how to make a list to be used in given methods

Question

I have an Arraylist which has a Map in it. I want to convert the list with respect to a key and value pair and store it into an another List.

I have a list which gives output as:

List<Map<String, String>> mainList = new ArrayList<Map<String, String>>();

{Date=29/01/2018, Type=UNI, Number=17131176}
{Date=29/01/2019, Type=UPS, Number=17592158}
{Date=29/01/2020, Type=CP2, Number=17601558}
{Date=27/01/2015, Type=CP3, Number=17457472}
{Date=27/01/2015, Type=MBY, Number=17112367}
{Date=21/01/2015, Type=CP4, Number=17843672}

How can I make this list to be used in these two methods?

public void excludeNumbers(List<String> Numbers, Date Date)
public void excludeTypes(List<String> Types, Date Date)

Answer 1

Try this.

   excludeNumbers(mainList.stream()
        .map(m -> m.get("Number"))
        .collect(Collectors.toList()), date);
    excludeTypes( mainList.stream()
        .map(m -> m.get("Type"))
        .collect(Collectors.toList()), date);