com.github.sevntu.checkstyle.checks.coding

Class AvoidConstantAsFirstOperandInConditionCheck

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.AvoidConstantAsFirstOperandInConditionCheck

All Implemented Interfaces:

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

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

Checks that constants do not appear in the first operand of any condition.

If comparing values, C(C++) developers prefer to put the constant first in the equality check, to prevent situations of assignment rather than equality checking. It is easy to write "=" instead of "==", and no compile error will be produced but condition will work in a different way then intended. However, in Java it is impossible to use assignment inside the if condition, so that habit becomes unnecessary and does damage to the readability of the code.

This check was extended to include all equality checks like ">", ">=", "<", "<=" for users who prefer constants always be on the right-hand side for any condition.

Example: if (null == variable) rather than if (variable == null) because if you forget one (typo mistake) of the equal sign, you end up with if (variable = null) which assigns null to variable and IF always evaluate to true.

Since:

1.9.0

Author:

Sergey Burtsev

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
AvoidConstantAsFirstOperandInConditionCheck()

Method Summary

Modifier and Type	Method and Description
int[]	getAcceptableTokens()
int[]	getDefaultTokens()
int[]	getRequiredTokens()
void	setTargetConstantTypes(String... targets) Set target constant types.
void	visitToken(com.puppycrawl.tools.checkstyle.api.DetailAST detailAST)

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

AvoidConstantAsFirstOperandInConditionCheck

public AvoidConstantAsFirstOperandInConditionCheck()

Method Detail

setTargetConstantTypes

public void setTargetConstantTypes(String... targets)

Set target constant types.

Parameters:

targets - target constant types

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

visitToken

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

Overrides:

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