Java Generics: Useing multiple generic types in one collection type
I would like to use two generic types as a key for a hash map. Effectively:
Map<CollectionType<Integer, Integer>, Character> map = new HashMap<>();
I am trying to find if this is possible, and if so which collection type I could use. The right type needs to be able to accept duplicate values. i.e. <1, 0>, <1, 1>, <2, 0> could all be used as a key in the map
for additional background the key in the map will be coordinates on a hex grid, and the value is what is currently stored at that location.
java generics collections
edited Nov 21 '18 at 4:21
Nicholas K
6,89761133
asked Nov 20 '18 at 3:39
jwmorsejwmorse
133
add a comment |
I would like to use two generic types as a key for a hash map. Effectively:
Map<CollectionType<Integer, Integer>, Character> map = new HashMap<>();
I am trying to find if this is possible, and if so which collection type I could use. The right type needs to be able to accept duplicate values. i.e. <1, 0>, <1, 1>, <2, 0> could all be used as a key in the map
for additional background the key in the map will be coordinates on a hex grid, and the value is what is currently stored at that location.
java generics collections
edited Nov 21 '18 at 4:21
Nicholas K
6,89761133
asked Nov 20 '18 at 3:39
jwmorsejwmorse
133
1
The right type needs to be able to accept duplicate values. What do you mean? Maps don't allow duplicate keys.
– shmosel
Nov 20 '18 at 3:43
maybe use a pair: stackoverflow.com/questions/156275/… ?
– Ray Tayek
Nov 20 '18 at 3:44
Or an Entry. Or make your type.
– shmosel
Nov 20 '18 at 3:45
can<1, 0>repeat multiple times as key in your case?
– secret super star
Nov 20 '18 at 3:55
@secretsuperstar no the combination of integers will always be unique.
– jwmorse
Nov 20 '18 at 3:59
add a comment |
I would like to use two generic types as a key for a hash map. Effectively:
Map<CollectionType<Integer, Integer>, Character> map = new HashMap<>();
I am trying to find if this is possible, and if so which collection type I could use. The right type needs to be able to accept duplicate values. i.e. <1, 0>, <1, 1>, <2, 0> could all be used as a key in the map
for additional background the key in the map will be coordinates on a hex grid, and the value is what is currently stored at that location.
java generics collections
edited Nov 21 '18 at 4:21
Nicholas K
6,89761133
asked Nov 20 '18 at 3:39
jwmorsejwmorse
133
I would like to use two generic types as a key for a hash map. Effectively:
Map<CollectionType<Integer, Integer>, Character> map = new HashMap<>();
I am trying to find if this is possible, and if so which collection type I could use. The right type needs to be able to accept duplicate values. i.e. <1, 0>, <1, 1>, <2, 0> could all be used as a key in the map
for additional background the key in the map will be coordinates on a hex grid, and the value is what is currently stored at that location.
java generics collections
java generics collections
edited Nov 21 '18 at 4:21
Nicholas K
6,89761133
asked Nov 20 '18 at 3:39
jwmorsejwmorse
133
edited Nov 21 '18 at 4:21
Nicholas K
6,89761133
asked Nov 20 '18 at 3:39
jwmorsejwmorse
133
edited Nov 21 '18 at 4:21
Nicholas K
6,89761133
edited Nov 21 '18 at 4:21
Nicholas K
6,89761133
edited Nov 21 '18 at 4:21
Nicholas K
6,89761133
6,89761133
asked Nov 20 '18 at 3:39
jwmorsejwmorse
133
asked Nov 20 '18 at 3:39
jwmorsejwmorse
133
asked Nov 20 '18 at 3:39
jwmorsejwmorse
133
133
1
The right type needs to be able to accept duplicate values. What do you mean? Maps don't allow duplicate keys.
– shmosel
Nov 20 '18 at 3:43
maybe use a pair: stackoverflow.com/questions/156275/… ?
– Ray Tayek
Nov 20 '18 at 3:44
Or an Entry. Or make your type.
– shmosel
Nov 20 '18 at 3:45
can<1, 0>repeat multiple times as key in your case?
– secret super star
Nov 20 '18 at 3:55
@secretsuperstar no the combination of integers will always be unique.
– jwmorse
Nov 20 '18 at 3:59
add a comment |
1
The right type needs to be able to accept duplicate values. What do you mean? Maps don't allow duplicate keys.
– shmosel
Nov 20 '18 at 3:43
maybe use a pair: stackoverflow.com/questions/156275/… ?
– Ray Tayek
Nov 20 '18 at 3:44
Or an Entry. Or make your type.
– shmosel
Nov 20 '18 at 3:45
can<1, 0>repeat multiple times as key in your case?
– secret super star
Nov 20 '18 at 3:55
@secretsuperstar no the combination of integers will always be unique.
– jwmorse
Nov 20 '18 at 3:59
1
1
The right type needs to be able to accept duplicate values. What do you mean? Maps don't allow duplicate keys.
– shmosel
Nov 20 '18 at 3:43
The right type needs to be able to accept duplicate values. What do you mean? Maps don't allow duplicate keys.
– shmosel
Nov 20 '18 at 3:43
maybe use a pair: stackoverflow.com/questions/156275/… ?
– Ray Tayek
Nov 20 '18 at 3:44
maybe use a pair: stackoverflow.com/questions/156275/… ?
– Ray Tayek
Nov 20 '18 at 3:44
Or an Entry. Or make your type.
– shmosel
Nov 20 '18 at 3:45
Or an Entry. Or make your type.
– shmosel
Nov 20 '18 at 3:45
can
<1, 0> repeat multiple times as key in your case?– secret super star
Nov 20 '18 at 3:55
can
<1, 0> repeat multiple times as key in your case?– secret super star
Nov 20 '18 at 3:55
@secretsuperstar no the combination of integers will always be unique.
– jwmorse
Nov 20 '18 at 3:59
@secretsuperstar no the combination of integers will always be unique.
– jwmorse
Nov 20 '18 at 3:59
add a comment |
1 Answer
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oldest
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Use a Pair<Integer, Integer>, provided by many libraries like in org.apache.commons.lang3.tuple.Pair or in jdk as javafx.util.Pair.
equals() and hashcode() are overridden, so it can work as a key in the Map.
Map<Pair<Integer, Integer>, Character> map = new HashMap<>();
answered Nov 20 '18 at 3:46
KartikKartik
3,22631435
add a comment |
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1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
Use a Pair<Integer, Integer>, provided by many libraries like in org.apache.commons.lang3.tuple.Pair or in jdk as javafx.util.Pair.
equals() and hashcode() are overridden, so it can work as a key in the Map.
Map<Pair<Integer, Integer>, Character> map = new HashMap<>();
answered Nov 20 '18 at 3:46
KartikKartik
3,22631435
add a comment |
Use a Pair<Integer, Integer>, provided by many libraries like in org.apache.commons.lang3.tuple.Pair or in jdk as javafx.util.Pair.
equals() and hashcode() are overridden, so it can work as a key in the Map.
Map<Pair<Integer, Integer>, Character> map = new HashMap<>();
answered Nov 20 '18 at 3:46
KartikKartik
3,22631435
add a comment |
Use a Pair<Integer, Integer>, provided by many libraries like in org.apache.commons.lang3.tuple.Pair or in jdk as javafx.util.Pair.
equals() and hashcode() are overridden, so it can work as a key in the Map.
Map<Pair<Integer, Integer>, Character> map = new HashMap<>();
answered Nov 20 '18 at 3:46
KartikKartik
3,22631435
Use a Pair<Integer, Integer>, provided by many libraries like in org.apache.commons.lang3.tuple.Pair or in jdk as javafx.util.Pair.
equals() and hashcode() are overridden, so it can work as a key in the Map.
Map<Pair<Integer, Integer>, Character> map = new HashMap<>();
answered Nov 20 '18 at 3:46
KartikKartik
3,22631435
answered Nov 20 '18 at 3:46
KartikKartik
3,22631435
answered Nov 20 '18 at 3:46
KartikKartik
3,22631435
answered Nov 20 '18 at 3:46
KartikKartik
3,22631435
3,22631435
add a comment |
add a comment |
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1
The right type needs to be able to accept duplicate values. What do you mean? Maps don't allow duplicate keys.
– shmosel
Nov 20 '18 at 3:43
maybe use a pair: stackoverflow.com/questions/156275/… ?
– Ray Tayek
Nov 20 '18 at 3:44
Or an Entry. Or make your type.
– shmosel
Nov 20 '18 at 3:45
can
<1, 0>repeat multiple times as key in your case?– secret super star
Nov 20 '18 at 3:55
@secretsuperstar no the combination of integers will always be unique.
– jwmorse
Nov 20 '18 at 3:59