not using deprecated FileTypeFactory

resources/META-INF/plugin.xml

@@ -33,7 +33,8 @@
     </change-notes>
 
     <extensions defaultExtensionNs="com.intellij">
-        <fileTypeFactory implementation="org.jetbrains.plugins.hocon.lang.HoconFileTypeFactory"/>
+        <fileType implementationClass="org.jetbrains.plugins.hocon.lang.HoconFileType"
+                  name="HOCON" language="HOCON" extensions="conf"/>
         <lang.syntaxHighlighterFactory language="HOCON"
                                        implementationClass="org.jetbrains.plugins.hocon.highlight.HoconSyntaxHighlighterFactory"/>
         <lang.parserDefinition language="HOCON"

src/org/jetbrains/plugins/hocon/indexing/indices.scala

@@ -118,7 +118,7 @@ abstract class HKeyIndex[K](companion: HKeyIndexCompanion[K])
   def getValueExternalizer: DataExternalizer[HKeyOccurrences] = HKeyOccurrences.Externalizer
 
   def acceptInput(file: VirtualFile): Boolean =
-    file.getFileType == HoconFileType
+    HoconFileType.isHocon(file.getFileType)
 
   def map(inputData: FileContent): JMap[K, HKeyOccurrences] = inputData.getPsiFile match {
     case hf: HoconPsiFile =>

src/org/jetbrains/plugins/hocon/lang/HoconFileType.scala

@@ -1,14 +1,20 @@
 package org.jetbrains.plugins.hocon
 package lang
 
-import com.intellij.openapi.fileTypes.LanguageFileType
+import com.intellij.openapi.fileTypes.{FileType, LanguageFileType}
 import javax.swing.Icon
 
-object HoconFileType extends LanguageFileType(HoconLanguage) {
-  val DefaultExtension = "conf"
-
+final class HoconFileType extends LanguageFileType(HoconLanguage) {
   def getIcon: Icon = HoconIcon
-  def getDefaultExtension: String = DefaultExtension
+  def getDefaultExtension: String = HoconFileType.DefaultExtension
   def getDescription = "HOCON"
   def getName = "HOCON"
 }
+object HoconFileType {
+  val DefaultExtension = "conf"
+
+  def isHocon(fileType: FileType): Boolean = fileType match {
+    case _: HoconFileType => true
+    case _ => false
+  }
+}

src/org/jetbrains/plugins/hocon/navigation/HoconFindUsagesHandler.scala

@@ -112,7 +112,7 @@ class HoconUseScopeAdjuster extends UseScopeEnlarger with ScopeOptimizer {
       new EverythingGlobalScope(project) {
         // HOCON files in library sources are just duplicates of the same HOCON files in regular library jars
         override def contains(file: VirtualFile): Boolean =
-          !(file.getFileType == HoconFileType && pfi.isInLibrarySource(file))
+          !(HoconFileType.isHocon(file.getFileType) && pfi.isInLibrarySource(file))
       }
     case _ =>
       super.getRestrictedUseScope(element)

src/org/jetbrains/plugins/hocon/psi/HoconPsiElement.scala

@@ -42,7 +42,7 @@ class HoconPsiFile(provider: FileViewProvider)
     visitor.visitFile(this)
 
   def getFileType: FileType =
-    HoconFileType
+    new HoconFileType
 
   def toplevelChild: HoconPsiElement =
     findChildByClass(classOf[HoconPsiElement])

src/org/jetbrains/plugins/hocon/psi/HoconPsiElementFactory.scala

@@ -11,7 +11,7 @@ object HoconPsiElementFactory {
 
   private def createElement[T <: HoconPsiElement : ClassTag](manager: PsiManager, text: String, offset: Int): Option[T] = {
     val element = PsiFileFactory.getInstance(manager.getProject)
-      .createFileFromText(Dummy + HoconFileType.DefaultExtension, HoconFileType, text).findElementAt(offset)
+      .createFileFromText(Dummy + HoconFileType.DefaultExtension, new HoconFileType, text).findElementAt(offset)
     Iterator.iterate(element)(_.getParent).takeWhile(_ != null).collectFirst({ case t: T => t })
   }