com.puppycrawl.tools.checkstyle.checks.imports

Class CustomImportOrderCheck

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.imports.CustomImportOrderCheck

All Implemented Interfaces:

Configurable, Contextualizable

public class CustomImportOrderCheck
extends AbstractCheck

Checks that the groups of import declarations appear in the order specified by the user. If there is an import but its group is not specified in the configuration such an import should be placed at the end of the import list.

The rule consists of:

1. STATIC group. This group sets the ordering of static imports.

2. SAME_PACKAGE(n) group. This group sets the ordering of the same package imports. Imports are considered on SAME_PACKAGE group if n first domains in package name and import name are identical.

package java.util.concurrent.locks;

import java.io.File;
import java.util.*; //#1
import java.util.List; //#2
import java.util.StringTokenizer; //#3
import java.util.concurrent.*; //#4
import java.util.concurrent.AbstractExecutorService; //#5
import java.util.concurrent.locks.LockSupport; //#6
import java.util.regex.Pattern; //#7
import java.util.regex.Matcher; //#8

 

If we have SAME_PACKAGE(3) on configuration file, imports #4-6 will be considered as a SAME_PACKAGE group (java.util.concurrent.*, java.util.concurrent.AbstractExecutorService, java.util.concurrent.locks.LockSupport). SAME_PACKAGE(2) will include #1-8. SAME_PACKAGE(4) will include only #6. SAME_PACKAGE(5) will result in no imports assigned to SAME_PACKAGE group because actual package java.util.concurrent.locks has only 4 domains.

3. THIRD_PARTY_PACKAGE group. This group sets ordering of third party imports. Third party imports are all imports except STATIC, SAME_PACKAGE(n), STANDARD_JAVA_PACKAGE and SPECIAL_IMPORTS.

4. STANDARD_JAVA_PACKAGE group. By default this group sets ordering of standard java/javax imports.

5. SPECIAL_IMPORTS group. This group may contains some imports that have particular meaning for the user.

NOTE!

Use the separator '###' between rules.

To set RegExps for THIRD_PARTY_PACKAGE and STANDARD_JAVA_PACKAGE groups use thirdPartyPackageRegExp and standardPackageRegExp options.

Pretty often one import can match more than one group. For example, static import from standard package or regular expressions are configured to allow one import match multiple groups. In this case, group will be assigned according to priorities:

1. STATIC has top priority
2. SAME_PACKAGE has second priority
3. STANDARD_JAVA_PACKAGE and SPECIAL_IMPORTS will compete using "best match" rule: longer matching substring wins; in case of the same length, lower position of matching substring wins; if position is the same, order of rules in configuration solves the puzzle.
4. THIRD_PARTY has the least priority

Few examples to illustrate "best match":

1. patterns STANDARD_JAVA_PACKAGE = "Check", SPECIAL_IMPORTS="ImportOrderCheck" and input file:

import com.puppycrawl.tools.checkstyle.checks.imports.CustomImportOrderCheck;
import com.puppycrawl.tools.checkstyle.checks.imports.ImportOrderCheck;
 

Result: imports will be assigned to SPECIAL_IMPORTS, because matching substring length is 16. Matching substring for STANDARD_JAVA_PACKAGE is 5.

2. patterns STANDARD_JAVA_PACKAGE = "Check", SPECIAL_IMPORTS="Avoid" and file:

import com.puppycrawl.tools.checkstyle.checks.imports.AvoidStarImportCheck;
 

Result: import will be assigned to SPECIAL_IMPORTS. Matching substring length is 5 for both patterns. However, "Avoid" position is lower then "Check" position.

    Properties:
 

name	Description	type	default value
customImportOrderRules	List of order declaration customizing by user.	string	null
standardPackageRegExp	RegExp for STANDARD_JAVA_PACKAGE group imports.	regular expression	^(java|javax)\.
thirdPartyPackageRegExp	RegExp for THIRD_PARTY_PACKAGE group imports.	regular expression	.*
specialImportsRegExp	RegExp for SPECIAL_IMPORTS group imports.	regular expression	^$
separateLineBetweenGroups	Force empty line separator between import groups.	boolean	true
sortImportsInGroupAlphabetically	Force grouping alphabetically, in ASCII sort order.	boolean	false

For example:

To configure the check so that it matches default Eclipse formatter configuration (tested on Kepler, Luna and Mars):

• group of static imports is on the top
• groups of non-static imports: "java" and "javax" packages first, then "org" and then all other imports
• imports will be sorted in the groups
• groups are separated by, at least, one blank line

 <module name="CustomImportOrder">
    <property name="customImportOrderRules"
        value="STATIC###STANDARD_JAVA_PACKAGE###SPECIAL_IMPORTS"/>
    <property name="specialImportsRegExp" value="org"/>
    <property name="sortImportsInGroupAlphabetically" value="true"/>
    <property name="separateLineBetweenGroups" value="true"/>
 </module>
 

To configure the check so that it matches default IntelliJ IDEA formatter configuration (tested on v14):

• group of static imports is on the bottom
• groups of non-static imports: all imports except of "javax" and "java", then "javax" and "java"
• imports will be sorted in the groups
• groups are separated by, at least, one blank line

Note: "separated" option is disabled because IDEA default has blank line between "java" and static imports, and no blank line between "javax" and "java"

 <module name="CustomImportOrder">
    <property name="customImportOrderRules"
        value="THIRD_PARTY_PACKAGE###SPECIAL_IMPORTS###STANDARD_JAVA_PACKAGE
        ###STATIC"/>
    <property name="specialImportsRegExp" value="^javax\."/>
    <property name="standardPackageRegExp" value="^java\."/>
    <property name="sortImportsInGroupAlphabetically" value="true"/>
    <property name="separateLineBetweenGroups" value="false"/>
</module>
 

To configure the check so that it matches default NetBeans formatter configuration (tested on v8):

• groups of non-static imports are not defined, all imports will be sorted as a one group
• static imports are not separated, they will be sorted along with other imports

<module name="CustomImportOrder"/>
 

To set RegExps for THIRD_PARTY_PACKAGE and STANDARD_JAVA_PACKAGE groups use thirdPartyPackageRegExp and standardPackageRegExp options.

 <module name="CustomImportOrder">
    <property name="customImportOrderRules"
    value="STATIC###SAME_PACKAGE(3)###THIRD_PARTY_PACKAGE###STANDARD_JAVA_PACKAGE"/>
    <property name="thirdPartyPackageRegExp" value="com|org"/>
    <property name="standardPackageRegExp" value="^(java|javax)\."/>
 </module>
 

Also, this check can be configured to force empty line separator between import groups. For example

 <module name="CustomImportOrder">
    <property name="separateLineBetweenGroups" value="true"/>
 </module>
 

It is possible to enforce ASCII sort order of imports in groups using the following configuration:

 <module name="CustomImportOrder">
    <property name="sortImportsInGroupAlphabetically" value="true"/>
 </module>
 

Example of ASCII order:

 
import java.awt.Dialog;
import java.awt.Window;
import java.awt.color.ColorSpace;
import java.awt.Frame; // violation here - in ASCII order 'F' should go before 'c',
                       // as all uppercase come before lowercase letters
 

To force checking imports sequence such as:

 
 package com.puppycrawl.tools.checkstyle.imports;

 import com.google.common.annotations.GwtCompatible;
 import com.google.common.annotations.Beta;
 import com.google.common.annotations.VisibleForTesting;

 import org.abego.treelayout.Configuration;

 import static sun.tools.util.ModifierFilter.ALL_ACCESS;

 import com.google.common.annotations.GwtCompatible; // violation here - should be in the
                                                     // THIRD_PARTY_PACKAGE group
 import android.*;
 

configure as follows:

 <module name="CustomImportOrder">
    <property name="customImportOrderRules"
    value="SAME_PACKAGE(3)###THIRD_PARTY_PACKAGE###STATIC###SPECIAL_IMPORTS"/>
    <property name="specialImportsRegExp" value="android.*"/>
 </module>
 

Author:

maxvetrenko, Aleksey Nesterenko

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
static String	MSG_LEX A key is pointing to the warning message text in "messages.properties" file.
static String	MSG_LINE_SEPARATOR A key is pointing to the warning message text in "messages.properties" file.
static String	MSG_NONGROUP_EXPECTED A key is pointing to the warning message text in "messages.properties" file.
static String	MSG_NONGROUP_IMPORT A key is pointing to the warning message text in "messages.properties" file.
static String	MSG_ORDER A key is pointing to the warning message text in "messages.properties" file.
static String	SAME_PACKAGE_RULE_GROUP SAME_PACKAGE group name.
static String	SPECIAL_IMPORTS_RULE_GROUP SPECIAL_IMPORTS group name.
static String	STANDARD_JAVA_PACKAGE_RULE_GROUP STANDARD_JAVA_PACKAGE group name.
static String	STATIC_RULE_GROUP STATIC group name.
static String	THIRD_PARTY_PACKAGE_RULE_GROUP THIRD_PARTY_PACKAGE group name.

Constructor Summary

Constructors

Constructor and Description
CustomImportOrderCheck()

Method Summary

Modifier and Type	Method and Description
void	beginTree(DetailAST rootAST) Called before the starting to process a tree.
void	finishTree(DetailAST rootAST) Called after finished processing a tree.
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.
void	setCustomImportOrderRules(String inputCustomImportOrder) Sets a custom import order from the rules in the string format specified by user.
void	setSeparateLineBetweenGroups(boolean value) Sets separateLineBetweenGroups specified by user.
void	setSortImportsInGroupAlphabetically(boolean value) Sets sortImportsInGroupAlphabetically specified by user.
void	setSpecialImportsRegExp(Pattern regexp) Sets specialImportsRegExp specified by user.
void	setStandardPackageRegExp(Pattern regexp) Sets standardRegExp specified by user.
void	setThirdPartyPackageRegExp(Pattern regexp) Sets thirdPartyRegExp specified by user.
void	visitToken(DetailAST ast) Called to process a token.

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

clearMessages, destroy, getClassLoader, getFileContents, getLine, getLines, getMessages, getTabWidth, getTokenNames, init, isCommentNodesRequired, leaveToken, log, log, log, setClassLoader, 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_LINE_SEPARATOR

public static final String MSG_LINE_SEPARATOR

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

See Also:

Constant Field Values

MSG_LEX

public static final String MSG_LEX

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

See Also:

Constant Field Values

MSG_NONGROUP_IMPORT

public static final String MSG_NONGROUP_IMPORT

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

See Also:

Constant Field Values

MSG_NONGROUP_EXPECTED

public static final String MSG_NONGROUP_EXPECTED

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

See Also:

Constant Field Values

MSG_ORDER

public static final String MSG_ORDER

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

See Also:

Constant Field Values

STATIC_RULE_GROUP

public static final String STATIC_RULE_GROUP

STATIC group name.

See Also:

Constant Field Values

SAME_PACKAGE_RULE_GROUP

public static final String SAME_PACKAGE_RULE_GROUP

SAME_PACKAGE group name.

See Also:

Constant Field Values

THIRD_PARTY_PACKAGE_RULE_GROUP

public static final String THIRD_PARTY_PACKAGE_RULE_GROUP

THIRD_PARTY_PACKAGE group name.

See Also:

Constant Field Values

STANDARD_JAVA_PACKAGE_RULE_GROUP

public static final String STANDARD_JAVA_PACKAGE_RULE_GROUP

STANDARD_JAVA_PACKAGE group name.

See Also:

Constant Field Values

SPECIAL_IMPORTS_RULE_GROUP

public static final String SPECIAL_IMPORTS_RULE_GROUP

SPECIAL_IMPORTS group name.

See Also:

Constant Field Values

Constructor Detail

CustomImportOrderCheck

public CustomImportOrderCheck()

Method Detail

setStandardPackageRegExp

public final void setStandardPackageRegExp(Pattern regexp)

Sets standardRegExp specified by user.

Parameters:

regexp - user value.

setThirdPartyPackageRegExp

public final void setThirdPartyPackageRegExp(Pattern regexp)

Sets thirdPartyRegExp specified by user.

Parameters:

regexp - user value.

setSpecialImportsRegExp

public final void setSpecialImportsRegExp(Pattern regexp)

Sets specialImportsRegExp specified by user.

Parameters:

regexp - user value.

setSeparateLineBetweenGroups

public final void setSeparateLineBetweenGroups(boolean value)

Sets separateLineBetweenGroups specified by user.

Parameters:

value - user value.

setSortImportsInGroupAlphabetically

public final void setSortImportsInGroupAlphabetically(boolean value)

Sets sortImportsInGroupAlphabetically specified by user.

Parameters:

value - user value.

setCustomImportOrderRules

public final void setCustomImportOrderRules(String inputCustomImportOrder)

Sets a custom import order from the rules in the string format specified by user.

Parameters:

inputCustomImportOrder - user value.

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

beginTree

public void beginTree(DetailAST rootAST)

Description copied from class: AbstractCheck

Called before the starting to process a tree. Ideal place to initialize information that is to be collected whilst processing a tree.

Overrides:

beginTree in class AbstractCheck

Parameters:

rootAST - the root of the tree

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

finishTree

public void finishTree(DetailAST rootAST)

Description copied from class: AbstractCheck

Called after finished processing a tree. Ideal place to report on information collected whilst processing a tree.

Overrides:

finishTree in class AbstractCheck

Parameters:

rootAST - the root of the tree