is it possible to have multiple values for a single key in the java dictionary class??
You should take a look at the MultiMap class from the apache commons collections
You can use a regular Map
and have the values be Collection
s:
Map<Integer, List<String>> map = new HashMap<Integer, List<String>>();
map.put(0, Arrays.asList("foo", "bar"));
map.put(1, new ArrayList<String>());
map.get(1).add("blag");
Or you can use MultiMap
from the Apache Commons Collections.
A
MultiMap
is aMap
with slightly different semantics. Putting a value into the map will add the value to aCollection
at that key. Getting a value will return aCollection
, holding all the values put to that key.For example:
MultiMap mhm = new MultiHashMap(); mhm.put(key, "A"); mhm.put(key, "B"); mhm.put(key, "C"); Collection coll = (Collection) mhm.get(key);
coll
will be a collection containing "A", "B", "C".
(Unfortunately, MultiMap
does not use generics.)
First, regarding the dictionary class: That class is considered obselete, the documentation recommends using Map instead.
This kind of collection you are seeking is called a multimap. You could implement one yourself with a list, but that is tedious.
You may want to use a MultiMap from either Apache Collections or from the Google Collections. While I am personally a fan of the apache collections, they do not really support generics, so a Google multimap may be safer.