add workflow, checkstyle and configurations

.github/workflows/checkstyle.yml

@@ -0,0 +1,54 @@
+name: Checkstyle
+on: 
+
+  pull_request:
+    branches: ["master", "develop"]
+    paths:
+      - '**/*.java'  # Monitor all Java files
+
+jobs:
+  checkstyle:
+    runs-on: ubuntu-latest
+    permissions: # Add permissions for check enforcement
+      contents: read
+      pull-requests: write
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0  # Required to get changed files
+
+      - name: Set up JDK 17
+        uses: actions/setup-java@v4
+        with:
+          java-version: '17'
+          distribution: 'adopt'
+
+      - name: Get Changed Files
+        id: changed-files
+        uses: tj-actions/changed-files@v39
+        with:
+          files: '**/*.java'
+
+      - name: Cache Maven packages
+        uses: actions/cache@v4
+        with:
+          path: ~/.m2/repository
+          key: ${{ runner.os }}-maven-${{ hashFiles('/pom.xml') }}
+          restore-keys: ${{ runner.os }}-maven
+
+      - name: Install Dependencies
+        run: mvn install -DskipTests
+
+      - name: Run Checkstyle on Changed Files
+        if: steps.changed-files.outputs.any_changed == 'true'
+        run: |
+         mvn checkstyle:check -Dcheckstyle.includes="${{ steps.changed-files.outputs}}"
+
+      - name: Block PR on Checkstyle Failure
+        if: failure()
+        uses: actions/github-script@v7
+        with:
+          script: |
+            core.setFailed('Checkstyle checks failed. Please fix the code formatting issues.')

checkstyle.xml

@@ -0,0 +1,67 @@
+<?xml version="1.0"?>
+<!DOCTYPE module PUBLIC
+          "-//Checkstyle//DTD Checkstyle Configuration 1.3//EN"
+          "https://checkstyle.org/dtds/configuration_1_3.dtd">
+
+<module name="Checker">
+    <property name="severity" value="warning"/>
+    <property name="fileExtensions" value="java"/>
+
+    <!-- Checks for Size Violations -->
+    <module name="FileLength">
+        <property name="max" value="500"/>
+    </module>
+    <module name="LineLength">
+        <property name="max" value="120"/>
+    </module>
+
+    <module name="TreeWalker">
+        <!-- Checks for Naming Conventions -->
+        <module name="MethodName"/>
+        <module name="PackageName"/>
+        <module name="TypeName"/>
+        <module name="ParameterName"/>
+        <module name="LocalVariableName"/>
+        <module name="MemberName"/>
+
+        <!-- Checks for imports -->
+        <module name="AvoidStarImport"/>
+        <module name="IllegalImport"/>
+        <module name="RedundantImport"/>
+        <module name="UnusedImports"/>
+
+        <!-- Checks for Size Violations -->
+        <module name="MethodLength">
+            <property name="max" value="50"/>
+        </module>
+
+        <!-- Checks for whitespace -->
+        <module name="EmptyLineSeparator"/>
+        <module name="GenericWhitespace"/>
+        <module name="MethodParamPad"/>
+        <module name="NoWhitespaceAfter"/>
+        <module name="NoWhitespaceBefore"/>
+        <module name="ParenPad"/>
+        <module name="TypecastParenPad"/>
+        <module name="WhitespaceAfter"/>
+        <module name="WhitespaceAround"/>
+
+        <!-- Modifier Checks -->
+        <module name="ModifierOrder"/>
+        <module name="RedundantModifier"/>
+
+        <!-- Checks for blocks -->
+        <module name="EmptyBlock"/>
+        <module name="LeftCurly"/>
+        <module name="RightCurly"/>
+        <module name="NeedBraces"/>
+
+        <!-- Checks for common coding problems -->
+        <module name="EmptyStatement"/>
+        <module name="EqualsHashCode"/>
+        <module name="IllegalInstantiation"/>
+        <module name="MissingSwitchDefault"/>
+        <module name="SimplifyBooleanExpression"/>
+        <module name="SimplifyBooleanReturn"/>
+    </module>
+</module>

pom.xml

@@ -435,6 +435,35 @@
 					</webResources>
 				</configuration>
 			</plugin>
+
+			<plugin>
+    <groupId>org.apache.maven.plugins</groupId>
+    <artifactId>maven-checkstyle-plugin</artifactId>
+    <version>3.3.1</version>
+    <dependencies>
+        <dependency>
+            <groupId>com.puppycrawl.tools</groupId>
+            <artifactId>checkstyle</artifactId>
+            <version>10.12.7</version>
+        </dependency>
+    </dependencies>
+    <configuration>
+        <configLocation>checkstyle.xml</configLocation>
+        <encoding>UTF-8</encoding>
+        <consoleOutput>true</consoleOutput>
+        <failsOnError>true</failsOnError>
+        <linkXRef>false</linkXRef>
+    </configuration>
+    <executions>
+        <execution>
+            <id>validate</id>
+            <phase>validate</phase>
+            <goals>
+                <goal>check</goal>
+            </goals>
+        </execution>
+    </executions>
+</plugin>
 		</plugins>
 	</build>