/*
     * main method to try them out
     */
    public static void main(String[] args) {
        List<ProcessAnimal> animals = new ArrayList<ProcessAnimal>();
        List<ProcessAnimal> excluded = new ArrayList<ProcessAnimal>();
        
        for (int i = 0; i < 40; i++) {
            ProcessAnimal animal = new ProcessAnimal();
            animal.setInternalId(i);
            animals.add(animal);
        }

        for (int i = 0; i < 10; i++) {
            ProcessAnimal animal = new ProcessAnimal();
            animal.setInternalId(i++);
            i++;
            excluded.add(animal);
        }

        long start = System.currentTimeMillis();
        for (int i = 0; i < 20000; i++) {
            List<ProcessAnimal> incl = testLists1(animals, excluded);
//            System.out.println("Incl.size " + incl.size());
        }
        System.out.println("Time spent1: " + (System.currentTimeMillis() - start));
        
        
        start = System.currentTimeMillis();
        for (int i = 0; i < 20000; i++) {
            List<ProcessAnimal> incl = testLists2(animals, excluded);
//            System.out.println("Incl.size " + incl.size());
        }
        System.out.println("Time spent2: " + (System.currentTimeMillis() - start));        
        
    }
    
    /**
     * This one is faster when the excluded list is big
     */
    private static List<ProcessAnimal> testLists2(List<ProcessAnimal> animals, List<ProcessAnimal> excluded) {
        List<ProcessAnimal> result = new ArrayList<ProcessAnimal>();
        HashMap<Integer, ProcessAnimal> animalMap = new HashMap<Integer, ProcessAnimal>();
        HashMap<Integer, ProcessAnimal> exclMap = new HashMap<Integer, ProcessAnimal>();
        for (ProcessAnimal animal : animals) {
            animalMap.put(animal.getInternalId(), animal);
        }
        for (ProcessAnimal animal : excluded) {
            exclMap.put(animal.getInternalId(), animal);
        }

        Set<Integer> keys = animalMap.keySet();

        for (Integer key : keys) {
            if(exclMap.get(key) == null) {
                result.add(animalMap.get(key));
            }
        }
        
        return result;
    }
    
    /**
     * This one is faster when the excluded list is small
     */
    private static List<ProcessAnimal> testLists1(List<ProcessAnimal> animals, List<ProcessAnimal> excluded) {
        List<ProcessAnimal> result = new ArrayList<ProcessAnimal>();
        for (ProcessAnimal animal : animals) {
            boolean included = true;
            for (ProcessAnimal excludedAnimal: excluded) {
                if(animal.getInternalId() == excludedAnimal.getInternalId()) {
                    included = false;
                }
            }
            if(included) {
                result.add(animal);
            }
        }
        return result;
    }