Dynamic Child Components

[Former Member]

I'm trying to write a parent component that manages a number of child components dynamically at runtime, which all implement a component interface.

I can't find any decent examples on this subject as most seem to skim over the details or assume a concrete dependendancy on a named child component.

The code I am using is as follows but I dont think it is correct:

componentUsage1 = wdThis.wdGetMaxTestPluginComponentUsage();

componentUsage2 = wdThis.wdGetMaxTestPluginComponentUsage();

if(componentUsage1.hasActiveComponent()) {

componentUsage1.deleteComponent();

}

componentUsage1.createComponent("com.x.MaxTestExpensesComp",".com/tms_maxtestexpenses");

if(componentUsage2.hasActiveComponent()) {

componentUsage2.deleteComponent();

}

componentUsage2.createComponent("com.x.MaxTestProcurementComp","x.com/tms_maxtestprocure");

wdThis.wdGetMaxTestPluginInterface().initialiseComponent();

I have 2 child components that implement the same component interface. In this example I could just implement a direct relationship from the parent to the 2 child components but I want to pass the component names and dc names at runtime and dynamically load n components.

The parent component has a usage relationship defined to the MaxTestPlugin component interface.

1 - In the example above I am creating 2 component usages. Is this the correct way of creating the components? Can I create two component usages from the relationship wdThis.wdGetMaxTestPluginComponentUsage() at the same time or does the second overwrite the first?

2 - Assuming I can have 2 component usages at the same time, how do I then invoke a method on one of the child components specifically?

I would expect to be able to do something like this: componentUsage1.executePlugin(employeeElement.getEmployeeNumber(),GlobalConstants.INIT_TRIPNO);

I tried to do this by the following code:

IExternalIMaxTestPlugin interfaceController1 = (IExternalIMaxTestPlugin) componentUsage1.getInterfaceController();

interfaceController1.executePlugin(employeeElement.getEmployeeNumber(),GlobalConstants.INIT_TRIPNO);

but this doesn't invoke the method on the child component or do anything at all apart from return without erroring.

The only way I have seen in the examples is to use the usage relationship name:

wdThis.wdGetMaxTestPluginInterface().executePlugin(employeeElement.getEmployeeNumber(),GlobalConstants.INIT_TRIPNO);

But which of the two child components is this calling the method on? To me it doesnt make sense, but it seems to call the method on both.

3 - So does this mean that I can only use one of the child components if they both implement the same component interface and the parent has a usage relationship to the interface rather than to both the child components directly?

Surely I must be missing something? Hopefully someone can help me out? Otherwise the whole concept of loosely coupled components in WebDynpro seems rather inadequate.

Cheers,

Steve

[Former Member]

Incase anyone else has encountered this problem, the following lines do actually work correctly. I'm not sure why they didnt initially:

IExternalIMaxTestPlugin interfaceController1 = (IExternalIMaxTestPlugin) componentUsage1.getInterfaceController();

interfaceController1.executePlugin(employeeElement.getEmployeeNumber(),GlobalConstants.INIT_TRIPNO);