com.puppycrawl.tools.checkstyle.checks

Class AvoidEscapedUnicodeCharactersCheck

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.AvoidEscapedUnicodeCharactersCheck

All Implemented Interfaces:

Configurable, Contextualizable

public class AvoidEscapedUnicodeCharactersCheck
extends AbstractCheck

Restricts using Unicode escapes (such as \u221e). It is possible to allow using escapes for non-printable, control characters. Also, this check can be configured to allow using escapes if trail comment is present. By the option it is possible to allow using escapes if literal contains only them.

• Property allowEscapesForControlCharacters - Allow use escapes for non-printable, control characters. Type is boolean. Default value is false.
• Property allowByTailComment - Allow use escapes if trail comment is present. Type is boolean. Default value is false.
• Property allowIfAllCharactersEscaped - Allow if all characters in literal are escaped. Type is boolean. Default value is false.
• Property allowNonPrintableEscapes - Allow use escapes for non-printable, whitespace characters. Type is boolean. Default value is false.

Examples of using Unicode:

 String unitAbbrev = "μs";      // Best: perfectly clear even without a comment.
 String unitAbbrev = "\u03bcs"; // Poor: the reader has no idea what this is.
 

An example of how to configure the check is:

 <module name="AvoidEscapedUnicodeCharacters"/>
 

An example of non-printable, control characters.

 return '\ufeff' + content; // byte order mark
 

An example of how to configure the check to allow using escapes for non-printable, control characters:

 <module name="AvoidEscapedUnicodeCharacters">
   <property name="allowEscapesForControlCharacters" value="true"/>
 </module>
 

Example of using escapes with trail comment:

 String unitAbbrev = "\u03bcs"; // Greek letter mu, "s"
 

An example of how to configure the check to allow using escapes if trail comment is present:

 <module name="AvoidEscapedUnicodeCharacters">
   <property name="allowByTailComment" value="true"/>
 </module>
 

Example of using escapes if literal contains only them:

 String unitAbbrev = "\u03bc\u03bc\u03bc";
 

An example of how to configure the check to allow escapes if literal contains only them:

 <module name="AvoidEscapedUnicodeCharacters">
   <property name="allowIfAllCharactersEscaped" value="true"/>
 </module>
 

An example of how to configure the check to allow using escapes for non-printable, whitespace characters:

 <module name="AvoidEscapedUnicodeCharacters">
   <property name="allowNonPrintableEscapes" value="true"/>
 </module>
 

Parent is com.puppycrawl.tools.checkstyle.TreeWalker

Violation Message Keys:

• forbid.escaped.unicode.char

Since:

5.8

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
AvoidEscapedUnicodeCharactersCheck()

Method Summary

Modifier and Type	Method and Description
void	beginTree(DetailAST rootAST) Called before the starting to process a tree.
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	setAllowByTailComment(boolean allow) Setter to allow use escapes if trail comment is present.
void	setAllowEscapesForControlCharacters(boolean allow) Setter to allow use escapes for non-printable, control characters.
void	setAllowIfAllCharactersEscaped(boolean allow) Setter to allow if all characters in literal are escaped.
void	setAllowNonPrintableEscapes(boolean allow) Setter to allow use escapes for non-printable, whitespace characters.
void	visitToken(DetailAST ast) Called to process a token.

Methods inherited from class com.puppycrawl.tools.checkstyle.api.AbstractCheck

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

AvoidEscapedUnicodeCharactersCheck

public AvoidEscapedUnicodeCharactersCheck()

Method Detail

setAllowEscapesForControlCharacters

public final void setAllowEscapesForControlCharacters(boolean allow)

Setter to allow use escapes for non-printable, control characters.

Parameters:

allow - user's value.

setAllowByTailComment

public final void setAllowByTailComment(boolean allow)

Setter to allow use escapes if trail comment is present.

Parameters:

allow - user's value.

setAllowIfAllCharactersEscaped

public final void setAllowIfAllCharactersEscaped(boolean allow)

Setter to allow if all characters in literal are escaped.

Parameters:

allow - user's value.

setAllowNonPrintableEscapes

public final void setAllowNonPrintableEscapes(boolean allow)

Setter to allow use escapes for non-printable, whitespace characters.

Parameters:

allow - user's value.

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

beginTree

public void beginTree(DetailAST rootAST)

Description copied from class: AbstractCheck

Called before the starting to process a tree. Ideal place to initialize information that is to be collected whilst processing a tree.

Overrides:

beginTree in class AbstractCheck

Parameters:

rootAST - the root of the tree

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