build(rollbar-java): migrate build.gradle to Kotlin and fix failing CI

Author: buongarzoni

rollbar-java/build.gradle

@@ -0,0 +1,96 @@
+import java.io.File
+
+plugins {
+    id("com.netflix.nebula.integtest") version "10.0.1"
+}
+
+val integTestArtifacts by configurations.creating
+val integTestRuntime by configurations.creating {
+    extendsFrom(configurations["integTestImplementation"])
+    isCanBeConsumed = true
+    isCanBeResolved = true
+}
+
+dependencies {
+    api(project(":rollbar-api"))
+    api("org.slf4j:slf4j-api:1.7.25")
+
+    compileOnly("com.google.code.findbugs:jsr305:3.0.2")
+
+    testImplementation("com.google.code.gson:gson:2.8.6")
+
+    "integTestImplementation"("com.github.tomakehurst:wiremock:2.27.0")
+    "integTestImplementation"("com.google.code.gson:gson:2.8.2")
+}
+
+val versionName = project.version.toString().ifEmpty { "unspecified" }
+
+/**
+ * This task will create a version property that is statically referenced when populating the
+ * `notifier` section of the payload. It helps when users shade and / or relocate the
+ * `rollbar-java` classes, since in those cases we no longer have access to our jar manifest.
+ * The task creates a Java class instead of a text resource, since dynamically loaded resources
+ * are not as reliable under relocation as a strongly typed bytecode reference to a compiled class.
+ */
+val createVersionClass by tasks.registering {
+    val outputDir = layout.buildDirectory.dir("src/generated/main")
+    outputs.dir(outputDir)
+
+    doLast {
+        val pkg = listOf("com", "rollbar", "notifier", "provider", "notifier")
+        val pkgName = pkg.joinToString(".")
+        val pkgPath = outputDir.get().asFile.resolve(pkg.joinToString(File.separator))
+        val escapedVersion = versionName.replace("\\", "\\\\").replace("\"", "\\\"")
+
+        val classText = """
+            package $pkgName;
+
+            class VersionHelperResources {
+              static String getVersion() {
+                return "$escapedVersion";
+              }
+            }
+        """.trimIndent()
+
+        pkgPath.mkdirs()
+        pkgPath.resolve("VersionHelperResources.java").writeText(classText)
+    }
+}
+
+sourceSets {
+    named("main") {
+        java.srcDir(createVersionClass.map { it.outputs.files.singleFile })
+    }
+}
+
+tasks.named("compileJava") {
+    dependsOn(createVersionClass)
+}
+
+tasks.named("checkstyleMain") {
+    dependsOn(createVersionClass)
+}
+
+//Ensure sourcesJar runs after version class is created
+tasks.withType<Jar>().configureEach {
+    if (name == "sourcesJar") {
+        dependsOn(createVersionClass)
+    }
+}
+
+tasks.test {
+    // This helps us test the VersionHelper class since there's no jar manifest available when
+    // running tests.
+    systemProperty("ROLLBAR_IMPLEMENTATION_VERSION", versionName)
+}
+
+// The 'java-test-fixtures' plugin is not getting along with 'nebula.integtest', so we'll use this instead
+val integTestJar by tasks.registering(Jar::class) {
+    archiveClassifier.set("integtest")
+    from(sourceSets["integTest"].output)
+    dependsOn(tasks.named("integTestClasses"))
+}
+
+artifacts {
+    add("integTestArtifacts", integTestJar)
+}