@Override protected void execute() { String find = ""; // Default empty string Packet pfind = findport.receive(); if (pfind != null) { find = (String) pfind.getContent(); drop(pfind); } findport.close(); String repl = " "; // Default empty string Packet prepl = replport.receive(); if (prepl != null) { repl = (String) prepl.getContent(); drop(prepl); } replport.close(); Packet pin; while ((pin = inport.receive()) != null) { String out = ""; String in = (String) pin.getContent(); out = in.replaceAll(find, repl); drop(pin); Packet pout = create(out); outport.send(pout); } }