What's the point of having Booking implements comparable?

[yongchein-o]

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Description of the question / problem here. Hi does anyone know what is the point of implementing comparable? If I have an ImList of Booking, how do I sort it using the fact that Booking implemented comparable?

I'd expect that there might be a sort method to like Sort an ImList of Bookings at Level 6....

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[LauWyeRock]

Comparable interface tells Java how to compare instances of classes that you have defined. Imlist::sort() takes in a comparator, so you still have to create a comparator class and use your compareTo (from comparable) to tell java how you want to sort the list. I think the point is just to simplify code? Like to abide by abstraction and encapsulation.

[celine-chung]

Referring to Lecture 5 slide 14, you need to create a class that implements Comparator which contains a single method compare(Booking x, Booking y) similar to the compareTo method of the Comparable interface which you defined in booking. In level 6 you can then use the ImList sort method by taking in the comparator class you implemented to sort your bookings!

It might seem redundant to define methods for both Comparator and Comparable, but as LauWyeRock mentioned, I believe it is probably to abide by encapsulation to have it clearly defined within the Booking class itself

[jlee1007]

I would believe that Comparable also helps to simplify the comparing process as it sorts by checking whether the difference between two values are negative, == to 0 or positive. Hence you can use very simple code like turn this.A - other.A;

[StanleyMak]

Alternatively, you can use comparator. I find it easier in my opinion. Comparator works very similarly to comparable when you define the method. Note that comparator uses a "compare(Booking b1, Booking b2)" while comparable uses a "compareTo". if you use comparator, make sure to initialise it in the jsh file: "BookingComparator bkComp = new BookingComparator();" and you can proceed to just "bookings = bookings.sort(bkComp);"

[ghost]

Alternatively, you can use comparator. I find it easier in my opinion. Comparator works very similarly to comparable when you define the method. Note that comparator uses a "compare(Booking b1, Booking b2)" while comparable uses a "compareTo". if you use comparator, make sure to initialise it in the jsh file: "BookingComparator bkComp = new BookingComparator();" and you can proceed to just "bookings = bookings.sort(bkComp);"

Or you can use a lambda expression without creating the BookingComparator class