Returning a string representation of the number of albums and songs available

Question

What this method should do is return a String that displays how many albums and songs there are. This method is a private method of my Artist class which has a method called albumCount() and songCount(). The whole class probably needs an improvement but I will try that later. First I'd like this single method to be improved if possible.

public String toAlbumSongCount() {
    StringBuilder builder = new StringBuilder();

    final int albumCount = albumCount();
    final int songCount = songCount();

    builder.append( albumCount );
    //Append albums instead of album if albumCount is greater than 1
    builder.append( (albumCount > 1) ? " albums" : " album" );
    builder.append( "," ); //Move this to the line above?
    builder.append( songCount );
    //Append songs instead of song if songCount is greater than 1
    builder.append( (songCount > 1 ) ? " songs" : " song" );

    return builder.toString();
}

I used the StringBuilder class because I heard a dozen of times that it will improve performance when concatenating Strings. I wasn't sure about those two lines :

builder.append( (albumCount > 1) ? " albums" : " album" );
builder.append( (songCount > 1 ) ? " songs" : " song" );

Are they good enough with the comments above them?

I appreciate any help even if it means completely rewriting this method.

Answer 1

I don't think these are any major improvements, but there are many small things that I would change.

• albumCount and songCount is both the name of a variable, and of a method
• Pluralization can be extracted to a separate method
• Remove unnecessary comments and spaces

So here's what I would do:

public String toAlbumSongCount() {
    StringBuilder builder = new StringBuilder();
    final int albumCount = getAlbumCount();
    final int songCount = getSongCount();

    builder.append(albumCount);
    builder.append(pluralize(albumCount, " album", " albums"));
    builder.append(", ");
    builder.append(songCount);
    builder.append(pluralize(songCount, " song", " songs"));

    return builder.toString();
}

private static final String pluralize(int count, String singular, String plural) {
    return count == 1 ? singular : plural;
}

A tiny extra thing that is often forgotten is to pass an argument to the StringBuilder, by default it is initialized with a capacity of 16 characters. If we look at a little example, 99 albums, 999 songs we see that that's 20 characters. So the internal array in AbstractStringBuilder will need to be resized once. We could create the StringBuilder with a capacity of 24 to reduce the need for the resize.

StringBuilder builder = new StringBuilder(24);

Answer 2

Text manipulation like that is always a pain. I like to extract functions for things like this, though.

private static final String simplePlural (int count, String noun) {
    if (count == 1) {
        return "1 " + noun;
    }
    return count + " " + noun + "s";
}

With that function, your code becomes:

public String toAlbumSongCount() {
    return simplePlural(albumCount(), "album") 
       + ", " + simplePlural(songCount(), "song");
}

I know there's no StringBuilder in there, but the performance benefit for something that's seldom used, will be negligible, and this is more readable.

Note that the code above adds a space after the comma, which your code is missing.

Answer 3

If you want to keep the StringBuilder, you use its fluent interface like this to remove some clutter.

    builder.append("first")
       .append("second")
       .toString();

BTW, there is also some support in Java for pluralization and so on, but I have to admit I have never used it because in most cases it is really simpler to use a simple if. But if you want the perfect, maybe a bit overengineered solution for internationalization, you can have a look at ChoiceFormat

Answer 4

I would use Java's built-in message formatting method, MessageFormat. It has a means to select different text choices based on a number:

public String toAlbumSongCount() {      
    return MessageFormat.format(
        "{0,number} {0,choice,1#album|1<albums},{1,number} {1,choice,1#song|1<songs}",
        albumCount(), // parameter 0
        songCount()); // parameter 1
}