Add gradle example

Author: adangel

.github/workflows/build.yml

@@ -98,3 +98,25 @@ jobs:
         run: |
           cd maven/simple-project
           .ci/build.sh
+
+  gradle_simple_project:
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-java@v4
+        with:
+          distribution: 'temurin'
+          java-version: '17'
+      - uses: actions/cache@v4
+        with:
+          path: |
+            ~/.gradle/caches
+            ~/.gradle/wrapper
+          key: ${{ runner.os }}-gradle-${{ hashFiles('**/*.gradle*', '**/gradle-wrapper.properties') }}
+          restore-keys: |
+            ${{ runner.os }}-gradle-
+      - name: Run .ci/build.sh
+        run: |
+          cd gradle/simple-project
+          .ci/build.sh

README.md

@@ -3,8 +3,9 @@
 This repository contains separate folders for specific use cases:
 
 *   Creating Custom Rules
-    *   For Java: <custom-rules/maven-java/>
-    *   For PLSQL: <custom-rules/maven-plsql/>
-    *   For Java, but without maven: <custom-rules/plain-java/>
+    *   For Java: [custom-rules/maven-java/](custom-rules/maven-java/)
+    *   For PLSQL: [custom-rules/maven-plsql/](custom-rules/maven-plsql/)
+    *   For Java, but without maven: [custom-rules/plain-java/](custom-rules/plain-java/)
 *   Using PMD
-    *   With Maven: <maven/simple-project/>
+    *   With Maven: [maven/simple-project/](maven/simple-project/)
+    *   With Gradle: [gradle/simple-project/](gradle/simple-project/)

gradle/simple-project/.ci/build.sh

@@ -0,0 +1,12 @@
+#!/bin/bash
+
+# exit immediately if a command fails
+set -e
+
+./gradlew check 2>&1 | tee build.log
+
+echo
+echo "Verifying build.log..."
+grep "2 PMD rule violations were found." build.log || (echo -e "\n\n\x1b[31mMissing expected rule violation\e[0m"; exit 1)
+
+echo -e "\n\n\x1b[32mTest successful\e[0m"

gradle/simple-project/.gitattributes

@@ -0,0 +1,9 @@
+#
+# https://help.github.com/articles/dealing-with-line-endings/
+#
+# Linux start script should use lf
+/gradlew        text eol=lf
+
+# These are Windows script files and should use crlf
+*.bat           text eol=crlf
+

gradle/simple-project/.gitignore

@@ -0,0 +1,5 @@
+# Ignore Gradle project-specific cache directory
+.gradle
+
+# Ignore Gradle build output directory
+build

gradle/simple-project/README.md

@@ -0,0 +1,17 @@
+# simple-project
+
+Demonstrates the usage of PMD with Gradle.
+
+Run with
+
+    ./gradlew check
+
+This should find the following violations in App.java:
+
+    .../pmd-examples/gradle/simple-project/app/src/main/java/org/example/App.java:8:   UnusedPrivateField:     Avoid unused private fields such as 'unusedField'.
+    .../pmd-examples/gradle/simple-project/app/src/main/java/org/example/App.java:16:  SystemPrintln:  Usage of System.out/err
+
+## References
+
+*   <https://docs.pmd-code.org/latest/pmd_userdocs_tools_gradle.html>
+*   <https://docs.gradle.org/current/userguide/pmd_plugin.html>

gradle/simple-project/app/build.gradle

@@ -0,0 +1,55 @@
+/*
+ * This file was generated by the Gradle 'init' task.
+ *
+ * This generated file contains a sample Java application project to get you started.
+ * For more details on building Java & JVM projects, please refer to https://docs.gradle.org/8.6/userguide/building_java_projects.html in the Gradle documentation.
+ */
+
+plugins {
+    // Apply the application plugin to add support for building a CLI application in Java.
+    id 'application'
+    id 'pmd'
+}
+
+repositories {
+    // Use Maven Central for resolving dependencies.
+    mavenCentral()
+    maven {
+        url "https://oss.sonatype.org/content/repositories/snapshots/"
+    }
+}
+
+dependencies {
+    // Use JUnit Jupiter for testing.
+    testImplementation libs.junit.jupiter
+
+    testRuntimeOnly 'org.junit.platform:junit-platform-launcher'
+
+    // This dependency is used by the application.
+    implementation libs.guava
+}
+
+// Apply a specific Java toolchain to ease working on different environments.
+java {
+    toolchain {
+        languageVersion = JavaLanguageVersion.of(17)
+    }
+}
+
+application {
+    // Define the main class for the application.
+    mainClass = 'org.example.App'
+}
+
+tasks.named('test') {
+    // Use JUnit Platform for unit tests.
+    useJUnitPlatform()
+}
+
+pmd {
+    toolVersion = "7.0.0-SNAPSHOT"
+    consoleOutput = true
+
+    //ruleSets = ["category/java/errorprone.xml"] // default
+    ruleSets = ["category/java/errorprone.xml", "category/java/bestpractices.xml"]
+}

gradle/simple-project/app/src/main/java/org/example/App.java

@@ -0,0 +1,18 @@
+/*
+ * This Java source file was generated by the Gradle 'init' task.
+ */
+package org.example;
+
+public class App {
+    // UnusedPrivateField
+    private String unusedField = "unused";
+
+    public String getGreeting() {
+        return "Hello World!";
+    }
+
+    public static void main(String[] args) {
+        // SystemPrintln
+        System.out.println(new App().getGreeting());
+    }
+}

gradle/simple-project/app/src/test/java/org/example/AppTest.java

@@ -0,0 +1,14 @@
+/*
+ * This Java source file was generated by the Gradle 'init' task.
+ */
+package org.example;
+
+import org.junit.jupiter.api.Test;
+import static org.junit.jupiter.api.Assertions.*;
+
+class AppTest {
+    @Test void appHasAGreeting() {
+        App classUnderTest = new App();
+        assertNotNull(classUnderTest.getGreeting(), "app should have a greeting");
+    }
+}

gradle/simple-project/gradle/libs.versions.toml

@@ -0,0 +1,10 @@
+# This file was generated by the Gradle 'init' task.
+# https://docs.gradle.org/current/userguide/platforms.html#sub::toml-dependencies-format
+
+[versions]
+guava = "32.1.3-jre"
+junit-jupiter = "5.10.0"
+
+[libraries]
+guava = { module = "com.google.guava:guava", version.ref = "guava" }
+junit-jupiter = { module = "org.junit.jupiter:junit-jupiter", version.ref = "junit-jupiter" }