protected void writeToURI(final URI uri, final InputStream stream) throws IOException
{
  final IFile res = (IFile) WorkspaceTools.getResource(uri); //determine the IFile from the given URI
  final int hint = ... //determine correct write hint based on network request and actual resource state

  WorkspaceJob writeJob = new WorkspaceJob("Write content to " + uri)
  {

    public IStatus runInWorkspace(IProgressMonitor monitor)
    {
      try
      {
        if (!res.exists())
          ensureExists(res.getParent());
        switch (hint)
        {
           case CREATE:
             res.create(stream, true, monitor);
             break;
           case APPEND:
             res.appendContents(stream, true, false, monitor);
             break;
           case SET_CONTENT:
             res.setContents(stream, true, true, monitor);
        }
      } catch (CoreException e)
      {
        Close.close(stream);
        return new Status(IStatus.ERROR, "de.d3fact.server.net.interfaces", "Could not write to file " + uri, e);
      }
      return Status.OK_STATUS;
    }
  };

  writeJob.setRule(null);
  writeJob.schedule();
}