Code line wrapping - how to handle long lines

Question

I'm facing a particular line that is 153 characters long. Now, I tend to break things after 120 characters (of course, this is heavily dependent on where I am and the local conventions.) But to be honest, everywhere I break the line just makes it look bad. So I'm looking for some ideas on what I should do for it.

Here's the line:

private static final Map<Class<? extends Persistent>, PersistentHelper> class2helper = new HashMap<Class<? extends Persistent>, PersistentHelper>(); 

I'm open to both ideas about how/where to break the line (and why), as well as ways to shorten the line itself.

We're not a Java shop, and there aren't local conventions for this sort of thing, or obviously I would simply follow them.

Thanks!

Answer 1

In general, I break lines before operators, and indent the subsequent lines:

Map<long parameterization> longMap     = new HashMap<ditto>();  String longString = "some long text"                   + " some more long text"; 

To me, the leading operator clearly conveys that "this line was continued from something else, it doesn't stand on its own." Other people, of course, have different preferences.

Answer 2

This is how I do it, and Google does it my way.

• Break before the symbol for non-assignment operators.
• Break after the symbol for = and for ,.

In your case, since you're using 120 characters, you can break it after the assignment operator resulting in

private static final Map<Class<? extends Persistent>, PersistentHelper> class2helper =         new HashMap<Class<? extends Persistent>, PersistentHelper>(); 

In Java, and for this particular case, I would give two tabs (or eight spaces) after the break, depending on whether tabs or spaces are used for indentation.

This is of course a personal preference and if your project has its own convention for line-wrapping then that is what you should follow whether you like it or not.