com.github.sevntu.checkstyle.checks.coding

Class MapIterationInForEachLoopCheck

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.MapIterationInForEachLoopCheck

All Implemented Interfaces:

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

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

This check can help you to write the whole for-each map iteration more correctly.

1. If you iterate over a map using map.keySet() or map.entrySet(), but your code uses only map values, Check will propose you to use map.values() instead of map.keySet() or map.entrySet(). Replacing map.keySet() or map.entrySet() with map.values() for such cases can a bit improve an iteration performance.

Bad:

 for (Map.Entry<String, String> entry : map.entrySet())
 {
     System.out.println(entry.getValue());
 }
 

 for (String key : map.keySet())
 {
     System.out.println(map.get(key));
 }
 

Good:

 for (String value : map.values())
 {
     System.out.println(value);
 }
 

2. If you iterate over a map using map.entrySet(), but never call entry.getValue(), Check will propose you to use map.keySet() instead of map.entrySet(). to iterate over map keys only.

Bad:

 for (Map.Entry<String, String> entry : map.entrySet())
 {
     System.out.println(entry.getKey());
 }
 

Good:

 for (String key : map.keySet())
 {
     System.out.println(key);
 }
 

3. If you iterate over a map with map.keySet() and use both keys and values, check will propose you to use map.entrySet() to improve an iteration performance by avoiding search operations inside a map. For this case, iteration can significantly grow up a performance.

Bad:

 for (String key : map.keySet())
 {
     System.out.println(key + "  " + map.get(key));
 }
 

Good:

 for (Map.Entry<String, String>S entry : map.entrySet())
 {
     System.out.println(entry.getValue() + "   " + entry.getKey());
 }
 

Since:

1.11.0

Author:

Max Vetrenko

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_ENTRYSET The key is pointing to the warning message text in "messages.properties" file.
static String	MSG_KEY_KEYSET The key is pointing to the warning message text in "messages.properties" file.
static String	MSG_KEY_VALUES The key is pointing to the warning message text in "messages.properties" file.

Constructor Summary

Constructors

Constructor and Description
MapIterationInForEachLoopCheck() Creates default importList and mapImportClassesNamesList.

Method Summary

Modifier and Type	Method and Description
void	beginTree(com.puppycrawl.tools.checkstyle.api.DetailAST ast)
int[]	getAcceptableTokens()
int[]	getDefaultTokens()
int[]	getRequiredTokens()
void	setProposeEntrySetUsage(boolean proposeEntrySetUsage) Set aProcessingEntrySet.
void	setProposeKeySetUsage(boolean proposeKeySetUsage) Set aProcessingKeySet.
void	setProposeValuesUsage(boolean proposeValuesUsage) Set aProcessingValue.
void	setSupportedMapImplQualifiedNames(String... setSupportedMapImplQualifiedNames) Set user's map implementations.
void	visitToken(com.puppycrawl.tools.checkstyle.api.DetailAST ast)

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

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_KEYSET

public static final String MSG_KEY_KEYSET

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

See Also:

Constant Field Values

MSG_KEY_ENTRYSET

public static final String MSG_KEY_ENTRYSET

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

See Also:

Constant Field Values

MSG_KEY_VALUES

public static final String MSG_KEY_VALUES

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

See Also:

Constant Field Values

Constructor Detail

MapIterationInForEachLoopCheck

public MapIterationInForEachLoopCheck()

Creates default importList and mapImportClassesNamesList.

Method Detail

setSupportedMapImplQualifiedNames

public final void setSupportedMapImplQualifiedNames(String... setSupportedMapImplQualifiedNames)

Set user's map implementations. It must state the full paths of imported classes. Import paths must be separated by commas. For example: java.util.Map, java.util.HashMap.

Parameters:

setSupportedMapImplQualifiedNames - User's set of map implementations.

setProposeValuesUsage

public void setProposeValuesUsage(boolean proposeValuesUsage)

Set aProcessingValue. If value is true, Check will process cases, where values() method will be suitable.

Parameters:

proposeValuesUsage - User's value of mProcessingValue.

setProposeKeySetUsage

public void setProposeKeySetUsage(boolean proposeKeySetUsage)

Set aProcessingKeySet. If value is true, Check will process cases, where keySet() method will be suitable.

Parameters:

proposeKeySetUsage - User's value of mIsCheckKeySetProcessingEnabled.

setProposeEntrySetUsage

public void setProposeEntrySetUsage(boolean proposeEntrySetUsage)

Set aProcessingEntrySet. If value is true, Check will process cases, where entrySet() method will be suitable.

Parameters:

proposeEntrySetUsage - User's value of mIsCheckEntrySetProcessingEnabled.

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

beginTree

public void beginTree(com.puppycrawl.tools.checkstyle.api.DetailAST ast)

Overrides:

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

visitToken

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

Overrides:

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