Invoking method on a Java class from lotus script (LS2J)

Question

Most dignified developers,

I'm having trouble invoking a method on my own java class from a lotus script agent.

My Java class simplified looks like this

import lotus.domino.*;

public class MyClass{
   /* .. omitted constructor and other methods .. */

   public void myMethod(Document doc){
      /* ... do things with the document object ...*/
   }

}

Now this class is included with the proper use statement, and I can iterate over the classmethods on the class object in lotus script to get the signature of the arguments needed.

But when I try to invoke the method I get a LS2J: Parameter mismatch calling Method myMethod

I've tried both with dot notation on the JavaObject (No I'm not using a Mac ;)) and ADT

Dim doc as NotesDocument
Dim jSession As JavaSession
Dim jClass As JavaClass
Dim jObject As JavaObject

...

Set jSession = New JavaSession()
Set jClass = jSession.Getclass("MyClass")

Set jObject = jClass.Createobject()
Call jObject.myMethod(doc)

and respectively

Dim jMethod as JavaMethod
...

Set jMethod = jClass.Getmethod("myMethod", "(Llotus/domino/Document;)V")
tmp = jMethod.Invoke(jObject,doc)

Also I've added error handling (OnError ..) to print out the results of any JavaError (+ stacktrace) but they end up empty so no further clues there.

I'm using Designer version 9.0

Any ideas/pointers/gotchas? It's driving me bald.

Answer 1

You are using the correct approach to calling your Java method but you can not pass Notes backend objects as parameters.

You can parse a string with the document universal id, for instance, and then in your Java method look up the document using the universal id.

Alternatively, migrate your Lotusscript logic to Java :-)

Answer 2

Maybe you don't need CreateObject..

This is how I do it:

Dim jSession As New JavaSession()
Dim jClass As JavaClass()
Set jClass = jSession.GetClass("MyClass")

If jClass.myMethod(doc) Then

Full example added

Java class:
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.URL;

public class GetFileFromUrl {

    public static boolean getFileFromUrl(String imageUrl, String filePath) {
        try {
            URL url = new URL(imageUrl);
            InputStream is = url.openStream();
            OutputStream os = new FileOutputStream(filePath);
            byte[] b = new byte[2048];
            int length;
            while ((length = is.read(b)) != -1) {
                os.write(b, 0, length);
            }
            is.close();
            os.close();
            return true;
        } catch (Exception e) {
            e.printStackTrace();
            return false;
        }
    }
}

LotusScript:

UseLSX "*javacon"  
Use "GetFileFromUrl"

Private Function GetFileFromUrl(url As String, outputPath As String) As Boolean
    Dim jSession As New JavaSession
    Dim jClass As JavaClass
    Set jClass = jSession.GetClass("GetFileFromUrl")
    If jClass.getFileFromUrl(url, outputPath) Then
        GetFileFromUrl = True
    End If
End Function