com.github.sevntu.checkstyle.checks.coding

Class TernaryPerExpressionCountCheck

java.lang.Object

com.puppycrawl.tools.checkstyle.api.AutomaticBean

com.puppycrawl.tools.checkstyle.api.AbstractViolationReporter

com.puppycrawl.tools.checkstyle.api.AbstractCheck

com.github.sevntu.checkstyle.checks.coding.TernaryPerExpressionCountCheck

All Implemented Interfaces:

com.puppycrawl.tools.checkstyle.api.Configurable, com.puppycrawl.tools.checkstyle.api.Contextualizable

public class TernaryPerExpressionCountCheck
extends com.puppycrawl.tools.checkstyle.api.AbstractCheck

Restricts the number of ternary operators in expression to a specific limit.

Rationale: This Check helps to improve code readability by pointing developer on
expressions which contain more than user-defined count of ternary operators.

It points to complicated ternary expressions. Reason:
- Complicated ternary expressions are not easy to read.
- Complicated ternary expressions could lead to ambiguous result if user
does not know Java's operators priority well, e.g.:

 String str = null;
 String x = str != null ? "A" : "B" + str == null ? "C" : "D";
 System.out.println(x);
 

Output for code above is "D", but more obvious would be "BC".

Check has following properties:

• maxTernaryPerExpressionCount - limit of ternary operators per expression
  
• ignoreTernaryOperatorsInBraces - if true Check will ignore ternary operators
  in braces (braces explicitly set priority level)
  
• ignoreIsolatedTernaryOnLine - if true Check will ignore one line ternary operators,
  if only it is places in line alone.
  

Options ignoreTernaryOperatorsInBraces and ignoreIsolatedTernaryOnLine can
make Check less strict, e.g.:
Using ignoreTernaryOperatorsInBraces option (value = true)
does not put violation on code below:

 callString = "{? = call " +
   (StringUtils.hasLength(catalogNameToUse)
   ? catalogNameToUse + "." : "") +
   (StringUtils.hasLength(schemaNameToUse)
   ? schemaNameToUse + "." : "") +
   procedureNameToUse + "(";
 

When using ignoreIsolatedTernaryOnLine (value = true), even without
ignoreTernaryOperatorsInBraces option Check won't warn on code below:

 int a = (d == 5) ? d : f
   +
   ((d == 6) ? g : k);
 

Since:

1.12.0

Author:

Aleksey Nesterenko

Nested Class Summary

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

com.puppycrawl.tools.checkstyle.api.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
TernaryPerExpressionCountCheck()

Method Summary

Modifier and Type	Method and Description
int[]	getAcceptableTokens()
int[]	getDefaultTokens()
int[]	getRequiredTokens()
void	setIgnoreIsolatedTernaryOnLine(boolean ignoreIsolatedTernaryOnLine) Sets parameter to ignore expressions in case if ternary operator is isolated in line.
void	setIgnoreTernaryOperatorsInBraces(boolean ignoreTernaryOperatorsInBraces) Sets parameter to ignore ternary operators in braces, default value = true.
void	setMaxTernaryPerExpressionCount(int maxTernaryPerExpressionCount) Sets the maximum number of ternary operators, default value = 1.
void	visitToken(com.puppycrawl.tools.checkstyle.api.DetailAST expressionNode)

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

TernaryPerExpressionCountCheck

public TernaryPerExpressionCountCheck()

Method Detail

getDefaultTokens

public int[] getDefaultTokens()

Specified by:

getDefaultTokens in class com.puppycrawl.tools.checkstyle.api.AbstractCheck

getAcceptableTokens

public int[] getAcceptableTokens()

Specified by:

getAcceptableTokens in class com.puppycrawl.tools.checkstyle.api.AbstractCheck

getRequiredTokens

public int[] getRequiredTokens()

Specified by:

getRequiredTokens in class com.puppycrawl.tools.checkstyle.api.AbstractCheck

setMaxTernaryPerExpressionCount

public void setMaxTernaryPerExpressionCount(int maxTernaryPerExpressionCount)

Sets the maximum number of ternary operators, default value = 1.

Parameters:

maxTernaryPerExpressionCount - Number of ternary operators per expression

Throws:

IllegalArgumentException - when maxTernaryPerExpressionCount less zero

setIgnoreTernaryOperatorsInBraces

public void setIgnoreTernaryOperatorsInBraces(boolean ignoreTernaryOperatorsInBraces)

Sets parameter to ignore ternary operators in braces, default value = true.

Parameters:

ignoreTernaryOperatorsInBraces - ignore ternary operators in braces

setIgnoreIsolatedTernaryOnLine

public void setIgnoreIsolatedTernaryOnLine(boolean ignoreIsolatedTernaryOnLine)

Sets parameter to ignore expressions in case if ternary operator is isolated in line.

Parameters:

ignoreIsolatedTernaryOnLine - ignore expressions in case if ternary operator is isolated in line

visitToken

public void visitToken(com.puppycrawl.tools.checkstyle.api.DetailAST expressionNode)

Overrides:

visitToken in class com.puppycrawl.tools.checkstyle.api.AbstractCheck