Hi, I'm currently working with flink for my bachelor thesis and I'm running into some odd issues with flink in regards to factories.
I've built a small "proof of concept" and the code can be found here: https://gitlab.tubit.tu-berlin.de/gehaxelt/flink-factorytest The idea is that a Config-singleton holds information or objects to use, e.g. an AppleFactory (default) which implements a specific IDataFactory interface. This AppleFactory is then used in a flatMap to create Apples (objects which implement the IData interface): > > System.out.println("Factory before processedData: " + > Config.getInstance().getFactory().getClass()); > DataSet<IData> processedData = > this.getEnv().fromCollection(inputData).flatMap(new FlatMapFunction<Integer, > IData>() { > @Override > public void flatMap(Integer integer, Collector<IData> collector) > throws Exception { > if (integer % 2 == 0) { > > collector.collect(Config.getInstance().getFactory().newInstance()); > } > } > }); > System.out.println("Factory after processedData: " + > Config.getInstance().getFactory().getClass()); > try { > System.out.println("Class created: " + > processedData.collect().get(0).getClass()); > this.getDataHolder().setDataList(processedData.collect()); > } catch (Exception e) { > e.printStackTrace(); > } This happens in the "Config -> initData()" function. My Flink-Job looks like this: > public static void main(String[] args) throws Exception { > > Config c = Config.getInstance(); //Use AppleFactory by default > > //BOOM: Somehow flink ignores this? > c.setFactory(new PearFactory()); > > c.initData(); > > DataSet<IData> data = > c.getEnv().fromCollection(c.getDataHolder().getDataList()); As you can see before the "c.initData()" call I set the factory to a "PearFactory()" which will produce Pear-objects (also implementing the IData interface). Running the code will print the following text: > Class created: class factorytest.Data.Apple This, however, means that flink didn't catch (or ignored?) that the factory has changed and still creates objects of type Apple. Instead I'd expect the processedData.collect() list to contain Pear-objects. What is even more confusing is that the two "Factory before/after processedData" print statements correctly return the PearFactory class. What's the best way to fix this? Any tips/tricks/questions? I guess that this issue is might be hard to explain in words, so I'd really appreciate it if someone could have a look at the code and maybe do an example run: Job.java: https://gitlab.tubit.tu-berlin.de/gehaxelt/flink-factorytest/blob/master/src/main/java/factorytest/Job.java Config.java: https://gitlab.tubit.tu-berlin.de/gehaxelt/flink-factorytest/blob/master/src/main/java/factorytest/Config.java Example run: https://gitlab.tubit.tu-berlin.de/gehaxelt/flink-factorytest/blob/master/EXAMPLE_RUN_OUTPUT.txt Kind regards, Sebastian Neef
