scripting-function

Scripting Function Example

Overview

Provides a basic example of a scripting function which executes through a remote procedure call (RPC). In a client scope, the function delegates to the module's RPC handler, which then calls multiply on the gateway and returns the result.

Implementation

scripting-function-common defines the interface and abstract class that all the implementing functions must adhere to, regardless of scope.

The ClientScriptModule class creates the actual RPC handler, using the API's ModuleRPCFactory.create() method. An instance of ClientScriptModule is used in the Designer and Client scope to provide details about the function. When actually executed, the ModuleRPCFactory will automatically call the GatewayHook's getRPCHandler method, which returns the GatewayScriptModule with the actual implementation of MathBlackBox.

The ModuleRPCFactory handles the "heavy lifting" of passing values back and forth between scopes.

Adding to the Example

The initial example demonstrates the steps involved with adding a new system function into Ignition with the module SDK, but let's take the example a bit further by adding a new function.

This section assumes you are able to successfully build a module from the initial example already. If you're having any trouble, head back to the Getting Started section at the root of these examples.

Adding a Function

In the initial example, the multiply() function is defined under the AbstractScriptModule class (located under scripting-function-common). Let's add a simple function:

public String helloWorld(){
        return "Hi there!";
}

That's it! We're ready to test it out! Build the module, install it, launcher the designer, open the Script Console and try calling the function:

print system.example.helloWorld()

Adding Descriptions

If you examine at the contents of the autocomplete descriptions (Ctrl+Space bar) you'll notice that our function does not have any descriptions. Obviously we haven't added any yet, so let's look at how to do that.

The Programmer's Guide contains the full details on all of the Module SDK's Annotations. In short, we can use the @ScriptFunction annotation to denote where the descriptions for our function should be. We can add the annotation to our hellowWorld() function:

@ScriptFunction(docBundlePrefix = "AbstractScriptModule")
public String helloWorld(){
    return "Hi there!";
}

In this case, the "docBundlePrefix" argument is stating that the AbstractScriptModule properties file (also located under scripting-functions-common) has the descriptions that should be used in conjunction with this function.

Next we need to actually write the descriptions. Open the AbstractScriptModule.properties file. You'll see the descriptions for the multiply() function. The notation here is somewhat obvious but in the interest of clarity:

• desc is the description of the function
• param.%argName% is the description for a particular argument
• returns is the description for the return value

Our function does not accept any arguments, so we only have two entries to add to helloWorld():

helloWorld.desc=Returns a friendly greeting
helloWorld.returns=The string "Hi There!"

Build the module, install the new module on top of the old, relaunch the designer, and check the autocomplete popup. You should see your new descriptions.