Populate a list of object from a map using stream

Question

I have the below map of and a string

/**
4->"welcome"
3->"to"
2->"my"
1->"blog"
*/

Map<Integer, String> myMap = ImmutableMap.of(4, "welcome", 3, "to", 2, "my",1,"blog");
String s= "welcome to my blog everyone"

Now I need to poulate the below object list by deleting the words from the string based on the order in decending order(the map is already sorted decending)

{
   "level": 1,
   "delete":["welcome"],
   "modString":"to my blog everyone" 
}
{
   "level": 2,
   "delete":["welcome","to"],
   "modString":"my blog everyone" 
}
{
   "level": 3,
   "delete":["welcome","to","my"],
   "modString":"blog everyone" 
}
{
   "level": 4,
   "delete":["welcome","to","my","blog"],
   "modString":"everyone" 
}

The list has the type Delete

public class Delete {
    private Integer level;
    private String modString;
    private List<String> delete;

    public Delete(
            Integer level,
            String modString,
            List<String> delete) {
        this.level = level;
        this.modString = modString;
        this.delete = delete;
    }

 //getters and setters

    }

}

I can do it by iterating the map but I was thinking if this can be done using Streams.

Answer 1

I don't quite get the purpose of the map's keys and their relation to level. But I assume you want a solution to java's variables inside lambdas having to be final. For that purpose you can use java.util.concurrent.atomic.AtomicReference or other classes in the same package.

final AtomicReference<String> modString = new AtomicReference<>(s);
final Comparator<Map.Entry<Integer, String>> comparing = Comparator.comparing(Map.Entry::getKey);
final List<String> deletedOnes = new ArrayList<>(myMap.size());
final List<Delete> result = myMap.entrySet().stream().sorted(comparing.reversed()).map(entry -> {
    deletedOnes.add(entry.getValue());
    modString.set(modString.get().replaceFirst(entry.getValue(), "").trim());
    return new Delete(myMap.size() - entry.getKey() + 1, modString.get(), new ArrayList<>(deletedOnes));
}).collect(Collectors.toList());