Interaction between VBA(Excel) and Java


In the code below, I implemented a one way communication between my Excel AddIn and the Main java application of the World cancer research fund Continuous Update project.

Basically, when a user highlight a cell with a WCRF_CODE (string code attributed to a publication), the button "View In App" is enabled and once clicked, launch the window of the selected publication in the main java application. (If the java application is not found, then it starts a new process).

Here are the steps that lead to functional interprocess communication between a custom excel Ribbon and a java application.

1) An Excel 2010 ribbon with one button with callback that is triggered when  the cell selection change or if the content change in the workbook.
 <?xml version="1.0" encoding="UTF-8"?>  
 <customUI xmlns="http://schemas.microsoft.com/office/2009/07/customui" onLoad="ribbonLoad">  
  <ribbon startFromScratch="false">  
    <tab id="cupTabAddIn" label="CUP">  
       <group id="MyGroup2"  
         label="Java Application">  
           <button id="button_launch" label="See in App" imageMso="MailMergeResultsPreview" onAction="seeWCRF" getEnabled="isWCRFSelected" />  
The callback for the button is "isWCRFselected" if it is true, then the button is enabled. The main action of the button is of course "seeWCRF". I edited the code of the xaml file (my addin) with Custom UI editor.

2) Now that my controls exists there is plenty code to write to make them actually do something useful. First of all I need to catch the events "SheetChange" and "SheetSelectionChange". Since my excel file is an addin I can't just write them down in ThisWorkbook as this is never called. Instead I need to write a class module: "clsApplicationEvents" with the following code.

 Option Explicit  
 Private WithEvents oApp As Excel.Application  
 Property Set XL(Application As Excel.Application)  
 Set oApp = Application  
 End Property  
 Property Get XL() As Excel.Application  
   Set XL = oApp  
 End Property  
 Private Sub oApp_SheetChange(ByVal Sh As Object, ByVal Target As Range)  
 ribbon.ribbon.InvalidateControl "button_launch"  
 End Sub  
 Private Sub oApp_SheetSelectionChange(ByVal Sh As Object, ByVal Target As Range)  
    ribbon.ribbon.InvalidateControl "button_launch"  
 End Sub  

In a normal module called "clsApplicationEventStandard", I wrote

 Option Explicit  
 Global AnyWorkbook As clsApplicationEvents  

And finally I wrote, in ThisWorkbook:
 Option Explicit  
 Private Sub Workbook_Open()  
   Set AnyWorkbook = New clsApplicationEvents  
   Set AnyWorkbook.XL = Excel.Application  
   Debug.Print "Opening"  
 End Sub  

Now we have an addin with buttons, and we can use the workbook event as in non-addins environment. But our button if pressed are not doing anything yet.
 We need to define some more methods...
 Option Explicit  
 ' We keep a reference to the loaded Ribbon  
 Public ribbon As IRibbonUI  
 ' Save a reference to the Ribbon  
 ' This is called from the ribbon's OnLoad event  
 Public Sub ribbonLoad(rb As IRibbonUI)  
   Set ribbon = rb  
 End Sub  
 Public Sub splitribbon(control As IRibbonControl)  
   Call wcrf_buttons.splitup  
 End Sub  
 Public Sub mergeribbon(control As IRibbonControl)  
   Call wcrf_buttons.getConcatenatedList  
 End Sub  
 Public Sub isWCRFSelected(control As IRibbonControl, ByRef enabled)  
   enabled = method_util.isWCRFCode(ActiveCell.Value)  
 End Sub  
 Public Sub seeWCRF(control As IRibbonControl)  
   Call JavaInterprocess.sendApp(ActiveCell.Value)  
 End Sub  

Now, we have methods behind our buttons and these methods of course call other methods (so that I can use these methods without passing by the ribbon as well). The methods behind  splitribbon and mergeribbon are trivials as well as the "isWCRFSelectedMethod" but I will write them down so you can have an idea of what they do.  It is worth to note that  isWCRFSelectedMethod uses regex and so need to have "Microsoft Vb Script Regular Expression 5.5" activated.

''Normally this method is in a module called wcrf_buttons
Sub getConcatenatedList()  
 Dim clipboard As MSForms.DataObject  
 Dim rng As Range  
 Set clipboard = New MSForms.DataObject  
 Dim text$  
 Dim isFirst As Boolean  
 isFirst = True  
 Set rng = Selection.SpecialCells(xlCellTypeVisible)  
 For Each cell In rng  
   If (isFirst) Then  
     text = Trim(cell.Value)  
     isFirst = False  
     text = text & ";" & Trim(cell.Value)  
   End If  
 clipboard.SetText text  
 End Sub

Given a selected range of cells, the method above will concatenate the value in a string with a semi colon as separator. This string will then be placed in the clipboard.

 Sub splitup()  
   Dim arrayOfRs  
   Dim delimitor$  
   Dim output$  
   Dim clipboard As MSForms.DataObject  
   Set clipboard = New MSForms.DataObject  
   delimitor = InputBox("Delimiter please", "Parameter required")  
   arrayOfRs = split(ActiveCell.Value, delimitor)  
   For i = 0 To UBound(arrayOfRs)  
     If (i <> 0) Then  
       output = output & vbCrLf & arrayOfRs(i)  
       output = arrayOfRs(i)  
     End If  
   Next i  
   On Error Resume Next  
   clipboard.SetText output  
 End Sub  

Given a String of item separated by a certain character, this method will split the text in row than can then be paste in Excel.

The method below return true if the format of the text is the one of a WCRF code.
''Normally this method is in a module called method_util
 Public Function isWCRFCode(text As String) As String  
   Dim strPattern As String  
   Dim wcrfCodeList$  
   strPattern = "(LUN|COL|BRE|STM|OES|oes|SKI|NAS|CER|PAN|PRO|LIV)[0-9]{4,7}"  
   Dim regEx As New RegExp  
   Dim strInput As String  
   Dim Myrange As Range  
   Dim matches  
   With regEx  
       .Global = True  
       .MultiLine = True  
       .IgnoreCase = False  
       .Pattern = strPattern  
   End With  
   isWCRFCode = regEx.test(text)  
 End Function  

Now come the big deal, we want to send data to the server (our main java application) For that I created a module called "JavaInterProcess" In the module you can find these methods

 Private Declare Sub Sleep Lib "kernel32" (ByVal dwMilliseconds As Long)  

This is just a small definition of a kernel32 class that when called, will pause the application for dwMilliseconds. It is needed because if our application is not started when we send the command... nothing will happen. So we will use this to wait 10 seconds before the time we launch our application and the time we send the command to the server of our application.

 Public Sub sendApp(wcrfcode As String)  
 Dim ProcID As Integer  
 'Find process of java application  
 'On error StartApp  
 On Error GoTo startApp  
 ProcID = findProcess()  
 GoTo manipulateApp  
   ProcID = startApp()  
 ' Activate the Java Application application.  
 On Error GoTo erreurmsg:  
 AppActivate (ProcID)  
 'send Command via server  
 Call serverSocket.sendMsg("", 8084, "JAVACUP:" & wcrfcode)  
 Exit Sub  
 MsgBox ("unexpected error occured!")  
 End Sub  

This is the main method of our interprocess communication, it first see if our java application process is running by calling the method "findProcess()". If a process is there, it is fine we can activate the window of our  current java process then call the method serverSocket.sendMsg(add, port, msg). Conversely if the application is not running then, we start the java application, wait 10 seconds and send the command.

 Private Function findProcess() As Integer  
 Dim oShell As Object  
 Set oShell = CreateObject("WScript.Shell")  
 Dim oExec As Object  
 Dim oOutput As Object  
 Set oExec = oShell.Exec("jps")  
 Set oOutput = oExec.StdOut  
 Dim s As String  
 Dim sLine As String  
 While Not oOutput.AtEndOfStream  
   sLine = oOutput.ReadLine  
   'in debug ApplicationEntryPoint  
   If (InStr(1, sLine, "Program")) Then  
     s = Replace(sLine, "Program", "")  
     s = Replace(s, " ", "")  
   End If  
 On Error GoTo erreur:  
   findProcess = CInt(s)  
   Exit Function  
   findProcess = CVErr(xlErrValue)  
 End Function 

The method findProcess above return  a PID of the process or an errer xlErrValue if there is no process running.

Below is the code to start our application.

 Private Function startApp() As Integer  
 Dim pid%  
 pid = Shell("java -jar ""C:\Program Files (x86)\wcrfapp\wcrfapp.jar"" ", vbHide)  
 Sleep (10000)  
 startApp = pid  
 End Function  

I found the code of a server in VBA on this forum. So I will just copy paste it here as a reference:
 Public Const AF_INET = 2  
 Public Const SOCK_STREAM = 1  
 Public Const SOCKET_ERROR = 1  
 Public Const FD_SETSIZE = 64  
 Public Const FIONBIO = 2147772030#  
 Public Const SOCKADDR_IN_SIZE = 16  
 Public Type WSADATA  
   wVersion As Integer  
   wHighVersion As Integer  
   szDescription As String * 257  
   szSystemStatus As String * 129  
   iMaxSockets As Integer  
   iMaxUdpDg As Integer  
   lpVendorInfo As Long  
 End Type  
 Public Type SOCKADDR_IN  
   sin_family As Integer  
   sin_port As Integer  
   sin_addr As Long  
   sin_zero As String * 8  
 End Type  
 Public Type fd_set  
   fd_count As Long  
   fd_array(FD_SETSIZE) As Long  
 End Type  
 Public Type timeval  
   tv_sec As Long  
   tv_usec As Long  
 End Type  
 Public Declare Function WSAStartup Lib "wsock32.dll" (ByVal intVersionRequested As Integer, lpWSAData As WSADATA) As Long  
 Public Declare Function WSACleanup Lib "wsock32.dll" () As Long  
 Public Declare Function w_socket Lib "wsock32.dll" Alias "socket" (ByVal lngAf As Long, ByVal lngType As Long, ByVal lngProtocol As Long) As Long  
 Public Declare Function w_closesocket Lib "wsock32.dll" Alias "closesocket" (ByVal SocketHandle As Long) As Long  
 Public Declare Function w_bind Lib "wsock32.dll" Alias "bind" (ByVal socket As Long, Name As SOCKADDR_IN, ByVal namelen As Long) As Long  
 Public Declare Function w_connect Lib "wsock32.dll" Alias "connect" (ByVal socket As Long, Name As SOCKADDR_IN, ByVal namelen As Long) As Long  
 Public Declare Function w_send Lib "wsock32.dll" Alias "send" (ByVal socket As Long, buf As Any, ByVal length As Long, ByVal flags As Long) As Long  
 Public Declare Function w_recv Lib "wsock32.dll" Alias "recv" (ByVal socket As Long, buf As Any, ByVal length As Long, ByVal flags As Long) As Long  
 Public Declare Function w_select Lib "wsock32.dll" Alias "select" (ByVal nfds As Long, readfds As fd_set, writefds As fd_set, exceptfds As fd_set, timeout As timeval) As Long  
 Public Declare Function htons Lib "wsock32.dll" (ByVal hostshort As Integer) As Integer  
 Public Declare Function ntohl Lib "wsock32.dll" (ByVal netlong As Long) As Long  
 Public Declare Function inet_addr Lib "wsock32.dll" (ByVal Address As String) As Long  
 Public Declare Function ioctlsocket Lib "wsock32.dll" (ByVal socket As Long, ByVal cmd As Long, argp As Long) As Long  
 Public Declare Function FormatMessage Lib "kernel32" Alias "FormatMessageA" (ByVal dwFlags As Long, lpSource As Any, ByVal dwMessageId As Long, ByVal dwLanguageId As Long, ByVal lpBuffer As String, ByVal nSize As Long, Arguments As Long) As Long  
 Private Sub CloseSocket(socket As Long)  
   If socket <> -1 Then  
     w_closesocket socket  
   End If  
 End Sub  
 Public Function sendMsg(Address As String, port As Integer, URI As String)  
   Dim ret As Long  
   Dim SocketHandle As Long  
   Dim wd As WSADATA  
   Dim localAddress As SOCKADDR_IN  
   Dim serverAddress As SOCKADDR_IN  
   Dim URIRequest As String  
   Dim retBuff(1024) As Byte  
   Dim retString As String  
   Dim tempString As String  
   VcitajURI = ""  
   SocketHandle = -1  
   ret = WSAStartup(&H101, wd)  
   If ret <> 0 Then GoTo ErrorHandler  
   SocketHandle = w_socket(AF_INET, SOCK_STREAM, 0)  
   If SocketHandle = -1 Then GoTo ErrorHandler  
   localAddress.sin_family = AF_INET  
   localAddress.sin_port = 0  
   localAddress.sin_addr = 0  
   ret = w_bind(SocketHandle, localAddress, SOCKADDR_IN_SIZE)  
   If ret = -1 Then GoTo ErrorHandler  
   serverAddress.sin_family = AF_INET  
   serverAddress.sin_port = htons(port)  
   serverAddress.sin_addr = inet_addr(Address)  
   ret = w_connect(SocketHandle, serverAddress, SOCKADDR_IN_SIZE)  
   If ret = -1 Then GoTo ErrorHandler  
   URIRequest = URI & vbCrLf  
   ret = w_send(SocketHandle, ByVal URIRequest, Len(URIRequest), 0)  
   If ret = -1 Then GoTo ErrorHandler  
   CloseSocket SocketHandle  
 End Function  

We now have a functioning client that will send data to our application. Now we need to program the application so that it understand the command (WCRF code) send by the client.

This is the start of our application.

  public static void main(String[] args) {  
      * Listener, if any key is sent from Excel the code of the key will be  
      * */  
     Thread server=new Thread(new Listener());  

All the code of the server is centralised in the class "Listener below":

 package GUI.InterProcessCommunication;  
 import BO.Incidence.IncidenceMain_BO;  
 import GUI.Incidence.IncidenceSearch_Launcher;  
 import GUI.SplashScreen.SplashScreen_DataLoading;  
 import java.awt.*;  
 import java.awt.event.KeyEvent;  
 import java.io.BufferedReader;  
 import java.io.IOException;  
 import java.io.InputStreamReader;  
 import java.io.PrintWriter;  
 import java.net.InetSocketAddress;  
 import java.net.ServerSocket;  
 import java.net.Socket;  
 import java.nio.ByteBuffer;  
 import java.nio.channels.ServerSocketChannel;  
 import java.nio.channels.SocketChannel;  
 import java.util.ArrayList;  
 import java.util.Optional;  
  * Created by casteven on 11/10/2016.  
 public class Listener implements Runnable {  
   int port = 8084;  
   public void run() {  
     int portNumber = 8084;  
     try {  
       ServerSocket socket = new ServerSocket(portNumber);  
       while (true) {  
         Socket clientSocket = socket.accept();  
         BufferedReader in = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));  
         // Initiate conversation with client  
         String inputLine = "";  
         while ((inputLine = in.readLine()) != null) {  
           if (inputLine.startsWith("JAVACUP:")) {  
             String wcrf = inputLine.replaceAll("JAVACUP:", "");  
             Optional<IncidenceMain_BO> publicationFromExcel = BL.Incidence.IncidenceMain_BL.selectAll_Studies_per_WCRF(wcrf).stream().findAny();  
             if (publicationFromExcel.isPresent()) {  
               Runnable r = new IncidenceSearch_Launcher(SplashScreen_DataLoading.Instance(), publicationFromExcel.get());  
               Thread t = new Thread(r);  
     }catch(IOException e){  

As you can see it is an infinite loop in a thread that accepts connections and in case that the received WCRF_Code exists, launch the window with right publication data.

This is how to ribbon looks like for those interested:

Now the idea is to extend this communications with more objects and methods! Yeeepie yeah