Super equals

[odwrotnie]

Hi,

I have a class Range with 2 fields (starts and ends), it overrides equals() method:

public boolean equals(Object o) {
        if(this == o)
            return true;
        if(o == null)
            return false;
        if(! (o instanceof Range))
            return false;
        Range r = (Range) o;
        if(this.starts.equals(r.starts) && this.ends.equals(r.ends))
            return true;
        return false;
    }

The class is extended by 2 other classes - Gap and Task which does not overrides equals().

In this example Task equals Gap with the same starts and ends fields... :/.

What are the solutions (besides overriding equals method in Task and Gap or comparing getClass() (if(! (this.getClass().equals(o.getClass()))) return false) in the Range.equals() method) to avoid it?

Thanks in advance,
Etam.

[JosAH]

There are no alternatives besides (partially) overriding the equals() method in
the two sub classes or handling it all in the super class equals() method.

kind regards,

Jos

[odwrotnie]

(...) or handling it all in the super class equals() method (...)

Do you mean:

if(! (this.getClass().equals(other.getClass())))
 return false;
 

?

Isn't it ineffective?

Thanks,
Pawel.

[JosAH]

Do you mean:

if(! (this.getClass().equals(other.getClass())))
 return false;
 

?

Isn't it ineffective?

Thanks,
Pawel.

Three method calls; the most expensive (probably) being the equals() method.
You can't do much better than that in your little three class hierarchy.

kind regards,

Jos