}"/>
     <apex:outputText escape="false" Value="{!instructions}" />

</apex:component>

but instructions is always blank?

Answer 1

I think (hard to tell since you've simplified the controller) but this is due to you trying to use the value inside of the constructor of the controller.

The setters for controller members are not called until after the constructor has run. A pattern I typically use is make sure that all getter methods make sure initialisation code has been run like so (simplified example):

public String pageName {get;set;}
public String instructions {set;}
private Boolean initialised = false;

public PrintController() {
    // don't use values from parameters here, they won't be set!
}

private void Init() {
    if(initialised)
        return;

    instructions = pageName;
    initialised = true;
}

public GetInstructions() {
    Init();

    return instructions;
}