347 lines
10 KiB
HTML
347 lines
10 KiB
HTML
<?xml version="1.0" encoding="UTF-8"?>
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<!DOCTYPE html
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PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
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"DTD/xhtml1-strict.dtd">
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<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
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<head>
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<title>Metrics Checks</title>
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<link rel="stylesheet" type="text/css" href="mystyle.css"/>
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</head>
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<body>
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<!-- The header -->
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<table border="0" width="100%" summary="header layout">
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<tr>
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<td><h1>Metrics Checks</h1></td>
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<td align="right"><img src="logo.png" alt="Checkstyle Logo"/></td>
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</tr>
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</table>
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<!-- content -->
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<table border="0" width="100%" cellpadding="5" summary="body layout">
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<tr>
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<!--Left menu-->
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<td class="menu" valign="top">
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<ul>
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<li><a href="#BooleanExpressionComplexity">BooleanExpressionComplexity</a></li>
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<li><a href="#ClassDataAbstractionCoupling">ClassDataAbstractionCoupling</a></li>
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<li><a href="#ClassFanOutComplexity">ClassFanOutComplexity</a></li>
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<li><a href="#CyclomaticComplexity">CyclomaticComplexity</a></li>
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<li><a href="#NPathComplexity">NPathComplexity</a></li>
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</ul>
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</td>
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<!--Content-->
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<td class="content" valign="top" align="left">
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<!-- --><a name="BooleanExpressionComplexity"></a>
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<h2>BooleanExpressionComplexity</h2>
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<h4>Description</h4>
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<p class="body">
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Restrict the number of number of <span class="code">&&</span>,
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<span class="code">||</span> and <span class="code">^</span> in
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an expression.
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</p>
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<p>
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Rationale:
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Too many conditions leads to code that is difficult to
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read and hence debug and maintain.
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</p>
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<h4>Properties</h4>
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<table width="100%" border="1" cellpadding="5" class="body">
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<tr class="header">
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<th>name</th>
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<th>description</th>
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<th>type</th>
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<th>default value</th>
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</tr>
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<tr>
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<td>max</td>
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<td>the maximum allowed number of boolean operations in one
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experession.</td>
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<td><a href="property_types.html#integer">integer</a></td>
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<td><span class="default">3</span></td>
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</tr>
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</table>
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<h4>Examples</h4>
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<p class="body">
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To configure the check:
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</p>
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<pre class="body">
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<module name="BooleanExpressionComplexity"/>
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</pre>
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<p class="body">
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To configure the check with 7 allowed operation in boolean expression:
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</p>
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<pre class="body">
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<module name="BooleanExpressionComplexity">
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<property name="max" value="7"/>
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</module>
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</pre>
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<h4>Package</h4>
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<p class="body">
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com.puppycrawl.tools.checkstyle.checks.metrics
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</p>
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<h4>Parent Module</h4>
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<p class="body">
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<a href="config.html#treewalker">TreeWalker</a>
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</p>
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<!-- --><a name="ClassDataAbstractionCoupling"></a> <h2>ClassDataAbstractionCoupling</h2>
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<h4>Description</h4>
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<p class="body">
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This metric measures the number of instantiations of
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other classes within the given class. This type of
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coupling is not caused by inheritance or the object
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oriented paradigm. Generally speaking, any abstract
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data type with other abstract data types as members has
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data abstraction coupling; therefore, if a class has a
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local variable that is an instantiation (object) of
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another class, there is data abstraction coupling. The
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higher the DAC, the more complex the data structure
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(classes) of the system.
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</p>
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<h4>Properties</h4>
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<table width="100%" border="1" cellpadding="5" class="body">
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<tr class="header">
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<th>name</th>
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<th>description</th>
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<th>type</th>
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<th>default value</th>
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</tr>
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<tr>
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<td>max</td>
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<td>the maximum threshold allowed</td>
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<td><a href="property_types.html#integer">integer</a></td>
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<td><span class="default">7</span></td>
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</tr>
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</table>
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<h4>Examples</h4>
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<p class="body">
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To configure the check:
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</p>
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<pre class="body">
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<module name="ClassDataAbstractionCoupling"/>
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</pre>
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<p class="body">
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To configure the check with a threshold of 5:
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</p>
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<pre class="body">
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<module name="ClassDataAbstractionCoupling">
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<property name="max" value="5"/>
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</module>
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</pre>
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<h4>Package</h4>
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<p class="body">
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com.puppycrawl.tools.checkstyle.checks.metrics
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</p>
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<h4>Parent Module</h4>
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<p class="body">
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<a href="config.html#treewalker">TreeWalker</a>
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</p>
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<!-- --><a name="ClassFanOutComplexity"></a> <h2>ClassFanOutComplexity</h2>
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<h4>Description</h4>
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<p class="body">
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The number of other classes a given class relies on. Also
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the square of this has been shown to indicate the
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amount of maintenence required in functional programs
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(on a file basis) at least.
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</p>
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<h4>Properties</h4>
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<table width="100%" border="1" cellpadding="5" class="body">
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<tr class="header">
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<th>name</th>
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<th>description</th>
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<th>type</th>
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<th>default value</th>
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</tr>
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<tr>
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<td>max</td>
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<td>the maximum threshold allowed</td>
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<td><a href="property_types.html#integer">integer</a></td>
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<td><span class="default">20</span></td>
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</tr>
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</table>
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<h4>Examples</h4>
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<p class="body">
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To configure the check:
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</p>
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<pre class="body">
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<module name="ClassFanOutComplexity"/>
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</pre>
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<p class="body">
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To configure the check with a threshold of 10:
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</p>
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<pre class="body">
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<module name="ClassFanOutComplexity">
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<property name="max" value="10"/>
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</module>
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</pre>
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<h4>Package</h4>
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<p class="body">
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com.puppycrawl.tools.checkstyle.checks.metrics
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</p>
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<h4>Parent Module</h4>
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<p class="body">
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<a href="config.html#treewalker">TreeWalker</a>
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</p>
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<!-- --><a name="CyclomaticComplexity"></a> <h2>CyclomaticComplexity</h2>
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<h4>Description</h4>
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<p class="body">
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Checks cyclomatic complexity against a specified limit. The complexity is
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measured by the number of
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<span CLASS="code">if</span>,
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<span CLASS="code">while</span>,
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<span CLASS="code">do</span>,
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<span CLASS="code">for</span>,
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<span CLASS="code">?:</span>,
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<span CLASS="code">catch</span>,
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<span CLASS="code">switch</span>,
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<span CLASS="code">case</span> statements, and operators
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<span CLASS="code">&&</span> and <span CLASS="code">||</span> (plus one) in the body of a
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constructor, method, static initializer, or instance initializer.
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It is a measure of the minimum number of possible paths through the
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source and therefore the number of required tests. Generally 1-4 is
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considered good, 5-7 ok, 8-10 consider re-factoring, and 11+ re-factor now!
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</p>
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<h4>Properties</h4>
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<table width="100%" border="1" cellpadding="5" class="body">
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<tr class="header">
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<th>name</th>
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<th>description</th>
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<th>type</th>
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<th>default value</th>
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</tr>
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<tr>
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<td>max</td>
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<td>the maximum threshold allowed</td>
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<td><a href="property_types.html#integer">integer</a></td>
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<td><span class="default">10</span></td>
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</tr>
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</table>
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<h4>Examples</h4>
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<p class="body">
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To configure the check:
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</p>
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<pre class="body">
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<module name="CyclomaticComplexity"/>
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</pre>
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<p class="body">
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To configure the check with a threshold of 7:
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</p>
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<pre class="body">
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<module name="CyclomaticComplexity">
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<property name="max" value="7"/>
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</module>
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</pre>
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<h4>Package</h4>
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<p class="body">
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com.puppycrawl.tools.checkstyle.checks.metrics
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</p>
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<h4>Parent Module</h4>
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<p class="body">
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<a href="config.html#treewalker">TreeWalker</a>
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</p>
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<!-- --><a name="NPathComplexity"></a> <h2>NPathComplexity</h2>
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<h4>Description</h4>
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<p class="body">
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The NPATH metric computes the number of possible
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execution paths through a function. It takes into
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account the nesting of conditional statements and
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multi-part boolean expressions (e.g., A && B, C || D,
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etc.).
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</p>
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<p>
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Rationale:
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Nejmeh says that his group had an informal NPATH limit
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of 200 on individual routines; functions that exceeded
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this value were candidates for further decomposition -
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or at least a closer look.
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</p>
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<h4>Properties</h4>
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<table width="100%" border="1" cellpadding="5" class="body">
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<tr class="header">
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<th>name</th>
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<th>description</th>
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<th>type</th>
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<th>default value</th>
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</tr>
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<tr>
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<td>max</td>
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<td>the maximum threshold allowed</td>
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<td><a href="property_types.html#integer">integer</a></td>
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<td><span class="default">200</span></td>
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</tr>
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</table>
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<h4>Examples</h4>
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<p class="body">
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To configure the check:
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</p>
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<pre class="body">
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<module name="NPathComplexity"/>
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</pre>
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<p class="body">
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To configure the check with a threshold of 20:
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</p>
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<pre class="body">
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<module name="NPathComplexity">
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<property name="max" value="20"/>
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</module>
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</pre>
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<h4>Package</h4>
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<p class="body">
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com.puppycrawl.tools.checkstyle.checks.metrics
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</p>
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<h4>Parent Module</h4>
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<p class="body">
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<a href="config.html#treewalker">TreeWalker</a>
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</p>
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</td>
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</tr>
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</table>
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<hr />
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<div><a href="index.html">Back to the Checkstyle Home Page</a></div>
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<p class="copyright">
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Copyright © 2002-2003 Oliver Burn. All rights Reserved.
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</p>
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</body>
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</html>
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