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

Class NeedBracesCheck

  • All Implemented Interfaces:
    Configurable, Contextualizable
    public class NeedBracesCheck
extends AbstractCheck

    Checks for braces around code blocks.

    By default the check will check the following blocks: LITERAL_DO, LITERAL_ELSE, LITERAL_FOR, LITERAL_IF, LITERAL_WHILE.

    An example of how to configure the check is: 

     <module name="NeedBraces"/>

    An example of how to configure the check for if and else blocks is: 

     <module name="NeedBraces">
     <property name="tokens" value="LITERAL_IF, LITERAL_ELSE"/>
 </module>
    Check has the following options:

    allowSingleLineStatement which allows single-line statements without braces, e.g.:

    if (obj.isValid()) return true;

    while (obj.isValid()) return true;

    do this.notify(); while (o != null);

    for (int i = 0; ; ) this.notify();

    allowEmptyLoopBody which allows loops with empty bodies, e.g.:

    while (value.incrementValue() < 5);

    for(int i = 0; i < 10; value.incrementValue());

    Default value for allowEmptyLoopBody option is false.

    To configure the Check to allow case, default single-line statements without braces: 

     <module name="NeedBraces">
     <property name="tokens" value="LITERAL_CASE, LITERAL_DEFAULT"/>
     <property name="allowSingleLineStatement" value="true"/>
 </module>

    Such statements would be allowed: 

     
 switch (num) {
     case 1: counter++; break; // OK
     case 6: counter += 10; break; // OK
     default: counter = 100; break; // OK
 }

    To configure the Check to allow while, for loops with empty bodies: 

     <module name="NeedBraces">
     <property name="allowEmptyLoopBody" value="true"/>
 </module>

    Such statements would be allowed: 

     
 while (value.incrementValue() &lt; 5); // OK
 for(int i = 0; i &lt; 10; value.incrementValue()); // OK

    • Field Detail

      • MSG_KEY_NEED_BRACES

        public static final java.lang.String MSG_KEY_NEED_BRACES
        A key is pointing to the warning message text in "messages.properties" file.
        See Also:
        Constant Field Values

      • allowSingleLineStatement

        private boolean allowSingleLineStatement
        Check's option for skipping single-line statements.

      • allowEmptyLoopBody

        private boolean allowEmptyLoopBody
        Check's option for allowing loops with empty body.

    • Constructor Detail

      • NeedBracesCheck

        public NeedBracesCheck()

    • Method Detail

      • setAllowSingleLineStatement

        public void setAllowSingleLineStatement​(boolean allowSingleLineStatement)
        Setter.
        Parameters:
        allowSingleLineStatement - Check's option for skipping single-line statements

      • setAllowEmptyLoopBody

        public void setAllowEmptyLoopBody​(boolean allowEmptyLoopBody)
        Sets whether to allow empty loop body.
        Parameters:
        allowEmptyLoopBody - Check's option for allowing loops with empty body.

      • 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

      • isDefaultInAnnotation

        private boolean isDefaultInAnnotation​(DetailAST ast)
        Checks if ast is the default token of an annotation field.
        Parameters:
        ast - ast to test.
        Returns:
        true if current ast is default and it is part of annotation.

      • isSkipStatement

        private boolean isSkipStatement​(DetailAST statement)
        Checks if current statement can be skipped by "need braces" warning.
        Parameters:
        statement - if, for, while, do-while, lambda, else, case, default statements.
        Returns:
        true if current statement can be skipped by Check.

      • isEmptyLoopBody

        private static boolean isEmptyLoopBody​(DetailAST ast)
        Checks if current loop statement does not have body, e.g.:

        while (value.incrementValue() < 5); ... for(int i = 0; i < 10; value.incrementValue());

        Parameters:
        ast - ast token.
        Returns:
        true if current loop statement does not have body.

      • isSingleLineStatement

        private static boolean isSingleLineStatement​(DetailAST statement)
        Checks if current statement is single-line statement, e.g.:

        if (obj.isValid()) return true;

        while (obj.isValid()) return true;

        Parameters:
        statement - if, for, while, do-while, lambda, else, case, default statements.
        Returns:
        true if current statement is single-line statement.

      • isSingleLineWhile

        private static boolean isSingleLineWhile​(DetailAST literalWhile)
        Checks if current while statement is single-line statement, e.g.:

        while (obj.isValid()) return true;

        Parameters:
        literalWhile - while statement.
        Returns:
        true if current while statement is single-line statement.

      • isSingleLineDoWhile

        private static boolean isSingleLineDoWhile​(DetailAST literalDo)
        Checks if current do-while statement is single-line statement, e.g.:

        do this.notify(); while (o != null);

        Parameters:
        literalDo - do-while statement.
        Returns:
        true if current do-while statement is single-line statement.

      • isSingleLineFor

        private static boolean isSingleLineFor​(DetailAST literalFor)
        Checks if current for statement is single-line statement, e.g.:

        for (int i = 0; ; ) this.notify();

        Parameters:
        literalFor - for statement.
        Returns:
        true if current for statement is single-line statement.

      • isSingleLineIf

        private static boolean isSingleLineIf​(DetailAST literalIf)
        Checks if current if statement is single-line statement, e.g.:

        if (obj.isValid()) return true;

        Parameters:
        literalIf - if statement.
        Returns:
        true if current if statement is single-line statement.

      • isSingleLineLambda

        private static boolean isSingleLineLambda​(DetailAST lambda)
        Checks if current lambda statement is single-line statement, e.g.:

        Runnable r = () -> System.out.println("Hello, world!");

        Parameters:
        lambda - lambda statement.
        Returns:
        true if current lambda statement is single-line statement.

      • isSingleLineCase

        private static boolean isSingleLineCase​(DetailAST literalCase)
        Checks if current case statement is single-line statement, e.g.:

        case 1: doSomeStuff(); break; case 2: doSomeStuff(); break; case 3: ;

        Parameters:
        literalCase - case statement.
        Returns:
        true if current case statement is single-line statement.

      • isSingleLineDefault

        private static boolean isSingleLineDefault​(DetailAST literalDefault)
        Checks if current default statement is single-line statement, e.g.:

        default: doSomeStuff();

        Parameters:
        literalDefault - default statement.
        Returns:
        true if current default statement is single-line statement.

      • isSingleLineElse

        private static boolean isSingleLineElse​(DetailAST literalElse)
        Checks if current else statement is single-line statement, e.g.:

        else doSomeStuff();

        Parameters:
        literalElse - else statement.
        Returns:
        true if current else statement is single-line statement.