Remove uses of ReflectiveCalls from Code

- remove need for reflection by using traits instead of structural typing since scala 3 has a different import scala.reflect.Selectables... from scala 2.13 which uses scala.language.reflectiveCalls. Neither import exist in the other version and are therefore incompatible, so the easiest approach was to get rid of structural typing in lieu of traits.
- add comments for 2.12 phaseout
- remove JDOMUtils

DAFFODIL-2975

Author: olabusayoT

daffodil-io/src/main/scala/org/apache/daffodil/io/processors/charset/BitsCharsetDefinition.scala

@@ -16,13 +16,18 @@
  */
 package org.apache.daffodil.io.processors.charset
 
+import org.apache.daffodil.lib.util.SimpleNamedLoadableService
+
 /**
  * These are the classes which must be dynamically loaded in order to add a charset implementation
  * to Daffodil. All charsets must implement this class and be added to the 
  * org.apache.daffodil.runtime1.processors.charset.BitsCharsetDefinition file in 
  * daffodil-io/src/main/resources/META-INF/services. name() must return a fully capitalized string
  */
-abstract class BitsCharsetDefinition(charset: BitsCharset, alias: Option[String] = None) {
+abstract class BitsCharsetDefinition(
+  charset: BitsCharset,
+  alias: Option[String] = None
+) extends SimpleNamedLoadableService {
   final def name(): String = alias.getOrElse(charset.name).toUpperCase()
 
   final def charset(): BitsCharset = charset

daffodil-lib/src/main/scala/org/apache/daffodil/lib/Implicits.scala

@@ -19,7 +19,6 @@ package org.apache.daffodil.lib
 
 import java.io.{ BufferedInputStream, ByteArrayInputStream }
 import scala.language.implicitConversions
-import scala.language.reflectiveCalls
 
 import org.apache.daffodil.lib.exceptions.Assert
 import org.apache.daffodil.lib.xml.NS
@@ -47,10 +46,10 @@ object Implicits {
 
   /**
    * Used for reading/writing to database, files, etc.
-   * Code From the book "Beginning Scala"
-   * http://www.amazon.com/Beginning-Scala-David-Pollak/dp/1430219890
+   * Code without reflection
+   * TODO: scala 2.12 Phaseout. Replace with scala.util.Using
    */
-  def using[A <: { def close(): Unit }, B](param: A)(f: A => B): B =
+  def using[A <: AutoCloseable, B](param: A)(f: A => B): B =
     try { f(param) }
     finally { param.close() }
 

daffodil-lib/src/main/scala/org/apache/daffodil/lib/api/Validator.scala

@@ -17,6 +17,8 @@
 
 package org.apache.daffodil.lib.api
 
+import org.apache.daffodil.lib.util.SimpleNamedLoadableService
+
 import com.typesafe.config.Config
 
 /**
@@ -35,7 +37,7 @@ trait Validator {
  *
  * The factory implementations are expected to be thread safe
  */
-trait ValidatorFactory {
+trait ValidatorFactory extends SimpleNamedLoadableService {
 
   /**
    * Unique name of this Validator service

daffodil-lib/src/main/scala/org/apache/daffodil/lib/util/Misc.scala

@@ -638,11 +638,11 @@ object Misc {
     }
   }
 
-  import scala.language.reflectiveCalls // scala 2.10 creates warning unless we have this.
   /**
    * Convenient I/O tools
+   * TODO: scala 2.12 Phaseout. Replace with scala.util.Using
    */
-  def using[A <: { def close(): Unit }, B](param: A)(f: A => B): B =
+  def using[A <: AutoCloseable, B](param: A)(f: A => B): B =
     try { f(param) }
     finally { param.close() }
 

daffodil-lib/src/main/scala/org/apache/daffodil/lib/util/SimpleNamedServiceLoader.scala

@@ -19,7 +19,8 @@ package org.apache.daffodil.lib.util
 import java.util.ServiceConfigurationError
 import java.util.ServiceLoader
 import scala.collection.mutable.ArrayBuffer
-import scala.language.reflectiveCalls
+
+trait SimpleNamedLoadableService { def name(): String }
 
 /**
  * Contains methods for dynamic loading of classes from the class path.
@@ -39,7 +40,7 @@ object SimpleNamedServiceLoader {
    *           It must have a name member returning a string. It must have a default (no-arg) constructor.
    * @return A map from the name (string) to the corresponding instance of the class.
    */
-  def loadClass[T <: { def name(): String }](clazz: Class[T]): Map[String, T] = {
+  def loadClass[T <: SimpleNamedLoadableService](clazz: Class[T]): Map[String, T] = {
     val thingName = Misc.getNameGivenAClassObject(clazz)
     val iter = ServiceLoader.load(clazz).iterator()
     val instanceBuf = new ArrayBuffer[T]

daffodil-lib/src/main/scala/org/apache/daffodil/lib/xml/JDOMUtils.scala

@@ -19,7 +19,6 @@ package org.apache.daffodil.lib.xml
 
 import java.net.URI
 import java.net.URISyntaxException
-import scala.language.reflectiveCalls
 import scala.util.Try
 
 import org.apache.daffodil.lib.api.UnqualifiedPathStepPolicy
@@ -486,23 +485,6 @@ final case class StepQName(prefix: Option[String], local: String, namespace: NS)
       case _ => Assert.usageError("other must be a NamedQName")
     }
   }
-
-  /**
-   * Finds the matches in a list of things that have QNames.
-   * Used for finding if a named path step has corresponding element declaration.
-   *
-   * Handles local or global matches
-   *
-   */
-  def findMatches[T <: { def namedQName: NamedQName }](candidates: Seq[T]): Seq[T] = {
-    val matched = candidates.filter { x =>
-      val other = x.namedQName
-      val res = matches(other)
-      res
-    }
-    matched
-  }
-
 }
 
 protected trait RefQNameFactoryBase[T] {

daffodil-lib/src/main/scala/org/apache/daffodil/lib/xml/QNameBase.scala

@@ -20,7 +20,6 @@ package org.apache.daffodil.lib.util
 import java.io.File
 import javax.xml.XMLConstants
 import javax.xml.parsers.SAXParser
-import scala.language.reflectiveCalls
 import scala.xml.Attribute
 import scala.xml.Elem
 import scala.xml.MetaData
@@ -31,8 +30,8 @@ import scala.xml.SAXParseException
 import scala.xml.Text
 import scala.xml.parsing.NoBindingFactoryAdapter
 
+import org.apache.daffodil.lib.Implicits.using
 import org.apache.daffodil.lib.exceptions.Assert
-import org.apache.daffodil.lib.util.Implicits.using
 import org.apache.daffodil.lib.util.collections.Stack
 import org.apache.daffodil.lib.xml.DaffodilSAXParserFactory
 import org.apache.daffodil.lib.xml.NS
@@ -53,19 +52,6 @@ import org.xml.sax.InputSource
 import org.xml.sax.XMLReader
 import org.xml.sax.helpers.XMLFilterImpl
 
-object Implicits {
-
-  /**
-   * Used for reading/writing to database, files, etc.
-   * Code From the book "Beginning Scala"
-   * http://www.amazon.com/Beginning-Scala-David-Pollak/dp/1430219890
-   */
-  def using[A <: { def close(): Unit }, B](param: A)(f: A => B): B =
-    try { f(param) }
-    finally { param.close() }
-
-}
-
 /**
  * The goal here is to integrate XML Catalog with XSD Validation, so that both
  * the DFDL Schema references to other DFDL Schema namespaces would be resolved via

daffodil-lib/src/test/scala/org/apache/daffodil/lib/util/TestXMLCatalogAndValidate.scala

@@ -24,7 +24,6 @@ import java.nio.file.StandardOpenOption
 import scala.xml._
 
 import org.apache.daffodil.lib.util.Misc
-import org.apache.daffodil.lib.xml.JDOMUtils
 import org.apache.daffodil.lib.xml.NS
 import org.apache.daffodil.lib.xml.XMLUtils
 
@@ -159,13 +158,6 @@ class TestXMLUtils {
     assertFalse(isSame)
   }
 
-  @Test def testIsNil(): Unit = {
-    val d1 = JDOMUtils.elem2Element(<a xmlns:xsi={XMLUtils.XSI_NAMESPACE} xsi:nil="true"/>)
-    val d2 = JDOMUtils.elem2Element(<a xmlns:xsi={XMLUtils.XSI_NAMESPACE}>foo</a>)
-    assertTrue(JDOMUtils.isNil(d1))
-    assertFalse(JDOMUtils.isNil(d2))
-  }
-
   @Test def testWalkUnicodeString1(): Unit = {
     val s = "abc"
     val Seq((ab, 'a', 'b'), ('a', 'b', 'c'), ('b', 'c', ca)) =

daffodil-lib/src/test/scala/org/apache/daffodil/lib/xml/test/unit/TestXMLUtils.scala

@@ -459,12 +459,31 @@ class DPathElementCompileInfo(
     matches(0)
   }
 
+  /**
+   * Finds the matches in a list of DPathElementCompileInfo.
+   * Used for finding if a named path step has corresponding element declaration.
+   *
+   * Handles local or global matches
+   *
+   */
+  def findMatches(
+    step: StepQName,
+    candidates: Seq[DPathElementCompileInfo]
+  ): Seq[DPathElementCompileInfo] = {
+    val matched = candidates.filter { x =>
+      val other = x.namedQName
+      val res = step.matches(other)
+      res
+    }
+    matched
+  }
+
   private def findNamedMatches(
     step: StepQName,
     possibles: Seq[DPathElementCompileInfo],
     expr: ImplementsThrowsOrSavesSDE
   ): Seq[DPathElementCompileInfo] = {
-    val matchesERD: Seq[DPathElementCompileInfo] = step.findMatches(possibles)
+    val matchesERD: Seq[DPathElementCompileInfo] = findMatches(step, possibles)
 
     val retryMatchesERD =
       if (
@@ -476,7 +495,7 @@ class DPathElementCompileInfo(
         // default namespace was assumed but didn't match, the unqualified path
         // step policy allows us to try to match NoNamespace elements.
         val noNamespaceStep = step.copy(namespace = NoNamespace)
-        noNamespaceStep.findMatches(possibles)
+        findMatches(noNamespaceStep, possibles)
       } else {
         matchesERD
       }
@@ -493,7 +512,7 @@ class DPathElementCompileInfo(
     step: StepQName,
     possibles: Seq[DPathElementCompileInfo]
   ): Seq[DPathElementCompileInfo] = {
-    val matchesERD = step.findMatches(possibles)
+    val matchesERD = findMatches(step, possibles)
     val retryMatchesERD =
       if (
         matchesERD.isEmpty &&
@@ -504,7 +523,7 @@ class DPathElementCompileInfo(
         // default namespace was assumed but didn't match, the unqualified path
         // step policy allows us to try to match NoNamespace elements.
         val noNamespaceStep = step.copy(namespace = NoNamespace)
-        noNamespaceStep.findMatches(possibles)
+        findMatches(noNamespaceStep, possibles)
       } else {
         matchesERD
       }

daffodil-runtime1/src/main/scala/org/apache/daffodil/runtime1/dsom/CompiledExpression1.scala

@@ -16,6 +16,7 @@
  */
 package org.apache.daffodil.runtime1.layers.api;
 
+import org.apache.daffodil.lib.util.SimpleNamedLoadableService;
 import org.apache.daffodil.runtime1.layers.LayerRuntime;
 import org.apache.daffodil.runtime1.layers.LayerUtils;
 
@@ -257,7 +258,7 @@
  * <p>
  * Unhandled exceptions thrown by the layer code are treated as fatal errors.
  */
-public abstract class Layer {
+public abstract class Layer implements SimpleNamedLoadableService {
 
   private final String localName;
   private final String targetNamespace;