From fd50c7c636e2c8456d540ad54e4899342143ef9a Mon Sep 17 00:00:00 2001
From: Vova Kolmakov <wombatukun@apache.org>
Date: Wed, 22 Apr 2026 13:42:31 +0700
Subject: [PATCH] build: add spotless, checkstyle, and enforcer plugin
 configuration

---
 .editorconfig  |  19 ++++++
 checkstyle.xml | 174 +++++++++++++++++++++++++++++++++++++++++++++++++
 pom.xml        |  90 +++++++++++++++++++++++++
 3 files changed, 283 insertions(+)
 create mode 100644 .editorconfig
 create mode 100644 checkstyle.xml

diff --git a/.editorconfig b/.editorconfig
new file mode 100644
index 0000000..0a2a8e1
--- /dev/null
+++ b/.editorconfig
@@ -0,0 +1,19 @@
+root = true
+
+[*]
+charset = utf-8
+end_of_line = lf
+insert_final_newline = true
+trim_trailing_whitespace = true
+
+[*.java]
+indent_style = space
+indent_size = 4
+max_line_length = 100
+
+[*.{xml,yml,yaml}]
+indent_style = space
+indent_size = 2
+
+[Makefile]
+indent_style = tab
diff --git a/checkstyle.xml b/checkstyle.xml
new file mode 100644
index 0000000..a689896
--- /dev/null
+++ b/checkstyle.xml
@@ -0,0 +1,174 @@
+<!--
+  ~ Licensed to the Apache Software Foundation (ASF) under one or more
+  ~ contributor license agreements.  See the NOTICE file distributed with
+  ~ this work for additional information regarding copyright ownership.
+  ~ The ASF licenses this file to You under the Apache License, Version 2.0
+  ~ (the "License"); you may not use this file except in compliance with
+  ~ the License.  You may obtain a copy of the License at
+  ~
+  ~    http://www.apache.org/licenses/LICENSE-2.0
+  ~
+  ~ Unless required by applicable law or agreed to in writing, software
+  ~ distributed under the License is distributed on an "AS IS" BASIS,
+  ~ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  ~ See the License for the specific language governing permissions and
+  ~ limitations under the License.
+  -->
+
+<!DOCTYPE module PUBLIC
+        "-//Puppy Crawl//DTD Check Configuration 1.3//EN"
+        "https://checkstyle.org/dtds/configuration_1_3.dtd">
+
+<module name = "Checker">
+    <property name="charset" value="UTF-8"/>
+
+    <property name="severity" value="error"/>
+
+    <property name="fileExtensions" value="java, properties, xml"/>
+
+    <!-- Checks for whitespace                               -->
+    <!-- See http://checkstyle.sf.net/config_whitespace.html -->
+    <module name="FileTabCharacter">
+        <property name="eachLine" value="true"/>
+    </module>
+
+    <module name="RegexpSingleline">
+        <!-- \s matches whitespace character, $ matches end of line. -->
+        <property name="format" value="\s+$"/>
+        <property name="message" value="No trailing whitespace allowed."/>
+    </module>
+
+    <module name="LineLength">
+        <property name="max" value="100"/>
+        <property name="ignorePattern" value="^package.*|^import.*|a href|href|http://|https://|ftp://"/>
+    </module>
+
+    <module name="TreeWalker">
+        <!--
+        If you wish to turn off checking for a section of code, you can put a comment in the source
+        before and after the section, with the following syntax:
+
+          // checkstyle.off: XXX (such as checkstyle.off: NoFinalizer)
+          ...  // stuff that breaks the styles
+          // checkstyle.on: XXX (such as checkstyle.on: NoFinalizer)
+        -->
+        <module name="SuppressionCommentFilter">
+            <property name="offCommentFormat" value="checkstyle\.off\: ([\w\|]+)"/>
+            <property name="onCommentFormat" value="checkstyle\.on\: ([\w\|]+)"/>
+            <property name="checkFormat" value="$1"/>
+        </module>
+        <module name="OuterTypeFilename"/>
+        <module name="IllegalTokenText">
+            <property name="tokens" value="STRING_LITERAL, CHAR_LITERAL"/>
+            <property name="format" value="\\u00(08|09|0(a|A)|0(c|C)|0(d|D)|22|27|5(C|c))|\\(0(10|11|12|14|15|42|47)|134)"/>
+            <property name="message" value="Avoid using corresponding octal or Unicode escape."/>
+        </module>
+        <module name="AvoidEscapedUnicodeCharacters">
+            <property name="allowEscapesForControlCharacters" value="true"/>
+            <property name="allowByTailComment" value="true"/>
+            <property name="allowNonPrintableEscapes" value="true"/>
+        </module>
+        <module name="NoLineWrap"/>
+        <module name="EmptyBlock">
+            <property name="option" value="TEXT"/>
+            <property name="tokens" value="LITERAL_TRY, LITERAL_FINALLY, LITERAL_IF, LITERAL_ELSE, LITERAL_SWITCH"/>
+        </module>
+        <module name="NeedBraces">
+            <property name="allowSingleLineStatement" value="true"/>
+        </module>
+        <module name="OneStatementPerLine"/>
+        <module name="ArrayTypeStyle"/>
+        <module name="FallThrough"/>
+        <module name="UpperEll"/>
+        <module name="ModifierOrder"/>
+        <module name="SeparatorWrap">
+            <property name="tokens" value="DOT"/>
+            <property name="option" value="nl"/>
+        </module>
+        <module name="SeparatorWrap">
+            <property name="tokens" value="COMMA"/>
+            <property name="option" value="EOL"/>
+        </module>
+        <module name="PackageName">
+            <property name="format" value="^[a-z]+(\.[a-z][a-z0-9]*)*$"/>
+            <message key="name.invalidPattern"
+                     value="Package name ''{0}'' must match pattern ''{1}''."/>
+        </module>
+        <module name="ClassTypeParameterName">
+            <property name="format" value="([A-Z][a-zA-Z0-9]*$)"/>
+            <message key="name.invalidPattern"
+                     value="Class type name ''{0}'' must match pattern ''{1}''."/>
+        </module>
+        <module name="MethodTypeParameterName">
+            <property name="format" value="([A-Z][a-zA-Z0-9]*)"/>
+            <message key="name.invalidPattern"
+                     value="Method type name ''{0}'' must match pattern ''{1}''."/>
+        </module>
+        <module name="GenericWhitespace">
+            <message key="ws.followed"
+                     value="GenericWhitespace ''{0}'' is followed by whitespace."/>
+            <message key="ws.preceded"
+                     value="GenericWhitespace ''{0}'' is preceded with whitespace."/>
+            <message key="ws.illegalFollow"
+                     value="GenericWhitespace ''{0}'' should followed by whitespace."/>
+            <message key="ws.notPreceded"
+                     value="GenericWhitespace ''{0}'' is not preceded with whitespace."/>
+        </module>
+        <module name="MethodParamPad"/>
+        <module name="AnnotationLocation">
+            <property name="tokens" value="CLASS_DEF, INTERFACE_DEF, ENUM_DEF, METHOD_DEF, CTOR_DEF"/>
+        </module>
+        <module name="AnnotationLocation">
+            <property name="tokens" value="VARIABLE_DEF"/>
+            <property name="allowSamelineMultipleAnnotations" value="true"/>
+        </module>
+        <module name="MethodName">
+            <property name="format" value="^[a-z][a-z0-9][a-zA-Z0-9_]*$"/>
+            <message key="name.invalidPattern"
+                     value="Method name ''{0}'' must match pattern ''{1}''."/>
+        </module>
+        <module name="EmptyCatchBlock">
+            <property name="exceptionVariableName" value="expected"/>
+        </module>
+        <module name="CommentsIndentation"/>
+        <module name="UnusedImports"/>
+        <module name="RedundantImport"/>
+        <module name="RedundantModifier"/>
+        <module name="RegexpSinglelineJava">
+            <property name="format" value="throw new \w+Error\("/>
+            <property name="message" value="Avoid throwing error in application code."/>
+        </module>
+        <module name="RegexpSinglelineJava">
+            <property name="format" value="Objects\.toStringHelper"/>
+            <property name="message" value="Avoid using Object.toStringHelper. Use ToStringBuilder instead." />
+        </module>
+        <module name="RegexpSinglelineJava">
+            <property name="format" value="new (java\.lang\.)?(Byte|Integer|Long|Short)\("/>
+            <property name="message" value="Use static factory 'valueOf' or 'parseXXX' instead of the deprecated constructors." />
+        </module>
+        <module name="RegexpSinglelineJava">
+            <property name="format" value="Files\.createTempDir\("/>
+            <property name="message"
+                      value="Avoid using com.google.common.io.Files.createTempDir() due to CVE-2020-8908. Use java.nio.file.Files.createTempDirectory() instead." />
+        </module>
+        <module name="RegexpSinglelineJava">
+            <property name="format" value="FileBackedOutputStream"/>
+            <property name="message" value="Avoid using FileBackedOutputStream due to CVE-2023-2976." />
+        </module>
+        <module name="RegexpSinglelineJava">
+            <property name="format" value="AtomicDoubleArray"/>
+            <property name="message" value="Avoid using AtomicDoubleArray due to CVE-2018-10237." />
+        </module>
+        <module name="RegexpSinglelineJava">
+            <property name="format" value="CompoundOrdering"/>
+            <property name="message" value="Avoid using CompoundOrdering due to CVE-2018-10237." />
+        </module>
+        <module name="RegexpSinglelineJava">
+            <property name="format" value="@Test\(expected"/>
+            <property name="message" value="Please use the `assertThrows` method to test for exceptions." />
+        </module>
+        <module name="IllegalImport">
+            <property name="illegalPkgs" value="org.apache.log4j,org.apache.commons.lang" />
+        </module>
+    </module>
+</module>
diff --git a/pom.xml b/pom.xml
index d78486c..23f5df6 100644
--- a/pom.xml
+++ b/pom.xml
@@ -27,6 +27,28 @@
         <log4j.version>2.20.0</log4j.version>
         <mockito.version>5.3.1</mockito.version>
         <assertj.version>3.24.2</assertj.version>
+
+        <!-- Code style tooling -->
+        <spotless.version>2.43.0</spotless.version>
+        <spotless.java.googlejavaformat.version>1.19.2</spotless.java.googlejavaformat.version>
+        <spotless.delimiter>package</spotless.delimiter>
+        <spotless.license.header>
+            /*
+            * Licensed under the Apache License, Version 2.0 (the "License");
+            * you may not use this file except in compliance with the License.
+            * You may obtain a copy of the License at
+            *
+            *     http://www.apache.org/licenses/LICENSE-2.0
+            *
+            * Unless required by applicable law or agreed to in writing, software
+            * distributed under the License is distributed on an "AS IS" BASIS,
+            * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+            * See the License for the specific language governing permissions and
+            * limitations under the License.
+            */
+        </spotless.license.header>
+        <maven-checkstyle-plugin.version>3.3.1</maven-checkstyle-plugin.version>
+        <maven-enforcer-plugin.version>3.4.1</maven-enforcer-plugin.version>
     </properties>
 
     <dependencies>
@@ -345,6 +367,74 @@
                     </execution>
                 </executions>
             </plugin>
+
+            <!-- Spotless code formatter (invoked explicitly: mvn spotless:check / spotless:apply) -->
+            <plugin>
+                <groupId>com.diffplug.spotless</groupId>
+                <artifactId>spotless-maven-plugin</artifactId>
+                <version>${spotless.version}</version>
+                <configuration>
+                    <upToDateChecking>
+                        <enabled>true</enabled>
+                    </upToDateChecking>
+                    <java>
+                        <includes>
+                            <include>src/main/java/**/*.java</include>
+                            <include>src/test/java/**/*.java</include>
+                        </includes>
+                        <googleJavaFormat>
+                            <version>${spotless.java.googlejavaformat.version}</version>
+                            <style>GOOGLE</style>
+                        </googleJavaFormat>
+                        <importOrder>
+                            <order>org.apache.flink,,javax,java,\#</order>
+                        </importOrder>
+                        <removeUnusedImports/>
+                    </java>
+                    <licenseHeader>
+                        <content>${spotless.license.header}</content>
+                        <delimiter>${spotless.delimiter}</delimiter>
+                    </licenseHeader>
+                </configuration>
+            </plugin>
+
+            <!-- Checkstyle (invoked explicitly: mvn checkstyle:check) -->
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-checkstyle-plugin</artifactId>
+                <version>${maven-checkstyle-plugin.version}</version>
+                <configuration>
+                    <configLocation>checkstyle.xml</configLocation>
+                    <consoleOutput>true</consoleOutput>
+                    <failsOnError>true</failsOnError>
+                    <violationSeverity>warning</violationSeverity>
+                    <linkXRef>false</linkXRef>
+                </configuration>
+            </plugin>
+
+            <!-- Enforcer: Maven version + ban duplicate dependency versions -->
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-enforcer-plugin</artifactId>
+                <version>${maven-enforcer-plugin.version}</version>
+                <executions>
+                    <execution>
+                        <id>enforce-versions</id>
+                        <phase>validate</phase>
+                        <goals>
+                            <goal>enforce</goal>
+                        </goals>
+                        <configuration>
+                            <rules>
+                                <requireMavenVersion>
+                                    <version>3.6.3</version>
+                                </requireMavenVersion>
+                                <banDuplicatePomDependencyVersions/>
+                            </rules>
+                        </configuration>
+                    </execution>
+                </executions>
+            </plugin>
         </plugins>
     </build>