public class JavaNCSSCheck extends AbstractCheck
Determines complexity of methods, classes and files by counting the Non Commenting Source Statements (NCSS). This check adheres to the specification for the JavaNCSS-Tool written by Chr. Clemens Lee.
Roughly said the NCSS metric is calculated by counting the source lines which are not comments, (nearly) equivalent to counting the semicolons and opening curly braces.
The NCSS for a class is summarized from the NCSS of all its methods, the NCSS of its nested classes and the number of member variable declarations.
The NCSS for a file is summarized from the ncss of all its top level classes, the number of imports and the package declaration.
Rationale: Too large methods and classes are hard to read and costly to maintain. A large NCSS number often means that a method or class has too many responsibilities and/or functionalities which should be decomposed into smaller units.
methodMaximum - Specify the maximum allowed number of
non commenting lines in a method.
Type is int.
Default value is 50.
classMaximum - Specify the maximum allowed number of
non commenting lines in a class.
Type is int.
Default value is 1500.
fileMaximum - Specify the maximum allowed number of
non commenting lines in a file including all top level and nested classes.
Type is int.
Default value is 2000.
To configure the check:
<module name="JavaNCSS"/>
Example:
public void test() {
System.out.println("Line 1");
// another 48 lines of code
System.out.println("Line 50") // OK
System.out.println("Line 51") // violation, the method crosses 50 non commented lines
}
To configure the check with 40 allowed non commented lines for a method:
<module name="JavaNCSS"> <property name="methodMaximum" value="40"/> </module>
Example:
public void test() {
System.out.println("Line 1");
// another 38 lines of code
System.out.println("Line 40") // OK
System.out.println("Line 41") // violation, the method crosses 40 non commented lines
}
To configure the check to set limit of non commented lines in class to 100:
<module name="JavaNCSS"> <property name="classMaximum" value="100"/> </module>
Example:
public class Test {
public void test() {
System.out.println("Line 1");
// another 47 lines of code
System.out.println("Line 49");
}
public void test1() {
System.out.println("Line 50"); // OK
// another 47 lines of code
System.out.println("Line 98"); // violation
}
}
To configure the check to set limit of non commented lines in file to 200:
<module name="JavaNCSS"> <property name="fileMaximum" value="200"/> </module>
Example:
public class Test1 {
public void test() {
System.out.println("Line 1");
// another 48 lines of code
System.out.println("Line 49");
}
public void test1() {
System.out.println("Line 50");
// another 47 lines of code
System.out.println("Line 98"); // OK
}
}
class Test2 {
public void test() {
System.out.println("Line 150"); // OK
}
public void test1() {
System.out.println("Line 200"); // violation
}
}
Parent is com.puppycrawl.tools.checkstyle.TreeWalker
Violation Message Keys:
ncss.class
ncss.file
ncss.method
AutomaticBean.OutputStreamOptions| Modifier and Type | Field and Description |
|---|---|
static String |
MSG_CLASS
A key is pointing to the warning message text in "messages.properties"
file.
|
static String |
MSG_FILE
A key is pointing to the warning message text in "messages.properties"
file.
|
static String |
MSG_METHOD
A key is pointing to the warning message text in "messages.properties"
file.
|
| Constructor and Description |
|---|
JavaNCSSCheck() |
| Modifier and Type | Method and Description |
|---|---|
void |
beginTree(DetailAST rootAST)
Called before the starting to process a tree.
|
void |
finishTree(DetailAST rootAST)
Called after finished processing a tree.
|
int[] |
getAcceptableTokens()
The configurable token set.
|
int[] |
getDefaultTokens()
Returns the default token a check is interested in.
|
int[] |
getRequiredTokens()
The tokens that this check must be registered for.
|
void |
leaveToken(DetailAST ast)
Called after all the child nodes have been process.
|
void |
setClassMaximum(int classMaximum)
Setter to specify the maximum allowed number of non commenting lines in a class.
|
void |
setFileMaximum(int fileMaximum)
Setter to specify the maximum allowed number of non commenting lines
in a file including all top level and nested classes.
|
void |
setMethodMaximum(int methodMaximum)
Setter to specify the maximum allowed number of non commenting lines in a method.
|
void |
visitToken(DetailAST ast)
Called to process a token.
|
clearMessages, destroy, getFileContents, getLine, getLines, getMessages, getTabWidth, getTokenNames, init, isCommentNodesRequired, log, log, log, setFileContents, setTabWidth, setTokensfinishLocalSetup, getCustomMessages, getId, getMessageBundle, getSeverity, getSeverityLevel, setId, setSeverityconfigure, contextualize, getConfiguration, setupChildpublic static final String MSG_METHOD
public static final String MSG_CLASS
public static final String MSG_FILE
public JavaNCSSCheck()
public int[] getDefaultTokens()
AbstractCheckgetDefaultTokens in class AbstractCheckTokenTypespublic int[] getRequiredTokens()
AbstractCheckgetRequiredTokens in class AbstractCheckTokenTypespublic int[] getAcceptableTokens()
AbstractCheckgetAcceptableTokens in class AbstractCheckTokenTypespublic void beginTree(DetailAST rootAST)
AbstractCheckbeginTree in class AbstractCheckrootAST - the root of the treepublic void visitToken(DetailAST ast)
AbstractCheckvisitToken in class AbstractCheckast - the token to processpublic void leaveToken(DetailAST ast)
AbstractCheckleaveToken in class AbstractCheckast - the token leavingpublic void finishTree(DetailAST rootAST)
AbstractCheckfinishTree in class AbstractCheckrootAST - the root of the treepublic void setFileMaximum(int fileMaximum)
fileMaximum - the maximum ncsspublic void setClassMaximum(int classMaximum)
classMaximum - the maximum ncsspublic void setMethodMaximum(int methodMaximum)
methodMaximum - the maximum ncssCopyright © 2001–2020. All rights reserved.