Re: Casting an object in equals Java 5
crazzybugger wrote:
On Sep 30, 1:25 pm, Sabine Dinis Blochberger <no.s...@here.invalid>
wrote:
crazzybugger wrote:
Hi,
I am stuck with a compiler warning while trying to cast an
object inside equals method.
Consider class A<I>{ }
inside this class, I am trying to override equals method. However, I
am not able to cast the received object into the proper type without
compiler warning.
Consider this implementation of equals
public boolean equals(Object that){
if(that instanceof A){
A<I> that1 = this.getClass().cast(that); // here I am
getting compiler warning.
// perform comparisons...
}
}
what is the right way to cast here ?
thank you...
Since you already test if "that" is an instance of "A", do you even need
to cast it (assuming "A" is the class that implements this "equals()")?
A cast only tells the compiler to pretend/handle it as if that this
object is of type X, it does not convert the object in any way.
<http://mindprod.com/jgloss/cast.html>
If I donot cast it as an object of A<I> how can I access the methods &
attributes of A ?
You can't. But I don't understand your "this.getClass().cast(that);"
I'd try
A<I> that1 = (A<I>) that;
that1.methodOfA();
By the way, your choice of example variable names confuses me. I'd maybe
have chosen them like this ...
public boolean equals(Object object) {
if (object instanceof A) {
A<I> a = (A<I>) object;
...
Besides If I try casting it as object of type 'A'
and not as A<I>, I get the 'not parameterised' warning!!!
Which is as it should be, why would you expect anything else?
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