[Solved] How to pass parameters to a java macro from a Basic one

[Cormic]

Hi,
I have trouble calling a java macro with parameters, i.e. I don't understand what to put in the call of XScript.execute().
In the attached file, I have embedded a java class with two scripts, one with parameters and the other without.
The java code is really simple :

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import com.sun.star.script.provider.XScriptContext;
public class MacroJava {
    public static int getArgsCount(XScriptContext xScriptContext, Object[] args) {
        return args.length;
    }
    public static String getMessage(XScriptContext xScriptContext) {
        return "Appel OK de la macro java";
    }
}

A button in the attached document calls a macro in Basic (module1.testMacroJava) which uses the script manager to call the two java macros.
The call is successful for the java macro getMessage(), but fails for getArgsCount(). Obviously, the script manager cannot match the method signature.
I have tried many configurations for the 3 parameters of the call XScrip.invoke() without success.
I woul be grateful if somebody could give me a clue.

The parcel-descriptor is :

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<?xml version="1.0" encoding="UTF-8"?>
<parcel language="Java" xmlns:parcel="scripting.dtd">
  <script language="Java">
    <locale lang="fr">
      <displayname value="getArgsCount"/>
      <description>
        macro java getArgsCount (avec paramètres)
      </description>
    </locale>
    <functionname value="MacroJava.getArgsCount"/>
    <logicalname value="MacroJava.getArgsCount"/>
    <languagedepprops>
        <prop name="classpath" value="TestMacroJava.jar"/>
    </languagedepprops>
  </script>
  <script language="Java">
    <locale lang="fr">
      <displayname value="getMessage"/>
      <description>
        macro java getMessage (sans paramètres)
      </description>
    </locale>
    <functionname value="MacroJava.getMessage"/>
    <logicalname value="MacroJava.getMessage"/>
    <languagedepprops>
        <prop name="classpath" value="TestMacroJava.jar"/>
    </languagedepprops>
  </script>
</parcel>

I work on Win10 pro , with LibreOffice 24.2.5.2
Sincerely
Cormic

[JeJe]

In your document you're trying to set the aOutParamIndex and aOutParam before the call - leave these, they're filled by the script call not by you. I don't know java but it will depend of whether the parameters are one way (byval in Basic) or two way (byref in Basic)

https://www.openoffice.org/api/docs/com ... cript.html

the call would look like
bar.invoke( {"foo", "foo2", "this-is-ignored" }, aOutParamIndex, aOutParam);
and after the call the out sequences would contain

aOutParamIndex={0,2};
aOutParam={"string from a", "string from c"};

Edit: So try leaving aOutParamIndex, aOutParam as variants.

[Cormic]

Hi JeJe, thanks for you answer.
In Java, parameters are passed by value. But when the parameter is an object, the value is a pointer to the object content, so any modification of the object is seen by the caller.
The initialization of aOutParamIndex and aOutParam in my code is just one of the (very) many configurations I have tried. I have tried letting then uninitialized, and even undeclared (as there is no Option Explicit), whithout any more success.

[JeJe]

OOBasic can't handle pointers.

This says "A String in Java is actually an object"

https://www.w3schools.com/java/java_strings.asp

Have you tried the simplest case - one parameter which is a long instead of a string?

[Cormic]

Basic cannot handle pointers, but the ScriptManager is not written in Basic, but probably in C++ or Java, and its role is also to convert the types. So I don't think the type of the parameters can be a problem. Anyway, I have tried many things, including passing Integers and Longs.

[JeJe]

Here's a simple basic example of calling a basic function, so you at least have the correct calling format.

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sub TestScriptInvoke
dim st as string,script,res
st    = "vnd.sun.star.script:Standard.Module1.test10?language=Basic&location=document"
script =  thiscomponent.getscriptprovider.getScript(st) 
res=script.invoke(array("stringtofirstparam","stringtosecondparam"), aOutParamIndex, aOutParam)
mri aOutParamIndex
mri aOutParam
End Sub

sub test10(byval a,byref b) 
msgbox b
end sub

You could try the LibreOffice forum in case there's someone using Java there who can help with this.

[Cormic]

Hi JeJe, and thanks for the time you spend to help me.
Your (working) example corresponds to what I have understood for the parameters. Unfortunately, it doesn't work in my case.
I have tried :

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    uri    = "vnd.sun.star.script:TestMacroJava.MacroJava.getArgsCount?language=java&location=document"
    script = javaProvider.getScript(uri)
    N = script.invoke(array("stringtofirstparam","stringtosecondparam"), aOutParamIndex, aOutParam)

and I got the same exception.
I have noticed a difference with your exemple. You get the XScript interface directly with

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scriptProvider = thiscomponent.getscriptprovider
script =  scriptprovider.getScript(st)

This master script provider has 5 ChildNodes, among which one is a ScriptProviderForBasic and another a ScriptProviderForJava.
It appears that you can ask directly the master script provider to get a Basic macro, but not a java one, for which you have to ask specifically the ScriptProviderForJava. That seems not logical, but it's what I see. Maybe my problem comes from that difference, but I can't guess why, neither how to get the invoke call working.

[Cormic]

The problem is solved ! It came from an obsolete documentation.
I used the Developer's Guide chapter 28 - Scripting Framework
https://wiki.documentfoundation.org/Doc ... ing_Macros
where it is written in "Handling arguments passed to macros"

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Java: The arguments are passed as an Object[] in the second parameter to the macro method

 public void handleButtonPress( XScriptContext xScriptContext, Object[] args)
 

But that's wrong now, and parameters must be declared explicitely.
With this new definition of the Java macro

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    public static int getArgsCount(XScriptContext xScriptContext, String[] textes, String message) {

using this Basic code

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	Dim textes(2), params(1), outIndex(), outParams() 
	textes(0) =  "valeur 1" : textes(1) = "valeur 2" : textes(2) = "valeur 3"
	params(0) = textes : params(1) = "message"
	uri    = "vnd.sun.star.script:TestMacroJava.MacroJava.getArgsCount?language=java&location=document"
    script = javaProvider.getScript(uri)
    N = script.invoke(params, outIndex, outParams)

it works perfectly.

[Cormic]

I was wrong saying the documentation is obsolete. It is just very incomplete and ambiguous.
Following the documentation, one's declare a Java script by

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public static String maMacro(XScriptContext xScriptContext, Object[] args)

This works only if the array contains at least two different types. For instance :

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Dim param1(2)
param1(0)=thisComponent : param1(1)="un texte" : param1(2) = 12.5
Dim params(0) : params(0) = param1
result = script.invoke(params, outIndex, outParams)

The java script receives args[0] with type "any", args[1] with type String et args[2] with type Double.
But the script will not be called if parameters have the same type.

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param1(0)="un texte": param1(1)="un deuxième texte" : param1(2) = "un troisième texte"]

In that case, the macro must be declared with the right type :

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public static String maMacro(XScriptContext xScriptContext, String[] args)

And the use of an array is not compulsory. One can use a unique parameter, but with the proper type (Object is not possible). For instance :

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public static String maMacro(XScriptContext xScriptContext, Double args)

can be called by :

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Dim D as Double : D = 12.5
Dim params(0) : params(0) = D
result = script.invoke(params, outIndex, outParams)

Passing numeric parametres that way is not really practical, for the ScriptManager doesn't consider the type delared by Dim, but only the real value of the data. That means that, if you change D = 12.5 by D = 12.0, the Script Manager will consider the data as a Byte, and the java macro will be called only if it declares the parameter by 'Byte args' (or 'Short args' or 'Long args' depending of the shortest bit number necessary to code the data). That means that the only secure way to transmit a numerical value is to put it in an array for an Objet[] parameter, and to cope with the different types received.

And last, it is possible to have as many parameters as desired in the Java prototype. For instance

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public static String maMacro(XScriptContext xScriptContext, String[] args1, Object[] args2, String args3, ActionEvent args4)

where all parameters must follow the above rules.