Proper loading of 3rd party rulesets and reporters. (pinterest#577)

Unblocks using them on on java 9+.

Signed-off-by: Yahor Berdnikau <egorr.berd@gmail.com>

ktlint/src/main/kotlin/com/pinterest/ktlint/Main.kt

@@ -23,7 +23,6 @@ import com.pinterest.ktlint.internal.printHelpOrVersionUsage
 import java.io.File
 import java.io.IOException
 import java.io.PrintStream
-import java.net.URL
 import java.net.URLClassLoader
 import java.net.URLDecoder
 import java.nio.file.Paths
@@ -223,9 +222,6 @@ class KtlintCommandLine {
  }
  val start = System.currentTimeMillis()
 
- // load 3rd party ruleset(s) (if any)
- if (rulesets.isNotEmpty()) loadJARs(rulesets)
-
  // Detect custom rulesets that have not been moved to the new package
  if (ServiceLoader.load(com.github.shyiko.ktlint.core.RuleSetProvider::class.java).any()) {
  System.err.println("[ERROR] Cannot load custom ruleset!")
@@ -234,17 +230,9 @@ class KtlintCommandLine {
  exitProcess(1)
  }
 
- // standard should go first
- val ruleSetProviders =
- ServiceLoader.load(RuleSetProvider::class.java)
- .map { it.get().id to it }
- .filter { (id) -> experimental || id != "experimental" }
- .sortedBy { if (it.first == "standard") "\u0000${it.first}" else it.first }
- if (debug) {
- ruleSetProviders.forEach { System.err.println("[DEBUG] Discovered ruleset \"${it.first}\"") }
- }
+ val ruleSetProviders = loadRulesets(rulesets)
  val tripped = AtomicBoolean()
- val reporter = loadReporter() { tripped.get() }
+ val reporter = loadReporter { tripped.get() }
  data class LintErrorWithCorrectionInfo(val err: LintError, val corrected: Boolean)
  val userData = listOfNotNull(
  "android" to android.toString(),
@@ -262,7 +250,7 @@ class KtlintCommandLine {
  formatFile(
  fileName,
  fileContent,
- ruleSetProviders.map { it.second.get() },
+ ruleSetProviders.map { it.value.get() },
  userData,
  editorConfigPath,
  debug
@@ -289,7 +277,7 @@ class KtlintCommandLine {
  lintFile(
  fileName,
  fileContent,
- ruleSetProviders.map { it.second.get() },
+ ruleSetProviders.map { it.value.get() },
  userData,
  editorConfigPath,
  debug
@@ -363,20 +351,7 @@ class KtlintCommandLine {
  )
  }
  .distinct()
- val reporterLoader = ServiceLoader.load(ReporterProvider::class.java)
- val reporterProviderById = reporterLoader.associateBy { it.id }
- val missingReporters = tpls
- .filter { !reporterProviderById.containsKey(it.id) }
- .mapNotNull { it.artifact }
- .distinct()
- if (missingReporters.isNotEmpty()) {
- loadJARs(missingReporters)
- reporterLoader.reload()
- reporterLoader.associateBy { it.id }
- }
- if (debug) {
- reporterProviderById.forEach { (id) -> System.err.println("[DEBUG] Discovered reporter \"$id\"") }
- }
+ val reporterProviderById = loadReporters(tpls.mapNotNull { it.artifact })
  fun ReporterTemplate.toReporter(): Reporter {
  val reporterProvider = reporterProviderById[id]
  if (reporterProvider == null) {
@@ -478,22 +453,6 @@ class KtlintCommandLine {
 
  private fun <T> List<T>.head(limit: Int) = if (limit == size) this else this.subList(0, limit)
 
- // fixme: isn't going to work on JDK 9
- private fun loadJARs(artifacts: List<String>) {
- val jarUrls = artifacts
- .map {
- val artifactFile = File(expandTilde(it))
- if (!artifactFile.exists()) {
- System.err.println("Error: $it does not exist")
- exitProcess(1)
- }
- artifactFile.toURI().toURL()
- }
-
- val classLoader = ClassLoader.getSystemClassLoader() as URLClassLoader
- classLoader.addURLs(jarUrls)
- }
-
  private fun parseQuery(query: String) =
  query.split("&")
  .fold(LinkedHashMap<String, String>()) { map, s ->
@@ -508,12 +467,6 @@ class KtlintCommandLine {
  map
  }
 
- private fun URLClassLoader.addURLs(url: Iterable<URL>) {
- val method = URLClassLoader::class.java.getDeclaredMethod("addURL", URL::class.java)
- method.isAccessible = true
- url.forEach { method.invoke(this, it) }
- }
-
  private fun File.mkdirsOrFail() {
  if (!mkdirs() && !isDirectory) {
  throw IOException("Unable to create \"${this}\" directory")
@@ -578,4 +531,47 @@ class KtlintCommandLine {
  producer.join()
  }
  }
+
+ private fun loadRulesets(externalRulesetsJarPaths: List<String>) = ServiceLoader
+ .load(
+ RuleSetProvider::class.java,
+ URLClassLoader(externalRulesetsJarPaths.toFilesURIList().toTypedArray())
+ )
+ .associateBy {
+ val key = it.get().id
+ // standard should go first
+ if (key == "standard") "\u0000$key" else key
+ }
+ .filterKeys { experimental || it != "experimental" }
+ .toSortedMap()
+ .also {
+ if (debug) {
+ it.forEach { entry ->
+ println("[DEBUG] Discovered ruleset with \"${entry.key}\" id.")
+ }
+ }
+ }
+
+ private fun loadReporters(externalReportersJarPaths: List<String>) = ServiceLoader
+ .load(
+ ReporterProvider::class.java,
+ URLClassLoader(externalReportersJarPaths.toFilesURIList().toTypedArray())
+ )
+ .associateBy { it.id }
+ .also {
+ if (debug) {
+ it.forEach { entry ->
+ println("[DEBUG] Discovered reporter with \"${entry.key}\" id.")
+ }
+ }
+ }
+
+ private fun List<String>.toFilesURIList() = map {
+ val jarFile = File(expandTilde(it))
+ if (!jarFile.exists()) {
+ println("Error: $it does not exist")
+ exitProcess(1)
+ }
+ jarFile.toURI().toURL()
+ }
 }