try {
pf = this.layoutMasterSet.getLayoutMaster(pageMasterFirst).getPageMaster();
pe = this.layoutMasterSet.getLayoutMaster(pageMasterEven).getPageMaster();
po = this.layoutMasterSet.getLayoutMaster(pageMasterOdd).getPageMaster();
this.pageMasterFactory = new AlternatingPageMasterFactory(pf,pe,po);
} catch (java.lang.NullPointerException e) {
throw new FOPException("at least one of the page-master names in"
+ " sequence-specifier-alternating is not in"
+ " layout-master-set");
}