phoedos/pmd
1
1
Fork 1
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

tweak

Browse Source 
git-svn-id: https://pmd.svn.sourceforge.net/svnroot/pmd/trunk@527 51baf565-9d33-0410-a72c-fc3788e3496d
This commit is contained in:
Tom Copeland
2002-07-26 16:37:17 +00:00
parent fbaf1103a1
commit e8b339974f
1 changed files with 28 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

30
pmd/xdocs/howtowritearule.xml
View File

@ -126,14 +126,40 @@ WhileStatement
</source>
<p>
Ah ha! We see that the curly braces add a couple more AST elements - a Block and a BlockStatement. So all we have
to do is write a rule to detect a WhileStatement that's not followed by a Block, and we've got it.
to do is write a rule to detect a WhileStatement that has a Statement that's not followed by a Block, and we've got a rule violation.
</p>
</subsection>
<subsection name="Write a rule class">
<p>
Create a new Java class that extends <code>net.sourceforge.pmd.AbstractRule</code>:
</p>
<source>
<![CDATA[
public class WhileLoopsMustUseBracesRule extends BracesRule {
}
]]>
</source>
<p>
That was easy. PMD works by creating the AST and then traverses it recursively so a rule can get a callback
for any type it's interested in. So let's make sure our rule gets called whenever the AST traversal finds a WhileStatement:
</p>
<source>
<![CDATA[
public class WhileLoopsMustUseBracesRule extends BracesRule {
public Object visit(ASTWhileStatement node, Object data) {
System.out.println("hello world");
}
}
]]>
</source>
<p>
We stuck a <code>println()</code> in there for now so we can see when our rule gets hit.
</p>
</subsection>
<subsection name="Put the EmptyWhileLoop rule in a ruleset file">
<subsection name="Put the WhileLoopsMustUseBracesRule rule in a ruleset file">
</subsection>
<subsection name="Run PMD using your new ruleset">