I have below data structure like this
Country,StateID1 where StateID1 contains "City1","City2","City3" etc
Country,StateID2 where StateID2 contains "City1","City2","City3" etc
I know i can't use HashMap to implement above data structure because if i add StateID2 to same Country StateID1 will be replace with StateID2 for eg
map.put("1","1111");
map.put("1","2222");
output
key:value
1:2222`
i am facing hard time to figure out how to do this. I need some support from you guys
You need some wrapping object for storing your 'state' data. Then you can have a structure like this: Map<String, List<StateBean>>. This way you can handle a list of state for every country.
If data are just Strings use Map<String, List<String>>
You can have a Map<String, Set<String>>.
Store the StationIDs in an ArrayList object and add those object in a HashMap using key-value pair .. where key is the Country against the StationId ArrayList Object.
StateID1 = ["City1","City2"] // ArrayList
StateID2 = ["City1","City2"]
We could have the map as Country,ListOfStates
ListOfStates could be a list that contains StateIds
Or StateIds as a Map with StateId as key and list of cities as value
You could create a class for the same.
class YourClass
{
String country;
State state;
}
class State
{
Set<String> cities;
}
You can then use this class as a data structure. You don't really need to use Collections framework for the same.
OR
If you really want to do it using Collections, then you can use a combination of Country and StateId as the key, and the list of cities as the value in a Map. For ex:
String country = "1";
String state = "1";
String separator = "-" // You could use any separator
String key = country + separator + state;
Set<String> cities = new HashSet<String>();
cities.add("1");
cities.add("2");
Map<String, Set<String>> map = new HashMap<>();
map.put(key, cities);
So your key would be 1-1 and value would be 12.
Use can Data Structure map < String,vector < String >> , map < class T,vector < class U > >
