java - JNA vs. DLL (Delphi) -


i'm new(bie) here but, have "big problem"

i have dll (in delphi) , want access java. it's easy if use simple return or procedure in "body" (.dpr) of dll. need use interface because want use same code in desktop application , web application (using java). code bellow:

testlib.dll

library testlib;   {$define testlib}    uses     system.sysutils,     system.classes,     testint in 'testint.pas';    {$r *.res}    function myreturn(test: ptest): pchar; stdcall;   begin       result := 'im here!';       test^.vresult := 'test 123';   end;    exports myreturn;    begin   end.

interface testint.pas

unit testint;    interface    type     ptest = ^ttest;     ttest = record       vresult: pchar;     end;      {$ifndef testelib}     function myreturn(test: ptest): pchar; stdcall;     {$endif}    implementation    {$ifndef testelib}   function myreturn; external 'testlib.dll' name 'myreturn';   {$endif}    end.

and how access using simple application in delphi:

unit formmain;    interface    uses     winapi.windows, winapi.messages, system.sysutils, system.variants, system.classes,   vcl.graphics,     vcl.controls, vcl.forms, vcl.dialogs, vcl.stdctrls;    type     tform1 = class(tform)       button1: tbutton;       procedure button1click(sender: tobject);     private       { private declarations }     public       { public declarations }     end;    var     form1: tform1;    implementation    {$r *.dfm}    uses testint;  //the interface  procedure tform1.button1click(sender: tobject);   var     test: ttest; //type declared in interface testint.pas   begin       showmessage(myreturn(@test)); //returns im here!        showmessage(test.vresult); //test 123   end;    end.

i want access using java (jni, jna, etc... exemple welcome!)

thanks lot guys!

in general delphi dlls (using stdcall calling convention) accessed in same way access win32 apis. should able figure out appropriate type mappings examining sizes of delphi types , replacing them similarly-sized java types.

pchar maps java string, "interface" provided this:

public interface testint extends stdcalllibrary {     testint instance = (testint)native.loadlibrary("testint", testint.class);      class test extends structure {         public string vresult;         public test() { }         public test(pointer p) {              super(p);             read();         }         protected list getfieldorder() { return arrays.aslist(new string[] { "vresult" }); }     }      string myreturn(test test); }

bear in mind david's warning returning strings; if delphi allocates memory, must later free memory, it's easier have caller (java) pass in allocated memory , have delphi write provided buffer.


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