Iterate Map of String and List of integer with not fixed values-CodePudding

I have a Map of String and List counts.I want to iterate this and want to set map values in an object.

    counts.put("ABC", Arrays.asList(1,2,3));
    counts.put("XYZ", Arrays.asList(1,2));
    counts.put("PQR", Arrays.asList(1));
    counts.put("IJK", Arrays.asList());

map values are of list type and it can be 1,2,3 etc. or empty but will not exceed 3 in short size can not be more than 2.

I have written code like below:

for (Map.Entry<String,List<Integer>> count : counts.entrySet()) {
        InventoryOwnerManagerResult result = new InventoryOwnerManagerResult();
        InventoryOwnerPresence  presence = new InventoryOwnerPresence();
        switch (count.getValue().size()) {
            case 1:
                presence.setConfigCount(count.getValue().get(0));
                presence.setWebsitesCount(0);
                presence.setSourcesCount(0);
                break;
            case 2:
                presence.setConfigCount(count.getValue().get(0));
                presence.setWebsitesCount(count.getValue().get(1));
                presence.setSourcesCount(0);
                break;
            case 3:
                presence.setConfigCount(count.getValue().get(0));
                presence.setWebsitesCount(count.getValue().get(1));
                presence.setSourcesCount(count.getValue().get(2));
                break;
            default:
                presence.setConfigCount(0);
                presence.setWebsitesCount(0);
                presence.setSourcesCount(0);
                break;
        }
         result.setInventoryOwnerPresence(presence);
    }

This is very old school as well as not an appropriate approach.

Is there any other way to do this?

CodePudding user response：

You can replace the switch with the following:

List<Integer> counts = count.getValue();
presence.setConfigCount(counts.size() > 0 ? counts.get(0) : 0);
presence.setWebsiteCount(counts.size() > 1 ? counts.get(1) : 0);
presence.setSourcesCount(counts.size() > 2 ? counts.get(2) : 0);

This will behave differently if numbers has more than 3 elements; this solution discards only the 4th and later elements, your solution discards all. That doesn't matter though, since you'll never get more than 3 elements.

Which option you chose is personal preference. The switch is clear but verbose, the ternary expressions are concise but may be a bit harder to read for some. As far as performance goes, the switch probably performs better but I doubt you'll really see the difference.