com.puppycrawl.tools.checkstyle.checks.imports

Class AvoidStarImportCheck

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.imports.AvoidStarImportCheck

All Implemented Interfaces:

Configurable, Contextualizable

public class AvoidStarImportCheck
extends AbstractCheck

Checks that there are no import statements that use the * notation.

Rationale: Importing all classes from a package or static members from a class leads to tight coupling between packages or classes and might lead to problems when a new version of a library introduces name clashes.

Note that property excludes is not recursive, subpackages of excluded packages are not automatically excluded.

• Property excludes - Specify packages where star imports are allowed. Type is java.lang.String[]. Default value is {}.
• Property allowClassImports - Control whether to allow starred class imports like import java.util.*;. Type is boolean. Default value is false.
• Property allowStaticMemberImports - Control whether to allow starred static member imports like import static org.junit.Assert.*;. Type is boolean. Default value is false.

To configure the check:

 <module name="AvoidStarImport"/>
 

Example:

 import java.util.Scanner;         // OK
 import java.io.*;                 // violation
 import static java.lang.Math.*;   // violation
 import java.util.*;               // violation
 import java.net.*;                // violation
 

To configure the check so that star imports from packages java.io and java.net as well as static members from class java.lang.Math are allowed:

 <module name="AvoidStarImport">
   <property name="excludes" value="java.io,java.net,java.lang.Math"/>
 </module>
 

Example:

 import java.util.Scanner;         // OK
 import java.io.*;                 // OK
 import static java.lang.Math.*;   // OK
 import java.util.*;               // violation
 import java.net.*;                // OK
 

To configure the check so that star imports from all packages are allowed:

 <module name="AvoidStarImport">
   <property name="allowClassImports" value="true"/>
 </module>
 

Example:

 import java.util.Scanner;         // OK
 import java.io.*;                 // OK
 import static java.lang.Math.*;   // violation
 import java.util.*;               // OK
 import java.net.*;                // OK
 

To configure the check so that starred static member imports from all packages are allowed:

 <module name="AvoidStarImport">
   <property name="allowStaticMemberImports" value="true"/>
 </module>
 

Example:

 import java.util.Scanner;         // OK
 import java.io.*;                 // violation
 import static java.lang.Math.*;   // OK
 import java.util.*;               // violation
 import java.net.*;                // violation
 

Parent is com.puppycrawl.tools.checkstyle.TreeWalker

Violation Message Keys:

• import.avoidStar

Since:

3.0

Nested Class Summary

Nested classes/interfaces inherited from class com.puppycrawl.tools.checkstyle.api.AutomaticBean

AutomaticBean.OutputStreamOptions

Field Summary

Fields

Modifier and Type	Field and Description
static String	MSG_KEY A key is pointing to the warning message text in "messages.properties" file.

Constructor Summary

Constructors

Constructor and Description
AvoidStarImportCheck()

Method Summary

Modifier and Type	Method and 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.
void	setAllowClassImports(boolean allow) Setter to control whether to allow starred class imports like import java.util.*;.
void	setAllowStaticMemberImports(boolean allow) Setter to control whether to allow starred static member imports like import static org.junit.Assert.*;.
void	setExcludes(String... excludesParam) Setter to specify packages where star imports are allowed.
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

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

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

Constructor Detail

AvoidStarImportCheck

public AvoidStarImportCheck()

Method Detail

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 class AbstractCheck

Returns:

the default tokens

See Also:

TokenTypes

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 class AbstractCheck

Returns:

the token set this check is designed for.

See Also:

TokenTypes

getRequiredTokens

public int[] getRequiredTokens()

Description copied from class: AbstractCheck

The tokens that this check must be registered for.

Specified by:

getRequiredTokens in class AbstractCheck

Returns:

the token set this must be registered for.

See Also:

TokenTypes

setExcludes

public void setExcludes(String... excludesParam)

Setter to specify packages where star imports are allowed.

Parameters:

excludesParam - a list of package names/fully-qualifies class names where star imports are ok.

setAllowClassImports

public void setAllowClassImports(boolean allow)

Setter to control whether to allow starred class imports like import java.util.*;.

Parameters:

allow - true to allow false to disallow

setAllowStaticMemberImports

public void setAllowStaticMemberImports(boolean allow)

Setter to control whether to allow starred static member imports like import static org.junit.Assert.*;.

Parameters:

allow - true to allow false to disallow

visitToken

public void visitToken(DetailAST ast)

Description copied from class: AbstractCheck

Called to process a token.

Overrides:

visitToken in class AbstractCheck

Parameters:

ast - the token to process