com.puppycrawl.tools.checkstyle.checks.whitespace

Class SingleSpaceSeparatorCheck

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.whitespace.SingleSpaceSeparatorCheck

All Implemented Interfaces:

Configurable, Contextualizable

public class SingleSpaceSeparatorCheck
extends AbstractCheck

Checks that non-whitespace characters are separated by no more than one whitespace. Separating characters by tabs or multiple spaces will be reported. Currently the check doesn't permit horizontal alignment. To inspect whitespaces before and after comments, set the property validateComments to true.

Setting validateComments to false will ignore cases like:

 int i;  // Multiple whitespaces before comment tokens will be ignored.
 private void foo(int  /* whitespaces before and after block-comments will be
 ignored */  i) {
 

Sometimes, users like to space similar items on different lines to the same column position for easier reading. This feature isn't supported by this check, so both braces in the following case will be reported as violations.

 public long toNanos(long d)  { return d;             } // 2 violations
 public long toMicros(long d) { return d / (C1 / C0); }
 

• Property validateComments - Control whether to validate whitespaces surrounding comments. Type is boolean. Default value is false.

To configure the check:

 <module name="SingleSpaceSeparator"/>
 

Example:

 int foo()   { // violation, 3 whitespaces
   return  1; // violation, 2 whitespaces
 }
 int fun1() { // OK, 1 whitespace
   return 3; // OK, 1 whitespace
 }
 void  fun2() {} // violation, 2 whitespaces
 

To configure the check so that it validates comments:

 <module name="SingleSpaceSeparator">
   <property name="validateComments" value="true"/>
 </module>
 

Example:

 void fun1() {}  // violation, 2 whitespaces before the comment starts
 void fun2() { return; }  /* violation here, 2 whitespaces before the comment starts */

 /* violation, 2 whitespaces after the comment ends */  int a;

 String s; /* OK, 1 whitespace */

 /**
 * This is a Javadoc comment
 */  int b; // violation, 2 whitespaces after the javadoc comment ends

 float f1; // OK, 1 whitespace

 /**
 * OK, 1 white space after the doc comment ends
 */ float f2;
 

Parent is com.puppycrawl.tools.checkstyle.TreeWalker

Violation Message Keys:

• single.space.separator

Since:

6.19

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 java.lang.String	MSG_KEY A key is pointing to the warning message text in "messages.properties" file.
private boolean	validateComments Control whether to validate whitespaces surrounding comments.

Constructor Summary

Constructors

Constructor and Description
SingleSpaceSeparatorCheck()

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.
private static boolean	isBlockCommentEnd(java.lang.String line, int columnNo) Checks if the line at columnNo is the end of a comment, '*/'.
boolean	isCommentNodesRequired() Whether comment nodes are required or not.
private static boolean	isFirstInLine(java.lang.String line, int columnNo) Checks if the line up to and including columnNo is all non-whitespace text encountered.
private static boolean	isSingleSpace(java.lang.String line, int columnNo) Checks if the line at columnNo is a single space, and not preceded by another space.
private static boolean	isSpace(java.lang.String line, int columnNo) Checks if the line at columnNo is a space.
private boolean	isTextSeparatedCorrectlyFromPrevious(java.lang.String line, int columnNo) Checks if characters in line at and around columnNo has the correct number of spaces.
private static boolean	isWhitespace(java.lang.String line, int columnNo) Checks if the line at columnNo is a whitespace character.
void	setValidateComments(boolean validateComments) Setter to control whether to validate whitespaces surrounding comments.
private void	visitEachToken(DetailAST node) Examines every sibling and child of node for violations.

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

clearViolations, destroy, finishTree, getFileContents, getLine, getLineCodePoints, getLines, getTabWidth, getTokenNames, getViolations, init, leaveToken, log, log, log, setFileContents, setTabWidth, setTokens, visitToken

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 java.lang.String MSG_KEY

A key is pointing to the warning message text in "messages.properties" file.

See Also:

Constant Field Values

validateComments

private boolean validateComments

Control whether to validate whitespaces surrounding comments.

Constructor Detail

SingleSpaceSeparatorCheck

public SingleSpaceSeparatorCheck()

Method Detail

setValidateComments

public void setValidateComments(boolean validateComments)

Setter to control whether to validate whitespaces surrounding comments.

Parameters:

validateComments - true to validate surrounding whitespaces at comments.

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

isCommentNodesRequired

public boolean isCommentNodesRequired()

Description copied from class: AbstractCheck

Whether comment nodes are required or not.

Overrides:

isCommentNodesRequired in class AbstractCheck

Returns:

false as a default value.

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

visitEachToken

private void visitEachToken(DetailAST node)

Examines every sibling and child of node for violations.

Parameters:

node - The node to start examining.

isTextSeparatedCorrectlyFromPrevious

private boolean isTextSeparatedCorrectlyFromPrevious(java.lang.String line,
                                                     int columnNo)

Checks if characters in line at and around columnNo has the correct number of spaces. to return true the following conditions must be met:

• the character at columnNo is the first in the line.
• the character at columnNo is not separated by whitespaces from the previous non-whitespace character.
• the character at columnNo is separated by only one whitespace from the previous non-whitespace character.
• validateComments is disabled and the previous text is the end of a block comment.

Parameters:

line - The line in the file to examine.

columnNo - The column position in the line to examine.

Returns:

true if the text at columnNo is separated correctly from the previous token.

isSingleSpace

private static boolean isSingleSpace(java.lang.String line,
                                     int columnNo)

Checks if the line at columnNo is a single space, and not preceded by another space.

Parameters:

line - The line in the file to examine.

columnNo - The column position in the line to examine.

Returns:

true if the character at columnNo is a space, and not preceded by another space.

isSpace

private static boolean isSpace(java.lang.String line,
                               int columnNo)

Checks if the line at columnNo is a space.

Parameters:

line - The line in the file to examine.

columnNo - The column position in the line to examine.

Returns:

true if the character at columnNo is a space.

isWhitespace

private static boolean isWhitespace(java.lang.String line,
                                    int columnNo)

Checks if the line at columnNo is a whitespace character.

Parameters:

line - The line in the file to examine.

columnNo - The column position in the line to examine.

Returns:

true if the character at columnNo is a whitespace.

isFirstInLine

private static boolean isFirstInLine(java.lang.String line,
                                     int columnNo)

Checks if the line up to and including columnNo is all non-whitespace text encountered.

Parameters:

line - The line in the file to examine.

columnNo - The column position in the line to examine.

Returns:

true if the column position is the first non-whitespace text on the line.

isBlockCommentEnd

private static boolean isBlockCommentEnd(java.lang.String line,
                                         int columnNo)

Checks if the line at columnNo is the end of a comment, '*/'.

Parameters:

line - The line in the file to examine.

columnNo - The column position in the line to examine.

Returns:

true if the previous text is a end comment block.