Using a global dictionary for fast shared code access

Refer to the Getting ready section of the Using a global dictionary for fast shared data access recipe. Basically, we can just add the code to the same function library and actions.

The first steps of defining the GlobalDictionary variable and the functions to manage its instantiation and disposal are identical, as in the recipe Using a global dictionary for fast shared data access, so we can just skip to the next step.

The remaining implementation deserves special attention. In the Globals.vbs function library that we attached to the test, we will add the following pieces of code:

Class MyOperation1
    Function Run()
        Print typename(me) & " is now running..."
    End Function
End Class

Class MyOperation2
    Function Run()
        Print typename(me) & " is now running..."
    End Function
End Class

Function GetInstance(cls)
    Dim obj
    
    On error resume next
    Execute "set obj = new " & cls
    If err.number <> 0 Then
        reporter.ReportEvent micFail, "GetInstance", "Class " & cls & " is not defined (error #" & err.number & ")"
        Set obj = nothing
    End If
    Set GetInstance = obj
End Function

The two classes follow the command wrapper design pattern. Note that they both contain a Run function (any name would do). This follows a pattern, which enables us to load an instance of each class and store it in our GlobalDictionary variable.

The GetInstance(cls) function acts as a generic constructor for our encapsulated functions. It is absolutely necessary to have such a constructor in the function library because UFT does not support instantiating classes with the operator new within an action. We use the Execute function to make the line of code, resulting from concatenating the command string with the cls parameter passed to the function, and hence, it can return an instance of any class contained in any other associated function library. The function checks if an error occurs while trying to create a new instance of the given class. This could happen if the string naming the class is inaccurate. In such a case, the function returns nothing after reporting a failure to the test report. In such a case, we may wish to halt the test run altogether by using the ExitTest command.

In Action1, we will add the following code:

GlobalDictionary.Add "Op1", GetInstance("MyOperation1")
GlobalDictionary.Add "Op2", GetInstance("MyOperation2")

In Action2, we will add the following code:

GlobalDictionary("Op1").Run
GlobalDictionary("Op2").Run

The output of the test is now as shown in the following screenshot:

When you run this test, the initial process of GlobalDictionary instantiation is executed, as in the previous recipe. Then, we simply add two keys to the GlobalDictionary and assign a reference to each value to an instance of the command wrapper classes MyOperation1 and MyOperation2. When the test flow reaches Action2, we access these instances by retrieving the items (or the values) we stored with the keys, and then have access to the classes' public methods, fields, and properties. The code line is as follows:

GlobalDictionary("Op1").Run

First, it retrieves the reference to the MyOperation1 object, and then, it applies to the Op1 operator to access the public Run method, which just prints the name of the class and a string.

Of course, the Run method of the command wrapper pattern may need a variable number of arguments, because different functions meet different requirements. This can easily be resolved by defining the Run method as accepting one argument and passing a Dictionary object with the keys and values for each variable that is required.

For example, assuming that the dic argument is a dictionary:

Class MyOperation1
    Function Run(dic)
        Print typename(me) & " is now running..."
        Print dic("var1")
        Print dic("var2")
        Print typename(me) & " ended running..."
    End Function
End Class

Now, we would use the following code in Action2 to call the Run method:

Set dic = CreateObject("Scripting.Dictionary")
dic.Add "var1", "Some value"
dic.Add "var2", "Some other value"
GlobalDictionary("Op1").Run

Also refer to the Using a global dictionary for fast shared data access recipe in this chapter. We will also delve more in depth into the command wrapper design pattern in Chapter 7, Using Classes.