Package com.puppycrawl.tools.checkstyle.checks.coding

Class OneStatementPerLineCheck

java.lang.Object

com.puppycrawl.tools.checkstyle.AbstractAutomaticBean

com.puppycrawl.tools.checkstyle.api.AbstractViolationReporter

com.puppycrawl.tools.checkstyle.api.AbstractCheck

com.puppycrawl.tools.checkstyle.checks.coding.OneStatementPerLineCheck

All Implemented Interfaces:

Configurable, Contextualizable

public final class OneStatementPerLineCheck
extends AbstractCheck

Checks that there is only one statement per line.

Rationale: It's very difficult to read multiple statements on one line.

In the Java programming language, statements are the fundamental unit of execution. All statements except blocks are terminated by a semicolon. Blocks are denoted by open and close curly braces.

OneStatementPerLineCheck checks the following types of statements: variable declaration statements, empty statements, import statements, assignment statements, expression statements, increment statements, object creation statements, 'for loop' statements, 'break' statements, 'continue' statements, 'return' statements, resources statements (optional).

• Property treatTryResourcesAsStatement - Enable resources processing. Type is boolean. Default value is false.

Parent is com.puppycrawl.tools.checkstyle.TreeWalker

Violation Message Keys:

• multiple.statements.line

Since:

5.3

Nested Class Summary

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

AbstractAutomaticBean.OutputStreamOptions

Field Summary

Fields

Modifier and Type	Field	Description
private Deque<Integer>	countOfSemiInLambda	Counts number of semicolons in nested lambdas.
private int	forStatementEnd	Hold the line-number where the last 'for-loop' statement ended.
private boolean	inForHeader	The for-header usually has 3 statements on one line, but THIS IS OK.
private boolean	isInLambda	Holds if current token is inside lambda.
private int	lambdaStatementEnd	Hold the line-number where the last lambda statement ended.
private int	lastStatementEnd	Hold the line-number where the last statement ended.
private int	lastVariableResourceStatementEnd	Hold the line-number where the last resource variable statement ended.
static String	MSG_KEY	A key is pointing to the warning message text in "messages.properties" file.
private boolean	treatTryResourcesAsStatement	Enable resources processing.

Constructor Summary

Constructors

Constructor	Description
OneStatementPerLineCheck()

Method Summary

Modifier and Type	Method	Description
void	beginTree(DetailAST rootAST)	Called before the starting to process a tree.
private void	checkIfSemicolonIsInDifferentLineThanPrevious(DetailAST ast)	Checks if given semicolon is in different line than previous.
private void	checkLambda(DetailAST ast, DetailAST currentStatement)	Checks semicolon placement in lambda.
private void	checkResourceVariable(DetailAST currentStatement)	Checks resource variable.
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	isOnTheSameLine(DetailAST ast, int lastStatementEnd, int forStatementEnd, int lambdaStatementEnd)	Checks whether two statements are on the same line.
private static boolean	isResource(DetailAST ast)	Checks that given node is a resource.
void	leaveToken(DetailAST ast)	Called after all the child nodes have been process.
void	setTreatTryResourcesAsStatement(boolean treatTryResourcesAsStatement)	Setter to enable resources processing.
void	visitToken(DetailAST ast)	Called to process a token.

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

clearViolations, destroy, finishTree, getFileContents, getFilePath, getLine, getLineCodePoints, getLines, getTabWidth, getTokenNames, getViolations, init, isCommentNodesRequired, 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.AbstractAutomaticBean

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

countOfSemiInLambda

private final Deque<Integer> countOfSemiInLambda

Counts number of semicolons in nested lambdas.

lastStatementEnd

private int lastStatementEnd

Hold the line-number where the last statement ended.

forStatementEnd

private int forStatementEnd

Hold the line-number where the last 'for-loop' statement ended.

inForHeader

private boolean inForHeader

The for-header usually has 3 statements on one line, but THIS IS OK.

isInLambda

private boolean isInLambda

Holds if current token is inside lambda.

lambdaStatementEnd

private int lambdaStatementEnd

Hold the line-number where the last lambda statement ended.

lastVariableResourceStatementEnd

private int lastVariableResourceStatementEnd

Hold the line-number where the last resource variable statement ended.

treatTryResourcesAsStatement

private boolean treatTryResourcesAsStatement

Enable resources processing.

Constructor Detail

OneStatementPerLineCheck

public OneStatementPerLineCheck()

Method Detail

setTreatTryResourcesAsStatement

public void setTreatTryResourcesAsStatement(boolean treatTryResourcesAsStatement)

Setter to enable resources processing.

Parameters:

treatTryResourcesAsStatement - user's value of treatTryResourcesAsStatement.

Since:

8.23

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

leaveToken

public void leaveToken(DetailAST ast)

Description copied from class: AbstractCheck

Called after all the child nodes have been process.

Overrides:

leaveToken in class AbstractCheck

Parameters:

ast - the token leaving

checkIfSemicolonIsInDifferentLineThanPrevious

private void checkIfSemicolonIsInDifferentLineThanPrevious(DetailAST ast)

Checks if given semicolon is in different line than previous.

Parameters:

ast - semicolon to check

checkLambda

private void checkLambda(DetailAST ast,
                         DetailAST currentStatement)

Checks semicolon placement in lambda.

Parameters:

ast - semicolon to check

currentStatement - current statement

isResource

private static boolean isResource(DetailAST ast)

Checks that given node is a resource.

Parameters:

ast - semicolon to check

Returns:

true if node is a resource

checkResourceVariable

private void checkResourceVariable(DetailAST currentStatement)

Checks resource variable.

Parameters:

currentStatement - current statement

isOnTheSameLine

private static boolean isOnTheSameLine(DetailAST ast,
                                       int lastStatementEnd,
                                       int forStatementEnd,
                                       int lambdaStatementEnd)

Checks whether two statements are on the same line.

Parameters:

ast - token for the current statement.

lastStatementEnd - the line-number where the last statement ended.

forStatementEnd - the line-number where the last 'for-loop' statement ended.

lambdaStatementEnd - the line-number where the last lambda statement ended.

Returns:

true if two statements are on the same line.