Class MagicNumberCheck
- java.lang.Object
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- com.puppycrawl.tools.checkstyle.AbstractAutomaticBean
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- com.puppycrawl.tools.checkstyle.api.AbstractViolationReporter
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- com.puppycrawl.tools.checkstyle.api.AbstractCheck
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- com.puppycrawl.tools.checkstyle.checks.coding.MagicNumberCheck
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- All Implemented Interfaces:
Configurable
,Contextualizable
public class MagicNumberCheck extends AbstractCheck
Checks that there are no "magic numbers" where a magic number is a numeric literal that is not defined as a constant. By default, -1, 0, 1, and 2 are not considered to be magic numbers.Constant definition is any variable/field that has 'final' modifier. It is fine to have one constant defining multiple numeric literals within one expression:
static final int SECONDS_PER_DAY = 24 * 60 * 60; static final double SPECIAL_RATIO = 4.0 / 3.0; static final double SPECIAL_SUM = 1 + Math.E; static final double SPECIAL_DIFFERENCE = 4 - Math.PI; static final Border STANDARD_BORDER = BorderFactory.createEmptyBorder(3, 3, 3, 3); static final Integer ANSWER_TO_THE_ULTIMATE_QUESTION_OF_LIFE = new Integer(42);
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Property
constantWaiverParentToken
- Specify tokens that are allowed in the AST path from the number literal to the enclosing constant definition. Type isjava.lang.String[]
. Validation type istokenTypesSet
. Default value is ARRAY_INIT, ASSIGN, DIV, ELIST, EXPR, LITERAL_NEW, METHOD_CALL, MINUS, PLUS, STAR, TYPECAST, UNARY_MINUS, UNARY_PLUS. -
Property
ignoreAnnotation
- Ignore magic numbers in annotation declarations. Type isboolean
. Default value isfalse
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Property
ignoreAnnotationElementDefaults
- Ignore magic numbers in annotation elements defaults. Type isboolean
. Default value istrue
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Property
ignoreFieldDeclaration
- Ignore magic numbers in field declarations. Type isboolean
. Default value isfalse
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Property
ignoreHashCodeMethod
- Ignore magic numbers in hashCode methods. Type isboolean
. Default value isfalse
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Property
ignoreNumbers
- Specify non-magic numbers. Type isdouble[]
. Default value is-1, 0, 1, 2
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Property
tokens
- tokens to check Type isjava.lang.String[]
. Validation type istokenSet
. Default value is: NUM_DOUBLE, NUM_FLOAT, NUM_INT, NUM_LONG.
Parent is
com.puppycrawl.tools.checkstyle.TreeWalker
Violation Message Keys:
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magic.number
- Since:
- 3.1
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Nested Class Summary
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Nested classes/interfaces inherited from class com.puppycrawl.tools.checkstyle.AbstractAutomaticBean
AbstractAutomaticBean.OutputStreamOptions
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Field Summary
Fields Modifier and Type Field Description private BitSet
constantWaiverParentToken
Specify tokens that are allowed in the AST path from the number literal to the enclosing constant definition.private boolean
ignoreAnnotation
Ignore magic numbers in annotation declarations.private boolean
ignoreAnnotationElementDefaults
Ignore magic numbers in annotation elements defaults.private boolean
ignoreFieldDeclaration
Ignore magic numbers in field declarations.private boolean
ignoreHashCodeMethod
Ignore magic numbers in hashCode methods.private double[]
ignoreNumbers
Specify non-magic numbers.static String
MSG_KEY
A key is pointing to the warning message text in "messages.properties" file.
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Constructor Summary
Constructors Constructor Description MagicNumberCheck()
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description private static DetailAST
findContainingConstantDef(DetailAST ast)
Finds the constant definition that contains aAST.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
isChildOf(DetailAST ast, int type)
Determines if the given AST node has a parent node with given token type code.private static boolean
isFieldDeclaration(DetailAST ast)
Determines whether or not the given AST is field declaration.private static boolean
isInHashCodeMethod(DetailAST ast)
Determines whether or not the given AST is in a valid hash code method.private boolean
isInIgnoreList(DetailAST ast)
Decides whether the number of an AST is in the ignore list of this check.private boolean
isMagicNumberExists(DetailAST ast, DetailAST constantDefAST)
Is magic number somewhere at ast tree.private void
reportMagicNumber(DetailAST ast)
Reports aAST as a magic number, includes unary operators as needed.void
setConstantWaiverParentToken(String... tokens)
Setter to specify tokens that are allowed in the AST path from the number literal to the enclosing constant definition.void
setIgnoreAnnotation(boolean ignoreAnnotation)
Setter to ignore magic numbers in annotation declarations.void
setIgnoreAnnotationElementDefaults(boolean ignoreAnnotationElementDefaults)
Setter to ignore magic numbers in annotation elements defaults.void
setIgnoreFieldDeclaration(boolean ignoreFieldDeclaration)
Setter to ignore magic numbers in field declarations.void
setIgnoreHashCodeMethod(boolean ignoreHashCodeMethod)
Setter to ignore magic numbers in hashCode methods.void
setIgnoreNumbers(double... list)
Setter to specify non-magic numbers.private boolean
shouldTestAnnotationArgs(DetailAST ast)
Checks if ast is annotation argument and should be checked.private boolean
shouldTestAnnotationDefaults(DetailAST ast)
Checks if ast is annotation element default value and should be checked.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
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Methods inherited from class com.puppycrawl.tools.checkstyle.api.AbstractViolationReporter
finishLocalSetup, getCustomMessages, getId, getMessageBundle, getSeverity, getSeverityLevel, setId, setSeverity
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Methods inherited from class com.puppycrawl.tools.checkstyle.AbstractAutomaticBean
configure, contextualize, getConfiguration, setupChild
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Field Detail
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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
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constantWaiverParentToken
private BitSet constantWaiverParentToken
Specify tokens that are allowed in the AST path from the number literal to the enclosing constant definition.
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ignoreNumbers
private double[] ignoreNumbers
Specify non-magic numbers.
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ignoreHashCodeMethod
private boolean ignoreHashCodeMethod
Ignore magic numbers in hashCode methods.
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ignoreAnnotation
private boolean ignoreAnnotation
Ignore magic numbers in annotation declarations.
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ignoreFieldDeclaration
private boolean ignoreFieldDeclaration
Ignore magic numbers in field declarations.
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ignoreAnnotationElementDefaults
private boolean ignoreAnnotationElementDefaults
Ignore magic numbers in annotation elements defaults.
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Constructor Detail
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MagicNumberCheck
public MagicNumberCheck()
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Method Detail
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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:
TokenTypes
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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:
TokenTypes
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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:
TokenTypes
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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
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shouldTestAnnotationArgs
private boolean shouldTestAnnotationArgs(DetailAST ast)
Checks if ast is annotation argument and should be checked.- Parameters:
ast
- token to check- Returns:
- true if element is skipped, false otherwise
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shouldTestAnnotationDefaults
private boolean shouldTestAnnotationDefaults(DetailAST ast)
Checks if ast is annotation element default value and should be checked.- Parameters:
ast
- token to check- Returns:
- true if element is skipped, false otherwise
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isMagicNumberExists
private boolean isMagicNumberExists(DetailAST ast, DetailAST constantDefAST)
Is magic number somewhere at ast tree.- Parameters:
ast
- ast tokenconstantDefAST
- constant ast- Returns:
- true if magic number is present
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findContainingConstantDef
private static DetailAST findContainingConstantDef(DetailAST ast)
Finds the constant definition that contains aAST.- Parameters:
ast
- the AST- Returns:
- the constant def or null if ast is not contained in a constant definition.
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reportMagicNumber
private void reportMagicNumber(DetailAST ast)
Reports aAST as a magic number, includes unary operators as needed.- Parameters:
ast
- the AST node that contains the number to report
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isInHashCodeMethod
private static boolean isInHashCodeMethod(DetailAST ast)
Determines whether or not the given AST is in a valid hash code method. A valid hash code method is considered to be a method of the signaturepublic int hashCode()
.- Parameters:
ast
- the AST from which to search for an enclosing hash code method definition- Returns:
true
ifast
is in the scope of a valid hash code method.
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isInIgnoreList
private boolean isInIgnoreList(DetailAST ast)
Decides whether the number of an AST is in the ignore list of this check.- Parameters:
ast
- the AST to check- Returns:
- true if the number of ast is in the ignore list of this check.
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isFieldDeclaration
private static boolean isFieldDeclaration(DetailAST ast)
Determines whether or not the given AST is field declaration.- Parameters:
ast
- AST from which to search for an enclosing field declaration- Returns:
true
ifast
is in the scope of field declaration
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setConstantWaiverParentToken
public void setConstantWaiverParentToken(String... tokens)
Setter to specify tokens that are allowed in the AST path from the number literal to the enclosing constant definition.- Parameters:
tokens
- The string representation of the tokens interested in- Since:
- 6.11
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setIgnoreNumbers
public void setIgnoreNumbers(double... list)
Setter to specify non-magic numbers.- Parameters:
list
- numbers to ignore.- Since:
- 3.1
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setIgnoreHashCodeMethod
public void setIgnoreHashCodeMethod(boolean ignoreHashCodeMethod)
Setter to ignore magic numbers in hashCode methods.- Parameters:
ignoreHashCodeMethod
- decide whether to ignore hash code methods- Since:
- 5.3
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setIgnoreAnnotation
public void setIgnoreAnnotation(boolean ignoreAnnotation)
Setter to ignore magic numbers in annotation declarations.- Parameters:
ignoreAnnotation
- decide whether to ignore annotations- Since:
- 5.4
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setIgnoreFieldDeclaration
public void setIgnoreFieldDeclaration(boolean ignoreFieldDeclaration)
Setter to ignore magic numbers in field declarations.- Parameters:
ignoreFieldDeclaration
- decide whether to ignore magic numbers in field declaration- Since:
- 6.6
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setIgnoreAnnotationElementDefaults
public void setIgnoreAnnotationElementDefaults(boolean ignoreAnnotationElementDefaults)
Setter to ignore magic numbers in annotation elements defaults.- Parameters:
ignoreAnnotationElementDefaults
- decide whether to ignore annotation elements defaults- Since:
- 8.23
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isChildOf
private static boolean isChildOf(DetailAST ast, int type)
Determines if the given AST node has a parent node with given token type code.- Parameters:
ast
- the AST from which to search for annotationstype
- the type code of parent token- Returns:
true
if the AST node has a parent with given token type.
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