Allow Symlinks in Subdirectory

Inside of this:
private FilePath getSourceDirectory(FilePath basePath) throws IOException, InterruptedException {
String subdirectory = StringUtils.trimToEmpty(this.subdirectory);
if (!subdirectory.isEmpty() && !subdirectory.startsWith("/")) {
subdirectory = "/" + subdirectory;
}
FilePath sourcePath = basePath.withSuffix(subdirectory).absolutize();
if (!sourcePath.isDirectory() || !isSubDirectory(basePath, sourcePath)) {
throw new IllegalArgumentException("Provided path (resolved as '" + sourcePath
+"') is not a subdirectory of the workspace (resolved as '" + basePath + "')");
}
return sourcePath;
}

Can we get another clause that will allow for symlinks to also not throw the illegal argument?