Class UnnecessaryParenthesesCheck
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.coding.UnnecessaryParenthesesCheck
- All Implemented Interfaces:
Configurable
,Contextualizable
Checks if unnecessary parentheses are used in a statement or expression. The check will flag the following with warnings:
return (x); // parens around identifier return (x + 1); // parens around return value int x = (y / 2 + 1); // parens around assignment rhs for (int i = (0); i < 10; i++) { // parens around literal t -= (z + 1); // parens around assignment rhs
The check is not "type aware", that is to say, it can't tell if parentheses are unnecessary based on the types in an expression. It also doesn't know about operator precedence and associativity; therefore it won't catch something like
int x = (a + b) + c;
In the above case, given that a, b, and c are
all int
variables, the parentheses around a + b
are not needed.
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Property
tokens
- tokens to check Type isjava.lang.String[]
. Validation type istokenSet
. Default value is: EXPR, IDENT, NUM_DOUBLE, NUM_FLOAT, NUM_INT, NUM_LONG, STRING_LITERAL, LITERAL_NULL, LITERAL_FALSE, LITERAL_TRUE, ASSIGN, BAND_ASSIGN, BOR_ASSIGN, BSR_ASSIGN, BXOR_ASSIGN, DIV_ASSIGN, MINUS_ASSIGN, MOD_ASSIGN, PLUS_ASSIGN, SL_ASSIGN, SR_ASSIGN, STAR_ASSIGN, LAMBDA, TEXT_BLOCK_LITERAL_BEGIN.
To configure the check:
<module name="UnnecessaryParentheses"/>
Which results in the following violations:
public int square(int a, int b){ int square = (a * b); //violation return (square); //violation } int sumOfSquares = 0; for(int i=(0); i<10; i++){ //violation int x = (i + 1); //violation sumOfSquares += (square(x * x)); //violation } double num = (10.0); //violation List<String> list = Arrays.asList("a1", "b1", "c1"); myList.stream() .filter((s) -> s.startsWith("c")) //violation .forEach(System.out::println);
Parent is com.puppycrawl.tools.checkstyle.TreeWalker
Violation Message Keys:
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unnecessary.paren.assign
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unnecessary.paren.expr
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unnecessary.paren.ident
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unnecessary.paren.lambda
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unnecessary.paren.literal
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unnecessary.paren.return
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unnecessary.paren.string
- Since:
- 3.4
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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.static final String
A key is pointing to the warning message text in "messages.properties" file.static final String
A key is pointing to the warning message text in "messages.properties" file.static final String
A key is pointing to the warning message text in "messages.properties" file.static final String
A key is pointing to the warning message text in "messages.properties" file.static final String
A key is pointing to the warning message text in "messages.properties" file.static 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
leaveToken
(DetailAST ast) Called after all the child nodes have been process.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, 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_IDENT
A key is pointing to the warning message text in "messages.properties" file.- See Also:
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MSG_ASSIGN
A key is pointing to the warning message text in "messages.properties" file.- See Also:
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MSG_EXPR
A key is pointing to the warning message text in "messages.properties" file.- See Also:
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MSG_LITERAL
A key is pointing to the warning message text in "messages.properties" file.- See Also:
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MSG_STRING
A key is pointing to the warning message text in "messages.properties" file.- See Also:
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MSG_RETURN
A key is pointing to the warning message text in "messages.properties" file.- See Also:
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MSG_LAMBDA
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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UnnecessaryParenthesesCheck
public UnnecessaryParenthesesCheck()
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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:
-
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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leaveToken
Description copied from class:AbstractCheck
Called after all the child nodes have been process.- Overrides:
leaveToken
in classAbstractCheck
- Parameters:
ast
- the token leaving
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