@Override public MoreFlowlet add(String name, Flowlet flowlet, int instances) { Preconditions.checkArgument(flowlet != null, UserMessages.getMessage(UserErrors.INVALID_FLOWLET_NULL)); FlowletDefinition flowletDef = new FlowletDefinition(name, flowlet, instances); String flowletName = flowletDef.getFlowletSpec().getName(); Preconditions.checkArgument(instances > 0, String.format(UserMessages.getMessage(UserErrors.INVALID_INSTANCES), flowletName, instances)); Preconditions.checkArgument(!flowlets.containsKey(flowletName), UserMessages.getMessage(UserErrors.INVALID_FLOWLET_EXISTS), flowletName); flowlets.put(flowletName, flowletDef); return this; }