Our application administers companies, for each of which a logo can be uploaded. The logo can also be saved (downloaded) for promotional purposes.

There are buttons for up- and downloads, respectively, that can be activated/deactivated depending on user rights.

The following is an example of client and server actions, starting with the client implementation for the upload:

/**
 * Selects the company logo with a file chooser.
 * 
 * @throws Throwable if an error occurs while file choosing
 */
public void doUploadLogo() throws Throwable
{
    getApplication().getLauncher().getFileHandle(this, 
                                                 "uploadLogo", "Choose company logo");
}
 
/**
 * Sends the company logo to the server.
 * 
 * @param pFileHandle the company logo
 * @throws Throwable if a communication error occurs
 */
public void uploadLogo(IFileHandle pFileHandle) throws Throwable
{
    getConnection().callAction("uploadLogo", 
                               rdbCompany.getValue("CPNY_ID"), 
                               pFileHandle);
}

Client implementation for the download:

/**
 * Downloads the company logo and opens a save dialog.
 * 
 * @throws Throwable if a communication error occurs
 */
public void doDownloadLogo() throws Throwable
{
    IFileHandle fileHandle = (IFileHandle)getConnection().callAction("downloadLogo",
                                                    rdbCompany.getValue("CPNY_ID"));
 
    if (fileHandle != null)
    {
        getApplication().getLauncher().saveFileHandle(fileHandle);
    }
}

Server implementation for the upload:

/**
 * Stores the company logo.
 * 
 * @param pCpnyId the company id
 * @param pLogo the company file handle
 * @throws Exception if an error occurs during store
 */
public void uploadLogo(BigDecimal pCpnyId, IFileHandle pLogo) throws Exception
{
    CallableStatement statement = null;
 
    try
    {
        //database mode
        statement = getDataSource().getConnection().prepareCall(...);
        statement.setBigDecimal(1, pCpnyId);
        statement.setString(2, pFileHandle.getFileName());
        statement.setBinaryStream(3, 
                                  new BufferedInputStream(pFileHandle.getInputStream()), 
                                  (int)pFileHandle.getLength());
        statement.execute();
    }
    finally 
    {
       try
       {
            statement.close();
       }
       catch (Throwable pThrowable)
       {
           // Do nothing!   
       }
    }
}

Server implementation for the download:

/**
 * Sends the company logo to the client.
 * 
 * @param pCpnyId the company id from which we want the logo
 * @return the company file handle or <code>null</code> if the company is not available
 * @throws Exception if an error occurs when accessing the company
 */
public RemoteFileHandle downloadFile(BigDecimal pCpnyId) throws Exception
{
   CallableStatement statement = null;
 
   try
   {
      statement = getDataSource().getConnection().prepareCall(...);
      statement.setBigDecimal(1, pScjaId);
      statement.registerOutParameter(2, Types.VARCHAR);
      statement.registerOutParameter(3, Types.BLOB);
 
      statement.execute();
 
      String fileName = statement.getString(2);
      if (fileName == null)
      {
         return null;
      }
      else
      {
         return new RemoteFileHandle(fileName, statement.getBlob(3).getBinaryStream());
      }
   }
   finally 
   {
      try
      {
          statement.close();
      }
      catch (Throwable pThrowable)
      {
          // Do nothing!   
      }
   }
}