DescendantTokenCheck (checkstyle 9.3 API)

java.lang.Object
- com.puppycrawl.tools.checkstyle.api.AutomaticBean
- - com.puppycrawl.tools.checkstyle.api.AbstractViolationReporter
  - - com.puppycrawl.tools.checkstyle.api.AbstractCheck
    - - com.puppycrawl.tools.checkstyle.checks.DescendantTokenCheck

All Implemented Interfaces:: Configurable, Contextualizable

public class DescendantTokenCheck
extends AbstractCheck

Checks for restricted tokens beneath other tokens.

WARNING: This is a very powerful and flexible check, but, at the same time, it is low-level and very implementation-dependent because its results depend on the grammar we use to build abstract syntax trees. Thus we recommend using other checks when they provide the desired functionality. Essentially, this check just works on the level of an abstract syntax tree and knows nothing about language structures.

Property limitedTokens - Specify set of tokens with limited occurrences as descendants. Type is java.lang.String[]. Validation type is tokenTypesSet. Default value is "".
Property minimumDepth - Specify the minimum depth for descendant counts. Type is int. Default value is 0.
Property maximumDepth - Specify the maximum depth for descendant counts. Type is int. Default value is 2147483647.
Property minimumNumber - Specify a minimum count for descendants. Type is int. Default value is 0.
Property maximumNumber - Specify a maximum count for descendants. Type is int. Default value is 2147483647.
Property sumTokenCounts - Control whether the number of tokens found should be calculated from the sum of the individual token counts. Type is boolean. Default value is false.
Property minimumMessage - Define the violation message when the minimum count is not reached. Type is java.lang.String. Default value is null.
Property maximumMessage - Define the violation message when the maximum count is exceeded. Type is java.lang.String. Default value is null.
Property tokens - tokens to check Type is anyTokenTypesSet. Default value is "".

To configure the check to produce a violation on a switch statement with no default case:

 <module name="DescendantToken">
   <property name="tokens" value="LITERAL_SWITCH"/>
   <property name="maximumDepth" value="2"/>
   <property name="limitedTokens" value="LITERAL_DEFAULT"/>
   <property name="minimumNumber" value="1"/>
 </module>

To configure the check to produce a violation on a condition in for which performs no check:

 <module name="DescendantToken">
   <property name="tokens" value="FOR_CONDITION"/>
   <property name="limitedTokens" value="EXPR"/>
   <property name="minimumNumber" value="1"/>
 </module>

To configure the check to produce a violation on comparing this with null(i.e. this == null and this != null):

 <module name="DescendantToken">
   <property name="tokens" value="EQUAL,NOT_EQUAL"/>
   <property name="limitedTokens" value="LITERAL_THIS,LITERAL_NULL"/>
   <property name="maximumNumber" value="1"/>
   <property name="maximumDepth" value="1"/>
   <property name="sumTokenCounts" value="true"/>
 </module>

To configure the check to produce a violation on a String literal equality check:

 <module name="DescendantToken">
   <property name="tokens" value="EQUAL,NOT_EQUAL"/>
   <property name="limitedTokens" value="STRING_LITERAL"/>
   <property name="maximumNumber" value="0"/>
   <property name="maximumDepth" value="1"/>
 </module>

To configure the check to produce a violation on an assert statement that may have side effects (formatted for browser display):

 <module name="DescendantToken">
   <property name="tokens" value="LITERAL_ASSERT"/>
   <property name="limitedTokens" value="ASSIGN,DEC,INC,POST_DEC,
     POST_INC,PLUS_ASSIGN,MINUS_ASSIGN,STAR_ASSIGN,DIV_ASSIGN,MOD_ASSIGN,
     BSR_ASSIGN,SR_ASSIGN,SL_ASSIGN,BAND_ASSIGN,BXOR_ASSIGN,BOR_ASSIGN,
     METHOD_CALL"/>
   <property name="maximumNumber" value="0"/>
 </module>

To configure the check to produce a violation on an initializer in for performs no setup (where a while statement could be used instead):

 <module name="DescendantToken">
   <property name="tokens" value="FOR_INIT"/>
   <property name="limitedTokens" value="EXPR"/>
   <property name="minimumNumber" value="1"/>
 </module>

To configure the check to produce a violation on a switch that is nested in another switch:

 <module name="DescendantToken">
   <property name="tokens" value="LITERAL_SWITCH"/>
   <property name="limitedTokens" value="LITERAL_SWITCH"/>
   <property name="maximumNumber" value="0"/>
   <property name="minimumDepth" value="1"/>
 </module>

To configure the check to produce a violation on a return statement from within a catch or finally block:

 <module name="DescendantToken">
   <property name="tokens" value="LITERAL_FINALLY,LITERAL_CATCH"/>
   <property name="limitedTokens" value="LITERAL_RETURN"/>
   <property name="maximumNumber" value="0"/>
 </module>

To configure the check to produce a violation on a try statement within a catch or finally block:

 <module name="DescendantToken">
   <property name="tokens" value="LITERAL_CATCH,LITERAL_FINALLY"/>
   <property name="limitedTokens" value="LITERAL_TRY"/>
   <property name="maximumNumber" value="0"/>
 </module>

To configure the check to produce a violation on a switch with too many cases:

 <module name="DescendantToken">
   <property name="tokens" value="LITERAL_SWITCH"/>
   <property name="limitedTokens" value="LITERAL_CASE"/>
   <property name="maximumDepth" value="2"/>
   <property name="maximumNumber" value="10"/>
 </module>

To configure the check to produce a violation on a method with too many local variables:

 <module name="DescendantToken">
   <property name="tokens" value="METHOD_DEF"/>
   <property name="limitedTokens" value="VARIABLE_DEF"/>
   <property name="maximumDepth" value="2"/>
   <property name="maximumNumber" value="10"/>
 </module>

To configure the check to produce a violation on a method with too many returns:

 <module name="DescendantToken">
   <property name="tokens" value="METHOD_DEF"/>
   <property name="limitedTokens" value="LITERAL_RETURN"/>
   <property name="maximumNumber" value="3"/>
 </module>

To configure the check to produce a violation on an interface with too many fields:

 <module name="DescendantToken">
   <property name="tokens" value="INTERFACE_DEF"/>
   <property name="limitedTokens" value="VARIABLE_DEF"/>
   <property name="maximumDepth" value="2"/>
   <property name="maximumNumber" value="0"/>
 </module>

To configure the check to produce a violation on a method which throws too many exceptions:

 <module name="DescendantToken">
   <property name="tokens" value="LITERAL_THROWS"/>
   <property name="limitedTokens" value="IDENT"/>
   <property name="maximumNumber" value="1"/>
 </module>

To configure the check to produce a violation on a method with too many expressions:

 <module name="DescendantToken">
   <property name="tokens" value="METHOD_DEF"/>
   <property name="limitedTokens" value="EXPR"/>
   <property name="maximumNumber" value="200"/>
 </module>

To configure the check to produce a violation on an empty statement:

 <module name="DescendantToken">
   <property name="tokens" value="EMPTY_STAT"/>
   <property name="limitedTokens" value="EMPTY_STAT"/>
   <property name="maximumNumber" value="0"/>
   <property name="maximumDepth" value="0"/>
   <property name="maximumMessage"
     value="Empty statement is not allowed."/>
 </module>

To configure the check to produce a violation on a class with too many fields:

 <module name="DescendantToken">
   <property name="tokens" value="CLASS_DEF"/>
   <property name="limitedTokens" value="VARIABLE_DEF"/>
   <property name="maximumDepth" value="2"/>
   <property name="maximumNumber" value="10"/>
 </module>

Parent is com.puppycrawl.tools.checkstyle.TreeWalker

Violation Message Keys:

descendant.token.max
descendant.token.min
descendant.token.sum.max
descendant.token.sum.min

Since:: 3.2

Nested Class Summary
- Nested classes/interfaces inherited from class com.puppycrawl.tools.checkstyle.api.AutomaticBean
  AutomaticBean.OutputStreamOptions

Field Summary

Fields
Modifier and Type	Field and Description
`private int[]`	`counts` Counts of descendant tokens.
`private int[]`	`limitedTokens` Specify set of tokens with limited occurrences as descendants.
`private int`	`maximumDepth` Specify the maximum depth for descendant counts.
`private java.lang.String`	`maximumMessage` Define the violation message when the maximum count is exceeded.
`private int`	`maximumNumber` Specify a maximum count for descendants.
`private int`	`minimumDepth` Specify the minimum depth for descendant counts.
`private java.lang.String`	`minimumMessage` Define the violation message when the minimum count is not reached.
`private int`	`minimumNumber` Specify a minimum count for descendants.
`static java.lang.String`	`MSG_KEY_MAX` A key is pointing to the warning message text in "messages.properties" file.
`static java.lang.String`	`MSG_KEY_MIN` A key is pointing to the warning message text in "messages.properties" file.
`static java.lang.String`	`MSG_KEY_SUM_MAX` A key is pointing to the warning message text in "messages.properties" file.
`static java.lang.String`	`MSG_KEY_SUM_MIN` A key is pointing to the warning message text in "messages.properties" file.
`private boolean`	`sumTokenCounts` Control whether the number of tokens found should be calculated from the sum of the individual token counts.

Constructor Summary

Constructors
Constructor and Description

DescendantTokenCheck()

Constructors
Constructor and Description
`DescendantTokenCheck()`

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`private void`	`countTokens(DetailAST ast, int depth)` Counts the number of occurrences of descendant tokens.
`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 void`	`logAsSeparated(DetailAST ast)` Log violations for each Token.
`private void`	`logAsTotal(DetailAST ast)` Log validation as one violation.
`void`	`setLimitedTokens(java.lang.String... limitedTokensParam)` Setter to specify set of tokens with limited occurrences as descendants.
`void`	`setMaximumDepth(int maximumDepth)` Setter to specify the maximum depth for descendant counts.
`void`	`setMaximumMessage(java.lang.String message)` Setter to define the violation message when the maximum count is exceeded.
`void`	`setMaximumNumber(int maximumNumber)` Setter to specify a maximum count for descendants.
`void`	`setMinimumDepth(int minimumDepth)` Setter to specify the minimum depth for descendant counts.
`void`	`setMinimumMessage(java.lang.String message)` Setter to define the violation message when the minimum count is not reached.
`void`	`setMinimumNumber(int minimumNumber)` Setter to specify a minimum count for descendants.
`void`	`setSumTokenCounts(boolean sum)` Setter to control whether the number of tokens found should be calculated from the sum of the individual token counts.
`void`	`visitToken(DetailAST ast)` Called to process a token.

Methods inherited from class com.puppycrawl.tools.checkstyle.api.AbstractCheck
beginTree, clearViolations, destroy, finishTree, getFileContents, 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.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_MIN
```
public static final java.lang.String MSG_KEY_MIN
```
    A key is pointing to the warning message text in "messages.properties" file.
    
    See Also:
    
    Constant Field Values
  - MSG_KEY_MAX
```
public static final java.lang.String MSG_KEY_MAX
```
    A key is pointing to the warning message text in "messages.properties" file.
    
    See Also:
    
    Constant Field Values
  - MSG_KEY_SUM_MIN
```
public static final java.lang.String MSG_KEY_SUM_MIN
```
    A key is pointing to the warning message text in "messages.properties" file.
    
    See Also:
    
    Constant Field Values
  - MSG_KEY_SUM_MAX
```
public static final java.lang.String MSG_KEY_SUM_MAX
```
    A key is pointing to the warning message text in "messages.properties" file.
    
    See Also:
    
    Constant Field Values
  - minimumDepth
```
private int minimumDepth
```
    Specify the minimum depth for descendant counts.
  - maximumDepth
```
private int maximumDepth
```
    Specify the maximum depth for descendant counts.
  - minimumNumber
```
private int minimumNumber
```
    Specify a minimum count for descendants.
  - maximumNumber
```
private int maximumNumber
```
    Specify a maximum count for descendants.
  - sumTokenCounts
```
private boolean sumTokenCounts
```
    Control whether the number of tokens found should be calculated from the sum of the individual token counts.
  - limitedTokens
```
private int[] limitedTokens
```
    Specify set of tokens with limited occurrences as descendants.
  - minimumMessage
```
private java.lang.String minimumMessage
```
    Define the violation message when the minimum count is not reached.
  - maximumMessage
```
private java.lang.String maximumMessage
```
    Define the violation message when the maximum count is exceeded.
  - counts
```
private int[] counts
```
    Counts of descendant tokens. Indexed by (token ID - 1) for performance.
- Constructor Detail
  - DescendantTokenCheck
```
public DescendantTokenCheck()
```
- Method Detail
  - 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
  - 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
  - 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
  - logAsSeparated
```
private void logAsSeparated(DetailAST ast)
```
    Log violations for each Token.
    
    Parameters:
    
    ast - token
  - logAsTotal
```
private void logAsTotal(DetailAST ast)
```
    Log validation as one violation.
    
    Parameters:
    
    ast - current token
  - countTokens
```
private void countTokens(DetailAST ast,
                         int depth)
```
    Counts the number of occurrences of descendant tokens.
    
    Parameters:
    
    ast - the root token for descendants.
    
    depth - the maximum depth of the counted descendants.
  - setLimitedTokens
```
public void setLimitedTokens(java.lang.String... limitedTokensParam)
```
    Setter to specify set of tokens with limited occurrences as descendants.
    
    Parameters:
    
    limitedTokensParam - - list of tokens to ignore.
  - setMinimumDepth
```
public void setMinimumDepth(int minimumDepth)
```
    Setter to specify the minimum depth for descendant counts.
    
    Parameters:
    
    minimumDepth - the minimum depth for descendant counts.
  - setMaximumDepth
```
public void setMaximumDepth(int maximumDepth)
```
    Setter to specify the maximum depth for descendant counts.
    
    Parameters:
    
    maximumDepth - the maximum depth for descendant counts.
  - setMinimumNumber
```
public void setMinimumNumber(int minimumNumber)
```
    Setter to specify a minimum count for descendants.
    
    Parameters:
    
    minimumNumber - the minimum count for descendants.
  - setMaximumNumber
```
public void setMaximumNumber(int maximumNumber)
```
    Setter to specify a maximum count for descendants.
    
    Parameters:
    
    maximumNumber - the maximum count for descendants.
  - setMinimumMessage
```
public void setMinimumMessage(java.lang.String message)
```
    Setter to define the violation message when the minimum count is not reached.
    Parameters:
    message - the violation message for minimum count not reached. Used as a MessageFormat pattern with arguments
    
    {0} - token count
    
    {1} - minimum number
    
    {2} - name of token
    
    {3} - name of limited token
  - setMaximumMessage
```
public void setMaximumMessage(java.lang.String message)
```
    Setter to define the violation message when the maximum count is exceeded.
    Parameters:
    message - the violation message for maximum count exceeded. Used as a MessageFormat pattern with arguments
    
    {0} - token count
    
    {1} - maximum number
    
    {2} - name of token
    
    {3} - name of limited token
  - setSumTokenCounts
```
public void setSumTokenCounts(boolean sum)
```
    Setter to control whether the number of tokens found should be calculated from the sum of the individual token counts.
    
    Parameters:
    
    sum - whether to use the sum.

Class DescendantTokenCheck

Nested Class Summary

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

Field Summary

Constructor Summary

Method Summary

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

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

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

Methods inherited from class java.lang.Object

Field Detail

MSG_KEY_MIN

MSG_KEY_MAX

MSG_KEY_SUM_MIN

MSG_KEY_SUM_MAX

minimumDepth

maximumDepth

minimumNumber

maximumNumber

sumTokenCounts

limitedTokens

minimumMessage

maximumMessage

counts

Constructor Detail

DescendantTokenCheck

Method Detail

getAcceptableTokens

getDefaultTokens

getRequiredTokens

visitToken

logAsSeparated

logAsTotal

countTokens

setLimitedTokens

setMinimumDepth

setMaximumDepth

setMinimumNumber

setMaximumNumber

setMinimumMessage

setMaximumMessage

setSumTokenCounts