Class AvoidNestedBlocksCheck
java.lang.Object
com.puppycrawl.tools.checkstyle.api.AutomaticBean
com.puppycrawl.tools.checkstyle.api.AbstractViolationReporter
com.puppycrawl.tools.checkstyle.api.AbstractCheck
com.puppycrawl.tools.checkstyle.checks.blocks.AvoidNestedBlocksCheck
- All Implemented Interfaces:
Configurable
,Contextualizable
Finds nested blocks (blocks that are used freely in the code).
Rationale: Nested blocks are often leftovers from the debugging process, they confuse the reader.
For example this Check finds the obsolete braces in
public void guessTheOutput() { int whichIsWhich = 0; { whichIsWhich = 2; } System.out.println("value = " + whichIsWhich); }
and debugging / refactoring leftovers such as
// if (conditionThatIsNotUsedAnyLonger) { System.out.println("unconditional"); }
A case in a switch statement does not implicitly form a block. Thus to be able to introduce local variables that have case scope it is necessary to open a nested block. This is supported, set the allowInSwitchCase property to true and include all statements of the case in the block.
switch (a) { case 0: // Never OK, break outside block { x = 1; } break; case 1: // Never OK, statement outside block System.out.println("Hello"); { x = 2; break; } case 2: // OK if allowInSwitchCase is true { System.out.println("Hello"); x = 3; break; } }
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Property
allowInSwitchCase
- Allow nested blocks if they are the only child of a switch case. Type isboolean
. Default value isfalse
.
To configure the check:
<module name="AvoidNestedBlocks"/>
Parent is com.puppycrawl.tools.checkstyle.TreeWalker
Violation Message Keys:
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block.nested
- Since:
- 3.1
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Nested Class Summary
Nested classes/interfaces inherited from class com.puppycrawl.tools.checkstyle.api.AutomaticBean
AutomaticBean.OutputStreamOptions
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Field Summary
FieldsModifier and TypeFieldDescriptionstatic final String
A key is pointing to the warning message text in "messages.properties" file. -
Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionint[]
The configurable token set.int[]
Returns the default token a check is interested in.int[]
The tokens that this check must be registered for.void
setAllowInSwitchCase
(boolean allowInSwitchCase) Setter to allow nested blocks if they are the only child of a switch case.void
visitToken
(DetailAST ast) Called to process a token.Methods inherited from class com.puppycrawl.tools.checkstyle.api.AbstractCheck
beginTree, clearMessages, destroy, finishTree, getFileContents, getLine, getLines, getMessages, getTabWidth, getTokenNames, 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.api.AutomaticBean
configure, contextualize, getConfiguration, setupChild
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Field Details
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MSG_KEY_BLOCK_NESTED
A key is pointing to the warning message text in "messages.properties" file.- See Also:
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Constructor Details
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AvoidNestedBlocksCheck
public AvoidNestedBlocksCheck()
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Method Details
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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:
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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:
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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:
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visitToken
Description copied from class:AbstractCheck
Called to process a token.- Overrides:
visitToken
in classAbstractCheck
- Parameters:
ast
- the token to process
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setAllowInSwitchCase
public void setAllowInSwitchCase(boolean allowInSwitchCase) Setter to allow nested blocks if they are the only child of a switch case.- Parameters:
allowInSwitchCase
- whether nested blocks are allowed if they are the only child of a switch case.
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