可比-compareTo方法

Question

I've been working on my own compareTo method which sorts a list of entered strings via the command line. The method needs to organise the strings from largest to smallest. If more than one string are equal in length, arrange alphabetically.

So far I have:

public int compareTo(LengthSortableString anotherSortable) {
    if (anotherSortable.getContents().length() > sortableString.length()) {
        return 1;
    } else if (anotherSortable.getContents().length() == sortableString.length()) {
        return 0;
    } else {
        return -1;
    }
}

Now I was curious if it was possible to sort the equal strings alphabetically without having to iterate through the equal strings looking for a char of different values.

** sortableString.getContents just returns a string type of the entered LengthSortableString.

Answer 1

In the case where the two lengths are equal, just return the alphabetical comparison:

else if (/* equal lengths */) {
    return str1.compareTo(str2);  // i.e. using compareTo of String
}

str1 and str2 represent the underlying String s of your LengthSortableString instances.

Answer 2

String already implements Comparable, so simply use anotherSortable.getContents().compareTo(sortableString); :

public int compareTo(LengthSortableString anotherSortable) {
    int byLength = Integer.valueOf(anotherSortable.getContents().length()).compareTo(sortableString.length());
    if (byLength != 0) {
        return byLength;
    }
    return anotherSortable.getContents().compareTo(sortableString);
}