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5.6.1.3.6 If-Else

Brace style for if-else statements

Brace style for if-else statements

Left brace { new line


Controls whether the left brace of if-else statements appears in a new line or not.


Setting left brace to a new line:

if (a < 10)                             
{                                       
    ...                                 


Do not set left brace to a new line:

if (a < 10) {                           
    ...                                 



Right brace } new line


Controls whether the right brace of if-else statements appears in a new line or not.


Setting right brace to a new line:

if (a < 10)                             
{                                       
    ...                                 
}                                       
else                                    
{                                       
    ...                                 
}                                       


Do not set right brace to a new line:

if (a < 10)                             
{                                       
    ...                                 
} else                                  
{                                       
    ...                                 
}                                       



Indent left brace {


Specifies the indentation size of left braces.


Setting left brace to a new line and using an indentation size of 4:

if·(a·<·10)                             
····{                                   
····...                                 


Setting left brace to a new line and using an indentation size of 0:

if·(a·<·10)                             
{                                       
    ...                                 


Do not set left brace to a new line and use indentation size of 1:

if·(a·<·10)·{                           
    ...                                 


Do not set left brace to a new line and use indentation size of 0:

if·(a·<·10){                            
    ...                                 



Indent right brace }


Specifies the indentation size of right braces.


Left brace is on a new line and set indentation size of 4 for left and right braces:

if·(a·<·10)                             
····{                                   
····...                                 
····}                                   


Left brace is on a new line and set indentation size of 0 for left and right braces:

if·(a·<·10)                             
{                                       
····...                                 
}                                       



Indent after right brace }


Controls indentation of right braces in if-else statements.


Do not set right brace to a new line and use an indentation size of 0:

if (a < 10)                             
{                                       
    ...                                 
}else                                   
{                                       
    ...                                 
}                                       


Do not set right brace to a new line and use an indentation size of 1:

if (a < 10)                             
{                                       
    ...                                 
} else                                  
{                                       
    ...                                 
}                                       



Cuddle braces of empty blocks {}


Specifies how to format braces of if-else blocks.


Cuddle braces of empty blocks:

if (condition) {}                       


Do not cuddle braces of empty blocks:

if (condition) {                        
}                                       



Indent cuddled braces {}


Controls the indentation size of cuddled braces.


Cuddle braces of empty blocks and use an indentation of 0:

if·(condition){}                        


Cuddle braces of empty blocks and use an indentation of 1:

if·(condition)·{}                       



Prohibit blank lines after left brace {


Prohibits blank lines directly after a left brace of if-else blocks.

Some code conventions require a blank line before each comment.
Such a formatting looks proper if the comment, for instance, appears between two statements.
But if a comment follows directly after a left brace of if-else blocks an unnecessary gap can appear.


Left brace of statement block is set to a new line using an indentation size of 0.
Additionally a blank line shall be inserted before comments:

if (a < 10)                             
{                                       
                                       
    // comment with a preceding blank line
    callAnotherMethod();                
                                       
    // another comment                  
    ...                                 
}                                       


In the example above the left brace and blank line before the comment seem to create an unnecessary gap.
To avoid such a gap just prohibit blank lines after left braces:

if (a < 10)                             
{                                       
    // comment with a preceding blank line
    callAnotherMethod();                
                                       
    // another comment                  
    ...                                 
}                                       

Now the blank line before the first comment disappeared and closed the gap, but all other comments still contain the expected blank line as usual.
Of course this works for all kind of blank lines and not only for blank lines before comments.

See also... See also: Jindent - Settings - Formatter - Java / SQLJ - Blank Lines - Comments , Jindent - Settings - Formatter - Java / SQLJ - Blank Lines




If number of lines in body is at least ... then insert blank line after {


Inserts an extra blank line after left braces of if-else statements containing a certain number of lines in their bodies.

Code conventions which prefer the K&R brace style (also known as Kernal, Java or Sun Style: do NOT put left brace to a new line) can run into a specific issue regarding readability of source code.


Let's assume the following source code example is formatted in a typical K&R brace style:

if (a < 10) {                           
    callMethod(--a);                    
}                                       
                                       
if (b < 10) {                           
    callMethodA(i);                     
    for (int i = 0; i < n; i++) {       
        callMethodB(i);                 
        callMethodC(i);                 
    }                                   
    callMethodD(i);                     
}                                       
                                       
if (x == 0) {                           
    callMethodA();                      
    callMethodB();                      
} else {                                
    callMethodC();                      
    callMethodD();                      
}                                       

In this case formatting of statement if (a < 10) looks fine, but statement if (b < 10) { seems to be formatted too tight: The statement head if (b < 10) { and the first block statement callMethodA(i); are connected too close and could cause confusion.
To avoid a too close formatting for specific if-else statements use setting "If number of lines in body is at least ... then insert blank line after {" to insert an extra blank line before the first block statement.


The same example as above, but now using setting "If number of lines in body is at least ... then insert blank line after {" with a value of 2.

if (a < 10) {                           
    callMethod(--a);                    
}                                       
                                       
if (b < 10) {                           
                                       
    callMethodA(i);                     
    for (int i = 0; i < n; i++) {       
        callMethodB(i);                 
        callMethodC(i);                 
    }                                   
    callMethodD(i);                     
}                                       
                                       
if (x == 0) {                           
                                       
    callMethodA();                      
    callMethodB();                      
} else {                                
                                       
    callMethodC();                      
    callMethodD();                      
}                                       

Now formatting of statement if (b < 10) { seems to be much clearer and statement if (a < 10) { is still formatted as before.
This setting counts the lines of code in every if-else body and if at least 2 lines are counted then an extra blank line is inserted after the left brace of if-else head.
With this setting typical small if-else statements can be kept compact, but statements with an extended body are formatted more spacious and clearer.


The same example again, but ""If number of lines in body is at least ... then insert blank line after {"" is set to value 3.

if (a < 10) {                           
    callMethod(--a);                    
}                                       
                                       
if (b < 10) {                           
                                       
    callMethodA(i);                     
    for (int i = 0; i < n; i++) {       
        callMethodB(i);                 
        callMethodC(i);                 
    }                                   
    callMethodD(i);                     
}                                       
                                       
if (x == 0) {                           
    callMethodA();                      
    callMethodB();                      
} else {                                
    callMethodC();                      
    callMethodD();                      
}                                       

Now statement if (x == 0) { is formatted in the same way as while (a < 10) {.


Using value 0:

if (a < 10) {                           
                                       
    callMethod(--a);                    
}                                       
                                       
if (b < 10) {                           
                                       
    callMethodA(i);                     
    for (int i = 0; i < n; i++) {       
        callMethodB(i);                 
        callMethodC(i);                 
    }                                   
    callMethodD(i);                     
}                                       
                                       
if (x == 0) {                           
                                       
    callMethodA();                      
    callMethodB();                      
} else {                                
                                       
    callMethodC();                      
    callMethodD();                      
}                                       

And all statements are formatted more spacious.

To turn this setting completely off just choose value infinite.



If number of lines in body is at least ... then insert blank line before }


Inserts an extra blank line before right braces of if-else statements containing a certain number of lines in their bodies.

This setting works exactly in the same way as "If number of lines in body is at least ... then insert blank line after {", but now the extra blank line will be inserted at the end of if-else statement bodies.


Let's assume "If number of lines in body is at least ... then insert blank line after {" is set to 2 and "If number of lines in body is at least ... then insert blank line before }" is set to 2 too:

if (a < 10) {                           
    callMethod(--a);                    
}                                       
                                       
if (b < 10) {                           
                                       
    callMethodA(i);                     
    for (int i = 0; i < n; i++) {       
        callMethodB(i);                 
        callMethodC(i);                 
    }                                   
    callMethodD(i);                     
                                       
}                                       
                                       
if (x == 0) {                           
                                       
    callMethodA();                      
    callMethodB();                      
                                       
} else {                                
                                       
    callMethodC();                      
    callMethodD();                      
                                       
}                                       

This setting creates an even more spacious formatting style.



Do not insert blank line before single left brace


This setting is related to the previous setting: "If number of lines in body is at least ... then insert blank line before }"
If insertion of an extra blank line before right braces is used, then this setting prohibits this extra blank line insertion before single right braces. A single right brace is a brace which appears in a single line without any other token:


if (a < 10) {                           
    callMethod(--a);                    
}                    // <- this right brace appears alone
                                       
if (a < 10) {                           
    callMethodA();                      
    callMethodB();                      
} else {             // <- this right brace does not appear alone
    callMethodC();                      
    callMethodC();                      
}                    // <- this right brace appears alone

The code example above shows that the right brace of } else { does not appear alone, it is directly followed by an else token.

Now the next code example shows the usage of this setting:


Let's recall the example from the previous setting section. There we assumed "If number of lines in body is at least ... then insert blank line after {" and "If number of lines in body is at least ... then insert blank line before }" are set to value 2.

if (a < 10) {                           
    callMethod(--a);                    
}                                       
                                       
if (b < 10) {                           
                                       
    callMethodA(i);                     
    for (int i = 0; i < n; i++) {       
        callMethodB(i);                 
        callMethodC(i);                 
    }                                   
    callMethodD(i);                     
                                       
}                                       
                                       
if (x == 0) {                           
                                       
    callMethodA();                      
    callMethodB();                      
                                       
} else {                                
                                       
    callMethodC();                      
    callMethodD();                      
                                       
}                                       

Actually this already looks nice spacious for if-else statements, but for all other simple if statements the extra blank lines before the right braces seems to be unnecessary.


Now we additionally use setting: "Do not insert blank line before single left brace" and prohibit extra blank lines before single right braces:

if (a < 10) {                           
    callMethod(--a);                    
}                                       
                                       
if (b < 10) {                           
                                       
    callMethodA(i);                     
    for (int i = 0; i < n; i++) {       
        callMethodB(i);                 
        callMethodC(i);                 
    }                                   
    callMethodD(i);                     
}                                       
                                       
if (x == 0) {                           
                                       
    callMethodA();                      
    callMethodB();                      
                                       
} else {                                
                                       
    callMethodC();                      
    callMethodD();                      
}                                       

Now the extra blank line was only inserted before } else { because this is the only case a right brace does not appear as a single brace.

So we finally have a well formatted output where no uncessary extra blank lines extend the source code.




See also... See also: Jindent - Settings - Formatter - Java / SQLJ - Braces Style - Presets