how to make equal objects?

[Gabe Herbert]

I'm trying to figure out what what would enable two objects to qualify as "equal"...
When I create two Integer's they are equal, but when I create two of TPVEvent, which simply holds 3 variables, the objects do not equal!

Would someone explain this to me?

 
 class IntCompare {
 
public static void main(String[] args) {
Integer int1 = new Integer(42);
Integer int2 = new Integer(42);
 
TPVEvent tpv1 = new TPVEvent(1, 2, 3);
TPVEvent tpv2 = new TPVEvent(1, 2, 3);
 
System.out.println(int1.equals(int2) ); //returns true
System.out.println(tpv1.equals(tpv2) ); //returns false
}
 

}
 

class TPVEvent {
int t;
int p;
int v;
  
public TPVEvent(int t, int p, int v) {
this.t = t;
this.p = p;
this.v = v;
}
}

[Christophe Verré]

You need to override the equals() method of the Object class.
For details :
http://www.geocities.com/technofundo/tech/java/equalhash.html

[Ulf Dittmer]

... and, as that article points out, the hashCode() method as well.