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.getC lass()))) 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