Package com.puppycrawl.tools.checkstyle.checks.blocks

Class AvoidNestedBlocksCheck

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.blocks.AvoidNestedBlocksCheck

All Implemented Interfaces:

Configurable, Contextualizable

public class AvoidNestedBlocksCheck
extends AbstractCheck

Finds nested blocks (blocks that are used freely in the code).

Rationale: Nested blocks are often leftovers from the debugging process, they confuse the reader.

For example, this check finds the obsolete braces in

 public void guessTheOutput()
 {
   int whichIsWhich = 0;
   {
     whichIsWhich = 2;
   }
   System.out.println("value = " + whichIsWhich);
 }
 

and debugging / refactoring leftovers such as

 // if (conditionThatIsNotUsedAnyLonger)
 {
   System.out.println("unconditional");
 }
 

A case in a switch statement does not implicitly form a block. Thus, to be able to introduce local variables that have case scope it is necessary to open a nested block. This is supported, set the allowInSwitchCase property to true and include all statements of the case in the block.

• Property allowInSwitchCase - Allow nested blocks if they are the only child of a switch case. Type is boolean. Default value is false.

Parent is com.puppycrawl.tools.checkstyle.TreeWalker

Violation Message Keys:

• block.nested

Since:

3.1

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 boolean	allowInSwitchCase	Allow nested blocks if they are the only child of a switch case.
static final String	MSG_KEY_BLOCK_NESTED	A key is pointing to the warning message text in "messages.properties" file.

Constructor Summary

Constructors

Constructor	Description
AvoidNestedBlocksCheck()

Method Summary

Modifier and Type	Method	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.
private static boolean	hasSiblings(DetailAST ast)	Checks whether the AST node has any siblings or not.
void	setAllowInSwitchCase(boolean allowInSwitchCase)	Setter to allow nested blocks if they are the only child of a switch case.
void	visitToken(DetailAST ast)	Called to process a token.

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

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

configure, contextualize, getConfiguration, setupChild

Methods inherited from class java.lang.Object

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

Field Details

MSG_KEY_BLOCK_NESTED

public static final String MSG_KEY_BLOCK_NESTED

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

See Also:

• Constant Field Values

allowInSwitchCase

private boolean allowInSwitchCase

Allow nested blocks if they are the only child of a switch case.

Constructor Details

AvoidNestedBlocksCheck

public AvoidNestedBlocksCheck()

Method Details

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

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

hasSiblings

private static boolean hasSiblings(DetailAST ast)

Checks whether the AST node has any siblings or not.

Parameters:

ast - node to examine

Returns:

true if the node has one or more siblings

setAllowInSwitchCase

public void setAllowInSwitchCase(boolean allowInSwitchCase)

Setter to allow nested blocks if they are the only child of a switch case.

Parameters:

allowInSwitchCase - whether nested blocks are allowed if they are the only child of a switch case.

Since:

3.2