SourceForge: checkstyle/checkstyle: src/xdocs/config

     1 <?xml version="1.0" encoding="ISO-8859-1"?>

     3 <document>

     5   <properties>

     6     <title>Metrics</title>

     7     <author>Checkstyle Development Team</author>

     8   </properties>

    10   <body>

    12     <section name="BooleanExpressionComplexity">

    13       <subsection name="Description">

    14         <p>

    15           Restrict the number of number of <span

    16           class="code">&#x26;&#x26;</span>, <span class="code">||</span>,

    17           <span class="code">&#x26;</span>, <span class="code">|</span>

    18           and <span class="code">^</span> in an expression.

    19         </p>

    21         <p>

    22           Rationale: Too many conditions leads to code that is difficult

    23           to read and hence debug and maintain.

    24         </p>

    26         <p>

    27           Note that the operators <span class="code">&#x26;</span> and

    28           <span class="code">|</span> are not only integer bitwise operators, they are also the

    29           <a href="http://java.sun.com/docs/books/jls/third_edition/html/expressions.html#15.22.2">

    30           non-shortcut versions</a> of the boolean operators

    31           <span class="code">&#x26;&#x26;</span> and <span class="code">||</span>.

    32         </p>

    33       </subsection>

    35       <subsection name="Properties">

    36         <table>

    37           <tr>

    38             <th>name</th>

    39             <th>description</th>

    40             <th>type</th>

    41             <th>default value</th>

    42           </tr>

    43           <tr>

    44             <td>max</td>

    45             <td>

    46               the maximum allowed number of boolean operations in one

    47               expression.

    48             </td>

    49             <td><a href="property_types.html#integer">integer</a></td>

    50             <td><span class="default">3</span></td>

    51           </tr>

    52           <tr>

    53             <td>tokens</td>

    54             <td>tokens to check</td>

    55             <td>

    56               subset of tokens

    57               <a href="api/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#LAND">LAND</a>,

    58               <a href="api/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#BAND">BAND</a>,

    59               <a href="api/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#LOR">LOR</a>,

    60               <a href="api/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#BOR">BOR</a>,

    61               <a href="api/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#BXOR">BXOR</a>

    62             </td>

    63             <td>

    64               <a href="api/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#LAND">LAND</a>,

    65               <a href="api/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#BAND">BAND</a>,

    66               <a href="api/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#LOR">LOR</a>,

    67               <a href="api/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#BOR">BOR</a>,

    68               <a href="api/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#BXOR">BXOR</a>

    69             </td>

    70           </tr>

    71         </table>

    72       </subsection>

    74       <subsection name="Examples">

    75         <p>

    76           To configure the check:

    77         </p>

    78         <source>

    79 &lt;module name=&quot;BooleanExpressionComplexity&quot;/&gt;

    80         </source>

    82         <p>

    83           To configure the check with 7 allowed operation in boolean

    84           expression:

    85         </p>

    86         <source>

    87 &lt;module name=&quot;BooleanExpressionComplexity&quot;&gt;

    88     &lt;property name=&quot;max&quot; value=&quot;7&quot;/&gt;

    89 &lt;/module&gt;

    90         </source>

    92         <p>

    93           To configure the check to ignore <span class="code">&#x26;</span> and

    94           <span class="code">|</span>:

    95         </p>

    96         <source>

    97 &lt;module name="BooleanExpressionComplexity"&gt;

    98     &lt;property name="tokens" value="BXOR,LAND,LOR"/&gt;

    99 &lt;/module&gt;

   100         </source>

   102       </subsection>

   104       <subsection name="Package">

   105         <p>

   106           com.puppycrawl.tools.checkstyle.checks.metrics

   107         </p>

   108       </subsection>

   110       <subsection name="Parent Module">

   111         <p>

   112           <a href="config.html#treewalker">TreeWalker</a>

   113         </p>

   114       </subsection>

   115     </section>

   117     <section name="ClassDataAbstractionCoupling">

   118       <subsection name="Description">

   119         <p>

   120           This metric measures the number of instantiations of other

   121           classes within the given class. This type of coupling is not

   122           caused by inheritance or the object oriented

   123           paradigm. Generally speaking, any abstract data type with

   124           other abstract data types as members has data abstraction

   125           coupling; therefore, if a class has a local variable that is

   126           an instantiation (object) of another class, there is data

   127           abstraction coupling. The higher the DAC, the more complex the

   128           data structure (classes) of the system.

   129         </p>

   130       </subsection>

   132       <subsection name="Properties">

   133         <table>

   134           <tr>

   135             <th>name</th>

   136             <th>description</th>

   137             <th>type</th>

   138             <th>default value</th>

   139           </tr>

   140           <tr>

   141             <td>max</td>

   142             <td>the maximum threshold allowed</td>

   143             <td><a href="property_types.html#integer">integer</a></td>

   144             <td><span class="default">7</span></td>

   145           </tr>

   146         </table>

   147       </subsection>

   149       <subsection name="Examples">

   150         <p>

   151           To configure the check:

   152         </p>

   153         <source>

   154 &lt;module name=&quot;ClassDataAbstractionCoupling&quot;/&gt;

   155         </source>

   157         <p>

   158           To configure the check with a threshold of 5:

   159         </p>

   160         <source>

   161 &lt;module name=&quot;ClassDataAbstractionCoupling&quot;&gt;

   162     &lt;property name=&quot;max&quot; value=&quot;5&quot;/&gt;

   163 &lt;/module&gt;

   164         </source>

   165       </subsection>

   167       <subsection name="Package">

   168         <p>

   169           com.puppycrawl.tools.checkstyle.checks.metrics

   170         </p>

   171       </subsection>

   173       <subsection name="Parent Module">

   174         <p>

   175           <a href="config.html#treewalker">TreeWalker</a>

   176         </p>

   177       </subsection>

   178     </section>

   180     <section name="ClassFanOutComplexity">

   181       <subsection name="Description">

   182         <p>

   183           The number of other classes a given class relies on. Also the

   184           square of this has been shown to indicate the amount of

   185           maintenence required in functional programs (on a file basis)

   186           at least.

   187         </p>

   188       </subsection>

   190       <subsection name="Properties">

   191         <table>

   192           <tr>

   193             <th>name</th>

   194             <th>description</th>

   195             <th>type</th>

   196             <th>default value</th>

   197           </tr>

   198           <tr>

   199             <td>max</td>

   200             <td>the maximum threshold allowed</td>

   201             <td><a href="property_types.html#integer">integer</a></td>

   202             <td><span class="default">20</span></td>

   203           </tr>

   204         </table>

   205       </subsection>

   207       <subsection name="Examples">

   208         <p>

   209           To configure the check:

   210         </p>

   211         <source>

   212 &lt;module name=&quot;ClassFanOutComplexity&quot;/&gt;

   213         </source>

   215         <p>

   216           To configure the check with a threshold of 10:

   217         </p>

   218         <source>

   219 &lt;module name=&quot;ClassFanOutComplexity&quot;&gt;

   220     &lt;property name=&quot;max&quot; value=&quot;10&quot;/&gt;

   221 &lt;/module&gt;

   222         </source>

   223       </subsection>

   225       <subsection name="Package">

   226         <p>

   227           com.puppycrawl.tools.checkstyle.checks.metrics

   228         </p>

   229       </subsection>

   231       <subsection name="Parent Module">

   232         <p>

   233           <a href="config.html#treewalker">TreeWalker</a>

   234         </p>

   235       </subsection>

   236     </section>

   238     <section name="CyclomaticComplexity">

   239       <subsection name="Description">

   240         <p>

   241           Checks cyclomatic complexity against a specified limit. The

   242           complexity is measured by the number of <span

   243           CLASS="code">if</span>, <span CLASS="code">while</span>, <span

   244           CLASS="code">do</span>, <span CLASS="code">for</span>, <span

   245           CLASS="code">?:</span>, <span CLASS="code">catch</span>, <span

   246           CLASS="code">switch</span>, <span CLASS="code">case</span>

   247           statements, and operators <span

   248           CLASS="code">&#x26;&#x26;</span> and <span

   249           CLASS="code">||</span> (plus one) in the body of a

   250           constructor, method, static initializer, or instance

   251           initializer.  It is a measure of the minimum number of

   252           possible paths through the source and therefore the number of

   253           required tests. Generally 1-4 is considered good, 5-7 ok, 8-10

   254           consider re-factoring, and 11+ re-factor now!

   255         </p>

   256       </subsection>

   258       <subsection name="Properties">

   259         <table>

   260           <tr>

   261             <th>name</th>

   262             <th>description</th>

   263             <th>type</th>

   264             <th>default value</th>

   265           </tr>

   266           <tr>

   267             <td>max</td>

   268             <td>the maximum threshold allowed</td>

   269             <td><a href="property_types.html#integer">integer</a></td>

   270             <td><span class="default">10</span></td>

   271           </tr>

   272         </table>

   273       </subsection>

   275       <subsection name="Examples">

   276         <p>

   277           To configure the check:

   278         </p>

   279         <source>

   280 &lt;module name=&quot;CyclomaticComplexity&quot;/&gt;

   281         </source>

   283         <p>

   284           To configure the check with a threshold of 7:

   285         </p>

   286         <source>

   287 &lt;module name=&quot;CyclomaticComplexity&quot;&gt;

   288     &lt;property name=&quot;max&quot; value=&quot;7&quot;/&gt;

   289 &lt;/module&gt;

   290         </source>

   291       </subsection>

   293       <subsection name="Package">

   294         <p>

   295           com.puppycrawl.tools.checkstyle.checks.metrics

   296         </p>

   297       </subsection>

   299       <subsection name="Parent Module">

   300         <p>

   301           <a href="config.html#treewalker">TreeWalker</a>

   302         </p>

   303       </subsection>

   304     </section>

   306     <section name="NPathComplexity">

   307       <subsection name="Description">

   308         <p>

   309           The NPATH metric computes the number of possible execution

   310           paths through a function. It takes into account the nesting of

   311           conditional statements and multi-part boolean expressions

   312           (e.g., A &amp;&amp; B, C || D, etc.).

   313         </p>

   315         <p>

   316           Rationale: Nejmeh says that his group had an informal NPATH

   317           limit of 200 on individual routines; functions that exceeded

   318           this value were candidates for further decomposition - or at

   319           least a closer look.

   320         </p>

   321       </subsection>

   323       <subsection name="Properties">

   324         <table>

   325           <tr>

   326             <th>name</th>

   327             <th>description</th>

   328             <th>type</th>

   329             <th>default value</th>

   330           </tr>

   331           <tr>

   332             <td>max</td>

   333             <td>the maximum threshold allowed</td>

   334             <td><a href="property_types.html#integer">integer</a></td>

   335             <td><span class="default">200</span></td>

   336           </tr>

   337         </table>

   338       </subsection>

   340       <subsection name="Examples">

   341         <p>

   342           To configure the check:

   343         </p>

   344         <source>

   345 &lt;module name=&quot;NPathComplexity&quot;/&gt;

   346         </source>

   348         <p>

   349           To configure the check with a threshold of 20:

   350         </p>

   351         <source>

   352 &lt;module name=&quot;NPathComplexity&quot;&gt;

   353     &lt;property name=&quot;max&quot; value=&quot;20&quot;/&gt;

   354 &lt;/module&gt;

   355         </source>

   356       </subsection>

   358       <subsection name="Package">

   359         <p>

   360           com.puppycrawl.tools.checkstyle.checks.metrics

   361         </p>

   362       </subsection>

   364       <subsection name="Parent Module">

   365         <p>

   366           <a href="config.html#treewalker">TreeWalker</a>

   367         </p>

   368       </subsection>

   369     </section>

   371     <section name="JavaNCSS">

   372       <subsection name="Description">

   373         <p>

   374           Determines complexity of methods, classes and files by

   375           counting the Non Commenting Source Statements (NCSS).  This

   376           check adheres to the <a

   377           href="http://www.kclee.de/clemens/java/javancss/#specification">

   378           specification</a> for the

   379           <a href="http://www.kclee.de/clemens/java/javancss/">JavaNCSS-Tool</a>

   380           written by <b>Chr. Clemens Lee</b>.<br/>

   381           Rougly said the NCSS metric is calculated by

   382           counting the source lines which are not comments, (nearly)

   383           equivalent to counting the semicolons and opening curly

   384           braces.<br/> The NCSS for a class is summarized from the NCSS

   385           of all its methods, the NCSS of its nested classes and the

   386           number of member variable declarations.<br/> The NCSS for a

   387           file is summarized from the ncss of all its top level classes,

   388           the number of imports and the package declaration.

   389         </p>

   391         <p>

   392           Rationale: Too large methods and classes are hard to read and

   393           costly to maintain. A large NCSS number often means that a

   394           method or class has too many responsabilities and/or

   395           functionalities which should be decomposed into smaller units.

   396         </p>

   397       </subsection>

   399       <subsection name="Properties">

   400         <table>

   401           <tr>

   402             <th>name</th>

   403             <th>description</th>

   404             <th>type</th>

   405             <th>default value</th>

   406           </tr>

   407           <tr>

   408             <td>methodMaximum</td>

   409             <td>

   410               the maximum allowed number of non commenting lines in a

   411               method.

   412             </td>

   413             <td><a href="property_types.html#integer">integer</a></td>

   414             <td><span class="default">50</span></td>

   415           </tr>

   416           <tr>

   417             <td>classMaximum</td>

   418             <td>

   419               the maximum allowed number of non commenting lines in a

   420               class.

   421             </td>

   422             <td><a href="property_types.html#integer">integer</a></td>

   423             <td><span class="default">1500</span></td>

   424           </tr>

   425           <tr>

   426             <td>fileMaximum</td>

   427             <td>

   428               the maximum allowed number of non commenting lines in a

   429               file including all top level and nested classes.

   430             </td>

   431             <td><a href="property_types.html#integer">integer</a></td>

   432             <td><span class="default">2000</span></td>

   433           </tr>

   434         </table>

   435       </subsection>

   437       <subsection name="Examples">

   438         <p>

   439           To configure the check:

   440         </p>

   441         <source>

   442 &lt;module name=&quot;JavaNCSS&quot;/&gt;

   443         </source>

   445         <p>

   446           To configure the check with 40 allowed non commenting lines

   447           for a method:

   448         </p>

   449         <source>

   450 &lt;module name=&quot;JavaNCSS&quot;&gt;

   451     &lt;property name=&quot;methodMaximum&quot; value=&quot;40&quot;/&gt;

   452 &lt;/module&gt;

   453         </source>

   454       </subsection>

   456       <subsection name="Package">

   457         <p>

   458           com.puppycrawl.tools.checkstyle.checks.metrics

   459         </p>

   460       </subsection>

   462       <subsection name="Parent Module">

   463         <p>

   464           <a href="config.html#treewalker">TreeWalker</a>

   465         </p>

   466       </subsection>

   467     </section>

   468   </body>

   469 </document>

author	oburn
	Mon Dec 22 22:31:40 2008 +0000 (2008-12-22)
changeset 2361	769708c5ee9f
parent 2197	742923956f44
child 2456	5dfe5afe6481
permissions	-rwxr-xr-x

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