CODEWITHSUNDEEP
java
DeCampbell
DeCampbell

Reputation: 29

Which out of the two code fragments would be better to implement for a comparator?

I wanted to know what would be the best way to implement the comparator method following best practice?

I implemented one and someone else implemented the other.

Please any advice on which is more suitable would be great!

public class Product
{
public Product (String name, int weight) {

        this.name = name;
        this.weight = weight; 

    }

    public static final Comparator<Product> BY_WEIGHT = new Comparator<Product>() {

        public int compare(final Product weight1, final Product weight2) {

            return weight1.weight - weight2.weight;
        }
    };

    public String getName() {
        return name;
    }

    public int getWeight() {
        return weight;
    }
}

or

public class Product {

    private final String name;
    private final int weight;

    public Product (String name, int weight) {

        this.name = name;
        this.weight = weight; 

    }

    public static final Comparator<Product> BY_WEIGHT = new Comparator<Product>(){

        public int compare (final Product p1, final Product p2) {

            return Integer.compare(p1.getWeight(), p2.getWeight());
        }

    };

    public String getName() {
        return name;
    }

    public int getWeight() {
        return weight;
    }

Upvotes: 1

Views: 92

Answers (2)

Benoit
Benoit

Reputation: 5394

The second option, for reason already mentioned by @Eran.

This version uses built-in comparator:

    public static final Comparator<Product> BY_WEIGHT =
            Comparator.comparingInt(Product::getWeight);

Upvotes: 0

Eran
Eran

Reputation: 393936

The return weight1.weight - weight2.weight implementation has a risk of numeric overflow, so it might misbehave for some inputs (though it's probably safe to assume a Product's weight doesn't go anywhere near Integer.MAX_VALUE or Integer.MIN_VALUE, so that implementation will probably work fine) .

In general Integer.compare(p1.getWeight(), p2.getWeight()) is the better implementation, since it can't overflow (it returns (x < y) ? -1 : ((x == y) ? 0 : 1)).

Upvotes: 4

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