Java HashMap containsKey always false
- by Dennis
I have the funny situation, that I store a Coordinate into a HashMap<Coordinate, GUIGameField>.
Now, the strange thing about it is, that I have a fragment of code, which should guard, that no coordinate should be used twice. But if I debug this code:
if (mapForLevel.containsKey(coord)) {
throw new IllegalStateException("This coordinate is already used!");
} else {
...do stuff...
}
... the containsKey always returns false, although I stored a coordinate with a hashcode of 9731 into the map and the current coord also has the hashcode 9731.
After that, the mapForLevel.entrySet() looks like:
(java.util.HashMap$EntrySet) [(270,90)=gui.GUIGameField@29e357, (270,90)=gui.GUIGameField@ca470]
What could I have possibly done wrong? I ran out of ideas. Thanks for any help!
public class Coordinate {
int xCoord;
int yCoord;
public Coordinate(int x, int y) {
...store params in attributes...
}
...getters & setters...
@Override
public int hashCode() {
int hash = 1;
hash = hash * 41 + this.xCoord;
hash = hash * 31 + this.yCoord;
return hash;
}
}
