How do I make 2 comparable methods in only one class?

Question

I've got one class, that I sort it already by one attribute. Now I need to make another thing, that I need to create another way to sort my data. How can I make it, so I can choose between the two methods. The only command I know is Collections.sort that will pick up the method compareTo from the class I want to compare its data.

Is it even possible?

Answer 1

What you need to do is implement a custom Comparator. And then use:

Collections.sort(yourList, new CustomComparator<YourClass>()); 

Specifically, you could write: (This will create an Anonymous class that implements Comparator.)

Collections.sort(yourList, new Comparator<YourClass>(){     public int compare(YourClass one, YourClass two) {         // compare using whichever properties of ListType you need     } }); 

You could build these into your class if you like:

class YourClass {      static Comparator<YourClass> getAttribute1Comparator() {         return new Comparator<YourClass>() {             // compare using attribute 1         };     }      static Comparator<YourClass> getAttribute2Comparator() {         return new Comparator<YourClass>() {             // compare using attribute 2         };     } } 

It could be used like so:

Collections.sort(yourList, YourClass.getAttribute2Comparator());