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 lt Class lt   extends Persistent gt   PersistentHelper gt  class2helper   new HashMap lt Class lt   extends Persistent gt   PersistentHelper gt       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

User · Answer

IMHO this is the best way to write your line :

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

This way the increased indentation without any braces can help you to see that the code was just splited because the line was too long. And instead of 4 spaces, 8 will make it clearer.

User · Answer

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 lt Class lt   extends Persistent gt   PersistentHelper gt  class2helper           new HashMap lt Class lt   extends Persistent gt   PersistentHelper gt       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

User · Answer

I think that moving last operator to the beginning of the next line is a good practice  That way you know right away the purpose of the second line  even it doesn t start with an operator  I also recommend 2 indentation spaces  2 tabs  for a previously broken tab  to differ it from the normal indentation  That is immediately visible as continuing previous line  Therefore I suggest this   private static final Map lt Class lt   extends Persistent gt   PersistentHelper gt  class2helper                new HashMap lt Class lt   extends Persistent gt   PersistentHelper gt

User · Answer

In general  I break lines before operators  and indent the subsequent lines   Map lt long parameterization gt  longMap       new HashMap lt ditto gt      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

User · Answer

Uses Guava s static factory methods for Maps and is only 105 characters long   private static final Map lt Class lt   extends Persistent gt   PersistentHelper gt  class2helper   Maps newHashMap

[java] Code line wrapping - how to handle long lines

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