StatementNestingDepth.qhelp

<!DOCTYPE qhelp PUBLIC
  "-//Semmle//qhelp//EN"
  "qhelp.dtd">
<qhelp>
<overview>
<p>
A method that contains a high level of nesting can be very difficult to understand. As noted in 
[McConnell], the human brain cannot easily handle more than three levels of nested <code>if</code>
statements.</p>

</overview>
<recommendation>

<p>
Extract nested statements into new methods, for example by using the 'Extract Method' refactoring
from [Fowler].</p>

<p>
For more ways to reduce the level of nesting in a method, see [McConnell].
</p>

<p>
Furthermore, a method that has a high level of nesting often indicates that its design can be 
improved in other ways, as well as dealing with the nesting problem itself.
</p>

</recommendation>
<example>

<p>
In the following example, the code has four levels of nesting and is unnecessarily difficult to read.
</p>

<sample src="StatementNestingDepth.java" />

<p>
In the following modified example, some of the nested statements have been extracted into a new method
<code>PrintAllCharInts</code>.
</p>

<sample src="StatementNestingDepthGood.java" />

</example>
<references>


<li>
M. Fowler, <em>Refactoring</em>, pp. 89-95. Addison-Wesley, 1999.
</li>
<li>
S. McConnell, <em>Code Complete</em>, 2nd Edition, &sect;19.4. Microsoft Press, 2004.
</li>


</references>
</qhelp>