But why would I need that?

As you can see from the above examples, you can implement Java functionality to your LotusScript code. This can be good if your Java programming skills aren’t that great or you already have some code in LotusScript and you wish to add functionality. For me, it would do fine in cases where I converted documents in a database to PDF on user request, or when I needed an agent to login user to notes via web in the background, or as I mentioned, when I needed to implement some functionality from other department in my already existing code. Instead, I re-wrote several agents into Java, which in the end didn’t prove to be that bad of a decision, but about that some other day.

But how do I do that?

There is a functionality called LS2J that does exactly that for you. If you will, you can imagine it as an adaptor for LotusScript that allows you to call Java classes. I will give you a small example. It is based on my user login class, although, there is really no code there to log in the user.

First you need to create/obtain a java library that does what you want. I named that library jclass:UserLogin.

public class CUserLogin {
   String m_strUsername;
   String m_strPassword;

   public void Initialize(String strUsername, String strPassword) {
      if ((strUsername.length() == 0) ||
          (strPassword.length() == 0))
         return;

      m_strUsername = strUsername;
      m_strPassword = strPassword;
   }

   public boolean run() {
      // add code that will perform auto-login
      return true;
   }
}

Then, I strongly suggest you create a LotusScript library, containing a class that will do actual Java to LotusScript conversion. Why? So you have to do it only once.
My script library called class:UserLogin is depicted below.

Uselsx "*javacon"
Use "jclass:UserLogin"

Class CUserLogin
	loginObj As JavaObject

	Sub New (strUsername As String, strPassword As String)
		Dim js As New JAVASESSION
		Dim loginClass As JAVACLASS

		Set loginClass = js.GetClass ("CUserLogin")
		Set loginObj = loginClass.CreateObject ()

		Call loginObj.Initialize (strUsername, strPassword)
	End Sub

	Function run() As Boolean
		run = loginObj.run()
	End Function
End Class

And that is it. Now all you have to do, is use this script library in your code. Where you need it. I created a simple agent that will pop-up a window with text depicting login success.

Use "class:UserLogin"

Sub Initialize
	Dim userLogin As CUserLogin

	Set userLogin = New CUserLogin ("test", "test123")
	If (userLogin.run()) Then
		Messagebox "Login succeeded"
	Else
		Messagebox "Login failed!"
	End If
End Sub

The Adapter pattern converts the interface of a class into an interface the client expects. Adapter lets classes work together even if they couldn’t otherwise due to incompatible interfaces.

So how does this work in practice?

You will mostly need adapters when you will obtain code from someone else. But just for the sake of simplicity, we will look into unlikely scenario, when you will get a code that prints “Hello World!” and write an adaptor that displays “Hello adapters!” in message box using the same interface.

First you need a client class and it’s interface. As we know, interfaces are not implemented in LotusScript. Thus, an abstract class will be used instead. Then we’ll need a client class. Both are pasted below:

Class CHelloWorldInterface
	Sub printText ()
	End Sub
End Class

Class CHelloWorld As CHelloWorldInterface
	Sub printText ()
		Print "Hello World!"
	End Sub
End Class

Now, we need to create our interface that displays “Hello adapters!” in message box.

Class CHelloAdaptersInterface
	Sub msgboxText ()
	End Sub
End Class

Class CHelloAdapters As CHelloAdaptersInterface
	Sub msgboxText ()
		Messagebox "Hello Adapters!"
	End Sub
End Class

All we need now is an adapter.

Class CHelloAdpatersAdapter As CHelloWorldInterface
	m_helloAdapter As CHelloAdaptersInterface

	Sub new (helloAdapter As CHelloAdaptersInterface)
		Set Me.m_helloAdapter = helloAdapter
	End Sub

	Sub printText()
		Call m_helloAdapter.msgboxText()
	End Sub
End Class

And to bind it together, here is an agent that will output both results.

Sub Initialize
	Dim hw As CHelloWorld
	Dim ha As CHelloAdapters
	Dim haa As CHelloWorldInterface

	Set hw = New CHelloWorld ()
	Set ha = New CHelloAdapters ()
	Set haa = New CHelloAdaptersAdapter (ha)

	'test HelloAdapters
	Call ha.msgboxText()

	'test HelloWorld
	Call testHello (hw)

	'test HelloAdaptersAdapter
	Call testHello (haa)
End Sub

Sub testHello (hello As CHelloWorldInterface)
	Call hello.printText()
End Sub