What's wrong with my hashCode() ?

[Jon Camilleri]

Public class Player {
...
public int hashCode() {
	int _hash = 7;
	
	int _cpCount = this.name.codePointCount(0, name.length());
	int _codePointV = 0;
	while (_cpCount < this.name.length()) {
		_codePointV += this.name.codePointAt(_cpCount);
		_cpCount++;
	}
...}

I am calling different instances, however, it returns the same hashCode() for different instances:

...
_log.debug(playerOne.hashCode());
...

returns
172 [main] DEBUG poker.Poker - 217
172 [main] DEBUG poker.Poker - 217
172 [main] DEBUG poker.Poker - 217

Not sure why they are being returned in triplicate either.

_log.debug(playerTwo.hashCode());

returns
172 [main] DEBUG poker.Poker - 217
...(x3)

[Henry Wong]

It would help if you print out more details -- such as "name" or other parts of the instance, in addition to the hash code. We don't know anything about the instances that you are referring to.

And BTW, it is valid for two unequal instances to have the same hash code -- so there may be nothing wrong.

Henry

[Jon Camilleri]

Henry Wong wrote:

It would help if you print out more details -- such as "name" or other parts of the instance, in addition to the hash code. We don't know anything about the instances that you are referring to.

And BTW, it is valid for two unequal instances to have the same hash code -- so there may be nothing wrong.

Henry

I think I resolved it now:

public class TestOne {


	public static void main(String[] args) {
		System.out.println(hashCode("Johnny"));
		System.out.println(hashCode("Johnny"));
		System.out.println(hashCode("Peter"));

	}
	
	public static int hashCode(String _name) {
		/* TODO: FIX/BUG.  Player.hashCode() returning the same hashCode() for different instances.
		 * */
		
		int _hash = 7;
		
		int _cpCount = _name.codePointCount(0, _name.length());
		//System.out.println("DEBUG" + _cpCount);
		int _codePointV = 0;
		//System.out.println("DEBUG" + _codePointV);
		for (_cpCount = 0; _cpCount < _name.codePointCount(0, _name.length()); _cpCount++) {
			_codePointV += _name.codePointAt(_cpCount);
			//System.out.println("DEBUG" + _cpCount);
		}
	_hash = _hash * 31 + _codePointV;  
	return _hash; 
	
}}

Output
847 for _name = "Johnny"
847 for _name = "Johnny"
729 for "_name = "Peter"

[Campbell Ritchie]

Why do you start your variable names with underscores?