Algorithm to detect gaps in C43 files

c43.java

List<DCabeceraC43> headers = getHeadersSorted(toa);
            
DCabeceraC43 first = null;
DCabeceraC43 previous = null;
boolean dateErrors = false;
boolean balanceErrors = false;
            
for (DCabeceraC43 header : headers) {
 
    if (first == null) {
        header.setInitDateErr(false);
        header.setFinalDateErr(false);
        header.setInitBalanceErr(false);
        header.setFinalBalanceErr(false);
        first = header;
    } else {
        long days = DateTools.daysBetween(previous.getFinalDate(), header.getInitialDate());
        header.setInitDateErr(days > 1);
        header.setFinalDateErr(false);
        previous.setFinalDateErr(days > 1);
 
        if (!previous.getSaldoFinal().equals(header.getSaldoInicial())) {
            header.setInitBalanceErr(true);
            previous.setFinalBalanceErr(true);
        } else {
            header.setInitBalanceErr(false);
            header.setFinalDateErr(false);
        }
    }
    dateErrors |= header.isInitDateErr() || header.isFinalDateErr();
    balanceErrors |= header.isInitBalanceErr() || header.isFinalBalanceErr();
    previous = header;
}
      
if (previous != null) {
    toa.setLastC43(previous);
    toa.setC43DateErr(toa.getStartConcil() == null || first.getLoadDate().after(toa.getStartConcil()) || dateErrors);
    toa.setC43BalanceErr(balanceErrors);
 } else {
    toa.setLastC43(null);
    toa.setC43DateErr(false);
    toa.setC43BalanceErr(false);
 }