Package com.puppycrawl.tools.checkstyle.checks.metrics

Class ClassFanOutComplexityCheck

java.lang.Object

com.puppycrawl.tools.checkstyle.AbstractAutomaticBean

com.puppycrawl.tools.checkstyle.api.AbstractViolationReporter

com.puppycrawl.tools.checkstyle.api.AbstractCheck

com.puppycrawl.tools.checkstyle.checks.metrics.AbstractClassCouplingCheck

com.puppycrawl.tools.checkstyle.checks.metrics.ClassFanOutComplexityCheck

All Implemented Interfaces:

Configurable, Contextualizable

public final class ClassFanOutComplexityCheck
extends AbstractClassCouplingCheck

Checks the number of other types a given class/record/interface/enum/annotation 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:

1. Iterates over all tokens that might contain type reference.
2. If a class was imported with direct import (i.e. 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.
3. If a class name was added to the excludedClasses parameter, the class does not increase complexity.

• Property excludeClassesRegexps - Specify user-configured regular expressions to ignore classes. Type is java.util.regex.Pattern[]. Default value is ^$.
• Property excludedClasses - Specify user-configured class names to ignore. Type is java.lang.String[]. Default value is ArrayIndexOutOfBoundsException, ArrayList, Boolean, Byte, Character, Class, Collection, Deprecated, Deque, Double, DoubleStream, EnumSet, Exception, Float, FunctionalInterface, HashMap, HashSet, IllegalArgumentException, IllegalStateException, IndexOutOfBoundsException, IntStream, Integer, LinkedHashMap, LinkedHashSet, LinkedList, List, Long, LongStream, Map, NullPointerException, Object, Optional, OptionalDouble, OptionalInt, OptionalLong, Override, Queue, RuntimeException, SafeVarargs, SecurityException, Set, Short, SortedMap, SortedSet, Stream, String, StringBuffer, StringBuilder, SuppressWarnings, Throwable, TreeMap, TreeSet, UnsupportedOperationException, Void, boolean, byte, char, double, float, int, long, short, var, void.
• Property excludedPackages - Specify user-configured packages to ignore. Type is java.lang.String[]. Default value is "".
• Property max - Specify the maximum threshold allowed. Type is int. Default value is 20.

Parent is com.puppycrawl.tools.checkstyle.TreeWalker

Violation Message Keys:

• classFanOutComplexity

Since:

3.4

Nested Class Summary

Nested classes/interfaces inherited from class com.puppycrawl.tools.checkstyle.AbstractAutomaticBean

AbstractAutomaticBean.OutputStreamOptions

Field Summary

Fields

Modifier and Type	Field	Description
private static final int	DEFAULT_MAX	Default value of max value.
static final String	MSG_KEY	A key is pointing to the warning message text in "messages.properties" file.

Constructor Summary

Constructors

Constructor	Description
ClassFanOutComplexityCheck()	Creates new instance of this check.

Method Summary

Modifier and Type	Method	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.

Methods inherited from class com.puppycrawl.tools.checkstyle.checks.metrics.AbstractClassCouplingCheck

beginTree, getDefaultTokens, leaveToken, setExcludeClassesRegexps, setExcludedClasses, setExcludedPackages, setMax, visitToken

Methods inherited from class com.puppycrawl.tools.checkstyle.api.AbstractCheck

clearViolations, destroy, finishTree, getFileContents, getFilePath, getLine, getLineCodePoints, getLines, getTabWidth, getTokenNames, getViolations, init, isCommentNodesRequired, log, log, log, setFileContents, setTabWidth, setTokens

Methods inherited from class com.puppycrawl.tools.checkstyle.api.AbstractViolationReporter

finishLocalSetup, getCustomMessages, getId, getMessageBundle, getSeverity, getSeverityLevel, setId, setSeverity

Methods inherited from class com.puppycrawl.tools.checkstyle.AbstractAutomaticBean

configure, contextualize, getConfiguration, setupChild

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

MSG_KEY

public static final String MSG_KEY

A key is pointing to the warning message text in "messages.properties" file.

See Also:

• Constant Field Values

DEFAULT_MAX

private static final int DEFAULT_MAX

Default value of max value.

See Also:

• Constant Field Values

Constructor Details

ClassFanOutComplexityCheck

public ClassFanOutComplexityCheck()

Creates new instance of this check.

Method Details

getRequiredTokens

public int[] getRequiredTokens()

Description copied from class: AbstractCheck

The tokens that this check must be registered for.

Specified by:

getRequiredTokens in class AbstractCheck

Returns:

the token set this must be registered for.

See Also:

• TokenTypes

getAcceptableTokens

public int[] getAcceptableTokens()

Description copied from class: AbstractCheck

The configurable token set. Used to protect Checks against malicious users who specify an unacceptable token set in the configuration file. The default implementation returns the check's default tokens.

Specified by:

getAcceptableTokens in class AbstractCheck

Returns:

the token set this check is designed for.

See Also:

• TokenTypes

getLogMessageId

protected String getLogMessageId()

Description copied from class: AbstractClassCouplingCheck

Returns message key we use for log violations.

Specified by:

getLogMessageId in class AbstractClassCouplingCheck

Returns:

message key we use for log violations.