Question

I have just started using google’s Guava collection (ComparisonChain and Objects). In my pojo I am overiding the equals method, so I did this first:

return ComparisonChain.start()
         .compare(this.id, other.id)
         .result() == 0;

However, I then realized that I could also use this :

return Objects.equal(this.id, other.id);

And I fail to see when comparison chain would be better as you can easily add further conditions like so:

return Objects.equal(this.name, other.name) 
       && Objects.equal(this.number, other.number);

The only benefit I can see if you specifically need an int returned. It has two extra method calls (start and result) and is more complex to a noob.

Are there obvious benefits of ComparisonChain I missing ?

(Yes, I am also overriding hashcode with appropriate Objects.hashcode())

Answer 1

ComparisonChain allow you to check whether an object is less-than or greater-than another object by comparing multiple properties (like sorting a grid by multiple columns).
It should be used when implementing Comparable or Comparator.

Objects.equal can only check for equality.