public final class ClassFanOutComplexityCheck extends AbstractClassCouplingCheck
Checks the number of other classes a given class relies on. Also the square of this has been shown to indicate the amount of maintenance required in functional programs (on a file basis) at least.
This check processes files in the following way:
import java.math.BigDecimal),
or the class was referenced with the package name (i.e. java.math.BigDecimal value)
and the package was added to the excludedPackages parameter,
the class does not increase complexity.
excludedClasses parameter,
the class does not increase complexity.
max - Specify the maximum threshold allowed.
Type is int.
Default value is 20.
excludedClasses - Specify user-configured class names to ignore.
Type is java.lang.String[].
Default value is ArrayIndexOutOfBoundsException, ArrayList, Boolean, Byte,
Character, Class, Deprecated, Deque, Double, Exception, Float, FunctionalInterface,
HashMap, HashSet, IllegalArgumentException, IllegalStateException,
IndexOutOfBoundsException, Integer, LinkedList, List, Long, Map, NullPointerException,
Object, Override, Queue, RuntimeException, SafeVarargs, SecurityException, Set, Short,
SortedMap, SortedSet, String, StringBuffer, StringBuilder, SuppressWarnings, Throwable,
TreeMap, TreeSet, UnsupportedOperationException, Void, boolean, byte, char, double,
float, int, long, short, void.
excludeClassesRegexps - Specify user-configured regular
expressions to ignore classes.
Type is java.lang.String[].
Default value is ^$.
excludedPackages - Specify user-configured packages to ignore.
All excluded packages should end with a period, so it also appends a dot to a package name.
Type is java.lang.String[].
Default value is {}.
To configure the check:
<module name="ClassFanOutComplexity"/>
Example:
The check passes without violations in the following:
class InputClassComplexity {
Set set = new HashSet(); // Set, HashSet ignored due to default excludedClasses property
Map map = new HashMap(); // Map, HashMap ignored due to default excludedClasses property
Date date = new Date(); // Counted, 1
Time time = new Time(); // Counted, 2
Place place = new Place(); // Counted, 3
}
The check results in a violation in the following:
class InputClassComplexity {
Set set = new HashSet(); // Set, HashSet ignored due to default excludedClasses property
Map map = new HashMap(); // Map, HashMap ignored due to default excludedClasses property
Date date = new Date(); // Counted, 1
Time time = new Time(); // Counted, 2
// mention of 18 other user defined classes
Place place = new Place(); // violation, total is 21
}
To configure the check with a threshold of 2:
<module name="ClassFanOutComplexity"> <property name="max" value="2"/> </module>
Example:
The check passes without violations in the following:
class InputClassComplexity {
Set set = new HashSet(); // Set, HashSet ignored due to default excludedClasses property
Map map = new HashMap(); // Map, HashMap ignored due to default excludedClasses property
Date date = new Date(); // Counted, 1
Time time = new Time(); // Counted, 2
}
The check results in a violation in the following:
class InputClassComplexity {
Set set = new HashSet(); // Set, HashSet ignored due to default excludedClasses property
Map map = new HashMap(); // Map, HashMap ignored due to default excludedClasses property
Date date = new Date(); // Counted, 1
Time time = new Time(); // Counted, 2
Place place = new Place(); // violation, total is 3
}
To configure the check with three excluded classes HashMap,
HashSet and Place:
<module name="ClassFanOutComplexity"> <property name="excludedClasses" value="HashMap, HashSet, Place"/> </module>
Example:
The check passes without violations in the following:
class InputClassComplexity {
Set set = new HashSet(); // Set counted 1, HashSet ignored
Map map = new HashMap(); // Map counted 2, HashMap ignored
Date date = new Date(); // Counted, 3
Time time = new Time(); // Counted, 4
// mention of 16 other user defined classes
Place place = new Place(); // Ignored
}
The check results in a violation in the following:
class InputClassComplexity {
Set set = new HashSet(); // Set counted 1, HashSet ignored
Map map = new HashMap(); // Map counted 2, HashMap ignored
Date date = new Date(); // Counted, 3
Time time = new Time(); // Counted, 4
// mention of 16 other user defined classes
Space space = new Space(); // violation, total is 21
}
To configure the check to exclude classes with a regular expression
.*Reader$:
<module name="ClassFanOutComplexity"> <property name="excludeClassesRegexps" value=".*Reader$"/> </module>
Example:
The check passes without violations in the following:
class InputClassComplexity {
Set set = new HashSet(); // Set, HashSet ignored due to default excludedClasses property
Map map = new HashMap(); // Map, HashMap ignored due to default excludedClasses property
Date date = new Date(); // Counted, 1
Time time = new Time(); // Counted, 2
// mention of 18 other user defined classes
BufferedReader br; // Ignored
}
The check results in a violation in the following:
class InputClassComplexity {
Set set = new HashSet(); // Set, HashSet ignored due to default excludedClasses property
Map map = new HashMap(); // Map, HashMap ignored due to default excludedClasses property
Date date = new Date(); // Counted, 1
Time time = new Time(); // Counted, 2
// mention of 18 other user defined classes
File file; // violation, total is 21
}
To configure the check with an excluded package java.io:
<module name="ClassFanOutComplexity"> <property name="excludedPackages" value="java.io"/> </module>
Example:
The check passes without violations in the following:
import java.io.BufferedReader;
class InputClassComplexity {
Set set = new HashSet(); // Set, HashSet ignored due to default excludedClasses property
Map map = new HashMap(); // Map, HashMap ignored due to default excludedClasses property
Date date = new Date(); // Counted, 1
Time time = new Time(); // Counted, 2
// mention of 18 other user defined classes
BufferedReader br; // Ignored
}
The check results in a violation in the following:
import java.util.StringTokenizer;
class InputClassComplexity {
Set set = new HashSet(); // Set, HashSet ignored due to default excludedClasses property
Map map = new HashMap(); // Map, HashMap ignored due to default excludedClasses property
Date date = new Date(); // Counted, 1
Time time = new Time(); // Counted, 2
// mention of 18 other user defined classes
StringTokenizer st; // violation, total is 21
}
Override property excludedPackages to mark some packages as excluded.
Each member of excludedPackages should be a valid identifier:
java.util - valid, excludes all classes inside java.util,
but not from the subpackages.
java.util. - invalid, should not end with a dot.
java.util.* - invalid, should not end with a star.
Note, that checkstyle will ignore all classes from the java.lang
package and its subpackages, even if the java.lang was not listed
in the excludedPackages parameter.
Also note, that excludedPackages will not exclude classes, imported
via wildcard (e.g. import java.math.*). Instead of wildcard import
you should use direct import (e.g. import java.math.BigDecimal).
Also note, that checkstyle will not exclude classes within the same file even
if it was listed in the excludedPackages parameter.
For example, assuming the config is
<module name="ClassFanOutComplexity"> <property name="excludedPackages" value="a.b"/> </module>
And the file a.b.Foo.java is:
package a.b;
import a.b.Bar;
import a.b.c.Baz;
class Foo {
Bar bar; // Will be ignored, located inside ignored a.b package
Baz baz; // Will not be ignored, located inside a.b.c package
Data data; // Will not be ignored, same file
class Data {
Foo foo; // Will not be ignored, same file
}
}
The bar member will not be counted, since the a.b
added to the excludedPackages. The baz member will be counted,
since the a.b.c was not added to the excludedPackages.
The data and foo members will be counted, as they are inside same file.
Parent is com.puppycrawl.tools.checkstyle.TreeWalker
Violation Message Keys:
classFanOutComplexity
AutomaticBean.OutputStreamOptions| Modifier and Type | Field and Description |
|---|---|
static String |
MSG_KEY
A key is pointing to the warning message text in "messages.properties"
file.
|
| Constructor and Description |
|---|
ClassFanOutComplexityCheck()
Creates new instance of this check.
|
| Modifier and Type | Method and Description |
|---|---|
int[] |
getAcceptableTokens()
The configurable token set.
|
protected String |
getLogMessageId()
Returns message key we use for log violations.
|
int[] |
getRequiredTokens()
The tokens that this check must be registered for.
|
beginTree, getDefaultTokens, leaveToken, setExcludeClassesRegexps, setExcludedClasses, setExcludedPackages, setMax, visitTokenclearMessages, destroy, finishTree, 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_KEY
public ClassFanOutComplexityCheck()
public int[] getRequiredTokens()
AbstractCheckgetRequiredTokens in class AbstractCheckTokenTypespublic int[] getAcceptableTokens()
AbstractCheckgetAcceptableTokens in class AbstractCheckTokenTypesprotected String getLogMessageId()
AbstractClassCouplingCheckgetLogMessageId in class AbstractClassCouplingCheckCopyright © 2001–2020. All rights reserved.