how to make a set of array in java?

Question

Since the equals function in array only check the instance, it doesn\'t work well with Set. Hence, I wonder how to make a set of arrays in java?

One possible way cou

Answer 1

Since the ArrayList class already wraps an array, you can extend it and override the equals and hashCode methods. Here is a sample:

public MyArrayList extends ArrayList {

    @Override
    public boolean equals(Object o) {
        if (o instanceof MyArrayList) {
            //place your comparison logic here
            return true;
        }
        return false;
    }

    @Override
    public int hashCode() {
        //just a sample, you can place your own code
        return super.hashCode();
    }
}

UPDATE:

You can even override it for a generic use, just changing the code to:

public MyArrayList extends ArrayList {
    //overrides the methods you need
    @Override
    public boolean equals(Object o) {
        if (o instanceof MyArrayList) {
            //place your comparison logic here
            return true;
        }
        return false;
    }
}