Class ExplicitInitializationCheck
- java.lang.Object
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- com.puppycrawl.tools.checkstyle.api.AutomaticBean
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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.ExplicitInitializationCheck
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- All Implemented Interfaces:
Configurable
,Contextualizable
public class ExplicitInitializationCheck extends AbstractCheck
Checks if any class or object member explicitly initialized to default for its type value (
null
for object references, zero for numeric types andchar
andfalse
forboolean
.Rationale: each instance variable gets initialized twice, to the same value. Java initializes each instance variable to its default value (0 or null) before performing any initialization specified in the code. So in this case, x gets initialized to 0 twice, and bar gets initialized to null twice. So there is a minor inefficiency. This style of coding is a hold-over from C/C++ style coding, and it shows that the developer isn't really confident that Java really initializes instance variables to default values.
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Field Summary
Fields Modifier and Type Field Description static java.lang.String
MSG_KEY
A key is pointing to the warning message text in "messages.properties" file.private boolean
onlyObjectReferences
Whether only explicit initialization made to null should be checked.
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Constructor Summary
Constructors Constructor Description ExplicitInitializationCheck()
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description 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
isNumericType(int type)
Determine if a given type is a numeric type.private static boolean
isObjectType(DetailAST type)
Determines if a given type is an object type.private static boolean
isSkipCase(DetailAST ast)
Checks for cases that should be skipped: no assignment, local variable, final variables.private static boolean
isZero(DetailAST expr)
Checks if given node contains numeric constant for zero.private static boolean
isZeroChar(DetailAST exprStart)
Examine char literal for initializing to default value.void
setOnlyObjectReferences(boolean onlyObjectReferences)
Sets whether only explicit initialization made to null should be checked.private void
validateNonObjects(DetailAST ast)
Checks for explicit initializations made to 'false', '0' and '\0'.void
visitToken(DetailAST ast)
Called to process a token.-
Methods inherited from class com.puppycrawl.tools.checkstyle.api.AbstractCheck
beginTree, destroy, finishTree, getClassLoader, getFileContents, getLine, getLines, getTabWidth, getTokenNames, init, isCommentNodesRequired, leaveToken, log, log, setClassLoader, setFileContents, setMessages, setTabWidth, setTokens
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Methods inherited from class com.puppycrawl.tools.checkstyle.api.AbstractViolationReporter
getCustomMessages, getId, getMessageBundle, getSeverity, getSeverityLevel, log, setId, setSeverity
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Methods inherited from class com.puppycrawl.tools.checkstyle.api.AutomaticBean
configure, contextualize, finishLocalSetup, getConfiguration, setupChild
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Field Detail
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MSG_KEY
public static final java.lang.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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onlyObjectReferences
private boolean onlyObjectReferences
Whether only explicit initialization made to null should be checked.
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Method Detail
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getDefaultTokens
public final 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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getRequiredTokens
public final 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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getAcceptableTokens
public final 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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setOnlyObjectReferences
public void setOnlyObjectReferences(boolean onlyObjectReferences)
Sets whether only explicit initialization made to null should be checked.- Parameters:
onlyObjectReferences
- whether only explicit initialization made to null should be checked
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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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validateNonObjects
private void validateNonObjects(DetailAST ast)
Checks for explicit initializations made to 'false', '0' and '\0'.- Parameters:
ast
- token being checked for explicit initializations
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isZeroChar
private static boolean isZeroChar(DetailAST exprStart)
Examine char literal for initializing to default value.- Parameters:
exprStart
- expression- Returns:
- true is literal is initialized by zero symbol
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isSkipCase
private static boolean isSkipCase(DetailAST ast)
Checks for cases that should be skipped: no assignment, local variable, final variables.- Parameters:
ast
- Variable def AST- Returns:
- true is that is a case that need to be skipped.
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isObjectType
private static boolean isObjectType(DetailAST type)
Determines if a given type is an object type.- Parameters:
type
- type to check.- Returns:
- true if it is an object type.
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isNumericType
private static boolean isNumericType(int type)
Determine if a given type is a numeric type.- Parameters:
type
- code of the type for check.- Returns:
- true if it's a numeric type.
- See Also:
TokenTypes
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isZero
private static boolean isZero(DetailAST expr)
Checks if given node contains numeric constant for zero.- Parameters:
expr
- node to check.- Returns:
- true if given node contains numeric constant for zero.
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