Class ExplicitInitializationCheck
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.ExplicitInitializationCheck
- All Implemented Interfaces:
Configurable
,Contextualizable
Checks if any class or object member is explicitly initialized
to default for its type value (null
for object
references, zero for numeric types and char
and false
for boolean
.
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 there is a minor inefficiency.
-
Property
onlyObjectReferences
- control whether only explicit initializations made to null for objects should be checked. Type isboolean
. Default value isfalse
.
To configure the check:
<module name="ExplicitInitialization"/>
Example:
public class Test { private int intField1 = 0; // violation private int intField2 = 1; private int intField3; private char charField1 = '\0'; // violation private char charField2 = 'b'; private char charField3; private boolean boolField1 = false; // violation private boolean boolField2 = true; private boolean boolField3; private Obj objField1 = null; // violation private Obj objField2 = new Obj(); private Obj objField3; private int arrField1[] = null; // violation private int arrField2[] = new int[10]; private int arrField3[]; }
To configure the check so that it only checks for objects that explicitly initialize to null:
<module name="ExplicitInitialization"> <property name="onlyObjectReferences" value="true"/> </module>
Example:
public class Test { private int intField1 = 0; // ignored private int intField2 = 1; private int intField3; private char charField1 = '\0'; // ignored private char charField2 = 'b'; private char charField3; private boolean boolField1 = false; // ignored private boolean boolField2 = true; private boolean boolField3; private Obj objField1 = null; // violation private Obj objField2 = new Obj(); private Obj objField3; private int arrField1[] = null; // violation private int arrField2[] = new int[10]; private int arrField3[]; }
Parent is com.puppycrawl.tools.checkstyle.TreeWalker
Violation Message Keys:
-
explicit.init
- Since:
- 3.2
-
Nested Class Summary
Nested classes/interfaces inherited from class com.puppycrawl.tools.checkstyle.api.AutomaticBean
AutomaticBean.OutputStreamOptions
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Field Summary
Fields -
Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionfinal int[]
The configurable token set.final int[]
Returns the default token a check is interested in.final int[]
The tokens that this check must be registered for.void
setOnlyObjectReferences
(boolean onlyObjectReferences) Setter to control whether only explicit initializations made to null for objects should be checked.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
-
MSG_KEY
A key is pointing to the warning message text in "messages.properties" file.- See Also:
-
-
Constructor Details
-
ExplicitInitializationCheck
public ExplicitInitializationCheck()
-
-
Method Details
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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:
-
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:
-
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:
-
setOnlyObjectReferences
public void setOnlyObjectReferences(boolean onlyObjectReferences) Setter to control whether only explicit initializations made to null for objects should be checked.- Parameters:
onlyObjectReferences
- whether only explicit initialization made to null should be checked
-
visitToken
Description copied from class:AbstractCheck
Called to process a token.- Overrides:
visitToken
in classAbstractCheck
- Parameters:
ast
- the token to process
-