Class MissingSwitchDefaultCheck
- 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.MissingSwitchDefaultCheck
-
- All Implemented Interfaces:
Configurable
,Contextualizable
public class MissingSwitchDefaultCheck extends AbstractCheck
Checks that switch statement has adefault
clause.Rationale: It's usually a good idea to introduce a default case in every switch statement. Even if the developer is sure that all currently possible cases are covered, this should be expressed in the default branch, e.g. by using an assertion. This way the code is protected against later changes, e.g. introduction of new types in an enumeration type.
This check does not validate any switch expressions. Rationale: The compiler requires switch expressions to be exhaustive. This means that all possible inputs must be covered.
This check does not validate switch statements that use pattern or null labels. Rationale: Switch statements that use pattern or null labels are checked by the compiler for exhaustiveness. This means that all possible inputs must be covered.
See the Java Language Specification for more information about switch statements and expressions.
See the Java Language Specification for more information about patterns.
Parent is
com.puppycrawl.tools.checkstyle.TreeWalker
Violation Message Keys:
-
missing.switch.default
- Since:
- 3.1
-
-
Nested Class Summary
-
Nested classes/interfaces inherited from class com.puppycrawl.tools.checkstyle.AbstractAutomaticBean
AbstractAutomaticBean.OutputStreamOptions
-
-
Field Summary
Fields Modifier and Type Field Description static String
MSG_KEY
A key is pointing to the warning message text in "messages.properties" file.private static Set<Integer>
SWITCH_STATEMENT_PARENTS
Represents the possible parent tokens of a switch statement.
-
Constructor Summary
Constructors Constructor Description MissingSwitchDefaultCheck()
-
Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description private static boolean
containsDefaultCaseLabelElement(DetailAST detailAst)
Checks if a switch block contains a default case label.private static boolean
containsDefaultLabel(DetailAST detailAst)
Checks if the case group or its sibling contain the 'default' switch.private static boolean
containsNullCaseLabelElement(DetailAST detailAst)
Checks if a switch block contains a null case label.private static boolean
containsPatternCaseLabelElement(DetailAST detailAst)
Checks if a switch block contains a case label with a pattern variable definition or record pattern definition.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.private static boolean
hasNullCaseLabel(DetailAST detailAST)
Checks if the case contains null label.private static boolean
isSwitchExpression(DetailAST ast)
Checks if this LITERAL_SWITCH token is part of a switch expression.void
visitToken(DetailAST ast)
Called to process a token.-
Methods inherited from class com.puppycrawl.tools.checkstyle.api.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 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
-
-
-
-
Field Detail
-
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
-
SWITCH_STATEMENT_PARENTS
private static final Set<Integer> SWITCH_STATEMENT_PARENTS
Represents the possible parent tokens of a switch statement.
-
-
Constructor Detail
-
MissingSwitchDefaultCheck
public MissingSwitchDefaultCheck()
-
-
Method Detail
-
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 classAbstractCheck
- 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 classAbstractCheck
- 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 classAbstractCheck
- 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 classAbstractCheck
- Parameters:
ast
- the token to process
-
containsDefaultLabel
private static boolean containsDefaultLabel(DetailAST detailAst)
Checks if the case group or its sibling contain the 'default' switch.- Parameters:
detailAst
- first case group to check.- Returns:
- true if 'default' switch found.
-
containsPatternCaseLabelElement
private static boolean containsPatternCaseLabelElement(DetailAST detailAst)
Checks if a switch block contains a case label with a pattern variable definition or record pattern definition. In this situation, the compiler enforces the given switch block to cover all possible inputs, and we do not need a default label.- Parameters:
detailAst
- first case group to check.- Returns:
- true if switch block contains a pattern case label element
-
containsDefaultCaseLabelElement
private static boolean containsDefaultCaseLabelElement(DetailAST detailAst)
Checks if a switch block contains a default case label.- Parameters:
detailAst
- first case group to check.- Returns:
- true if switch block contains default case label
-
containsNullCaseLabelElement
private static boolean containsNullCaseLabelElement(DetailAST detailAst)
Checks if a switch block contains a null case label.- Parameters:
detailAst
- first case group to check.- Returns:
- true if switch block contains null case label
-
isSwitchExpression
private static boolean isSwitchExpression(DetailAST ast)
Checks if this LITERAL_SWITCH token is part of a switch expression.- Parameters:
ast
- the switch statement we are checking- Returns:
- true if part of a switch expression
-
hasNullCaseLabel
private static boolean hasNullCaseLabel(DetailAST detailAST)
Checks if the case contains null label.- Parameters:
detailAST
- the switch statement we are checking- Returns:
- returnValue the ast of null label
-
-