if (ph.getLsn() > -1 && requiresRedo(loggable, page)) {
if (ph.getLsn() != Page.NO_PAGE && requiresRedo(loggable, page)) {
    protected void redoUpdateHeader(UpdateHeaderLoggable loggable) {        DOMPage page = getCurrentPage(loggable.pageNum);        DOMFilePageHeader ph = page.getPageHeader();        if (ph.getLsn() > -1 && requiresRedo(loggable, page)) {            if (loggable.nextPage != Page.NO_PAGE)                ph.setNextDataPage(loggable.nextPage);            if (loggable.prevPage != Page.NO_PAGE)                ph.setPrevDataPage(loggable.prevPage);            page.setDirty(true);            ph.setLsn(loggable.getLsn());            dataCache.add(page, 2);        }    }