Class UseEnhancedSwitchCheck

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.coding.UseEnhancedSwitchCheck

All Implemented Interfaces:

Configurable, Contextualizable

public class UseEnhancedSwitchCheck
extends AbstractCheck

Ensures that the enhanced switch (using -> for case labels) is used instead of the traditional switch (using : for case labels) where possible.

Rationale: Java 14 has introduced enhancements for switch statements and expressions that disallow fall-through behavior. The enhanced switch syntax using -> for case labels typically leads to more concise and readable code, reducing the likelihood of errors associated with fall-through cases.

See the Java Language Specification for more information about -> case labels, also known as "switch rules".

Since:

13.3.0

Nested Class Summary

Nested classes/interfaces inherited from class AbstractAutomaticBean

AbstractAutomaticBean.OutputStreamOptions

Field Summary

Fields

Modifier and Type	Field	Description
static final String	MSG_KEY	A key is pointing to the warning message text in "messages.properties" file.

Constructor Summary

Constructors

Constructor	Description
UseEnhancedSwitchCheck()

Method Summary

Modifier and Type	Method	Description
private static boolean	allCaseGroupsTerminate(List<DetailAST> caseGroups)	Check if all case groups terminate (i.e.
int[]	getAcceptableTokens()	The configurable token set.
private static List<DetailAST>	getCaseGroups(DetailAST switchAst)	Get all case groups from the switch.
int[]	getDefaultTokens()	Returns the default token a check is interested in.
int[]	getRequiredTokens()	The tokens that this check must be registered for.
void	visitToken(DetailAST ast)	Called to process a token.

Methods inherited from class AbstractCheck

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

Methods inherited from class AbstractViolationReporter

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

Methods inherited from class AbstractAutomaticBean

configure, contextualize, getConfiguration, setupChild

Methods inherited from class 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

Constructor Details

UseEnhancedSwitchCheck

public UseEnhancedSwitchCheck()

Method Details

getDefaultTokens

public int[] getDefaultTokens()

Description copied from class: AbstractCheck

Returns the default token a check is interested in. Only used if the configuration for a check does not define the tokens.

Specified by:

getDefaultTokens in class AbstractCheck

Returns:

the default tokens

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

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

visitToken

public void visitToken(DetailAST ast)

Description copied from class: AbstractCheck

Called to process a token.

Overrides:

visitToken in class AbstractCheck

Parameters:

ast - the token to process

allCaseGroupsTerminate

private static boolean allCaseGroupsTerminate(List<DetailAST> caseGroups)

Check if all case groups terminate (i.e. do not fall through), except the last one which terminates regardless of its content.

Parameters:

caseGroups - the list of case groups to check

Returns:

true if all case groups terminate, false otherwise

getCaseGroups

private static List<DetailAST> getCaseGroups(DetailAST switchAst)

Get all case groups from the switch.

Parameters:

switchAst - the AST node representing a LITERAL_SWITCH

Returns:

all CASE_GROUP nodes within the switch