Update scaladocs mentioning deprecated API

Ensure nothing mentions the deprecated API removed in previous commits
for DAFFODIL-2743.  Also fix some IDEA nits and improve DataProcessor
constructor.

SchemaSet.scala: Simplify scaladoc to stop mentioning deprecated API.
Fix some IDEA nits in the same code block with IDEA quick fixes.

SchemaSetRuntime1Mixin.scala: Make onPath call first DataProcessor
constructor instead of now-deleted second constructor.

DataProcessor.scala: Make SerializedDataProcessor extend first
DataProcessor constructor instead of now-deleted second
constructor. Change first DataProcessor constructor from private to
public, reorder its last 4 parameters, and make its last 2 parameters
optional.  Delete second DataProcessor constructor and remove its
scaladoc which had been saying it was using deprecated
compilerExternalVars.  Make copy call first constructor with reordered
parameters.  Remove another scaladoc which had been mentioning tunables
not even passed to method anymore.

DAFFODIL-2743

daffodil-core/src/main/scala/org/apache/daffodil/dsom/SchemaSet.scala

@@ -342,13 +342,9 @@ final class SchemaSet private (
   }
 
   /**
-   * The root element can be specified by a deprecated API call on the compiler
-   * object or the ProcessorFactory class, but the call on the ProcessorFactory class
-   * just overrides anything coming from the compiler object.
+   * You can define the root by passing the root specification to the Compiler.compileX method.
    *
-   * The right way is to pass the root specification to the Compiler.compileX method.
-   *
-   * Or, you can leave it unspecified, and this method will determine from the
+   * Or, you can leave the root unspecified, and this method will determine it from the
    * first element declaration of the first schema file.
    */
   lazy val root: Root = {
@@ -360,12 +356,12 @@ final class SchemaSet private (
           // if the root element and rootNamespace aren't provided at all, then
           // the first element of the first schema document is the root
           val sDocs = this.allSchemaDocuments
-          assuming(sDocs.length > 0)
-          val firstSchemaDocument = sDocs(0)
+          assuming(sDocs.nonEmpty)
+          val firstSchemaDocument = sDocs.head
           val gdecl = firstSchemaDocument.globalElementDecls
           val firstElement = {
-            schemaDefinitionUnless(gdecl.length >= 1, "No global elements in: " + firstSchemaDocument.uriString)
-            gdecl(0)
+            schemaDefinitionUnless(gdecl.nonEmpty, "No global elements in: " + firstSchemaDocument.uriString)
+            gdecl.head
           }
           firstElement
         }

daffodil-core/src/main/scala/org/apache/daffodil/runtime1/SchemaSetRuntime1Mixin.scala

@@ -30,6 +30,8 @@ import org.apache.daffodil.processors.parsers.NotParsableParser
 import org.apache.daffodil.processors.unparsers.NotUnparsableUnparser
 import org.apache.daffodil.util.Logger
 
+import scala.collection.immutable.Queue
+
 trait SchemaSetRuntime1Mixin {
   self: SchemaSet =>
 
@@ -75,7 +77,6 @@ trait SchemaSetRuntime1Mixin {
     root.schemaDefinitionUnless(
       !rootERD.dpathElementCompileInfo.isOutputValueCalc,
       "The root element cannot have the dfdl:outputValueCalc property.")
-    val validationMode = ValidationMode.Off
     val p = if (!root.isError) parser else null
     val u = if (!root.isError) unparser else null
     val ssrd = new SchemaSetRuntimeData(
@@ -87,7 +88,7 @@ trait SchemaSetRuntime1Mixin {
       typeCalcMap)
     if (root.numComponents > root.numUniqueComponents)
       Logger.log.debug(s"Compiler: component counts: unique ${root.numUniqueComponents}, actual ${root.numComponents}.")
-    val dataProc = new DataProcessor(ssrd, tunable)
+    val dataProc = new DataProcessor(ssrd, tunable, variableMap.copy(), Queue.empty, ValidationMode.Off)
     if (dataProc.isError) {
     } else {
       Logger.log.debug(s"Parser = ${ssrd.parser.toString}.")

daffodil-runtime1/src/main/scala/org/apache/daffodil/processors/DataProcessor.scala

@@ -104,7 +104,9 @@ object DataProcessor {
     tunable: DaffodilTunables,
     externalVars: Queue[Binding], // must be explicitly set to empty by save method
     validationModeArg: ValidationMode.Type) // must be explicitly set from Full to Limited by save method.
-    extends DataProcessor(data, tunable, externalVars, validationModeArg) {
+    extends DataProcessor(data, tunable,
+      ExternalVariablesLoader.loadVariables(externalVars, data, data.originalVariables),
+      externalVars, validationModeArg) {
 
     override def withValidationMode(mode: ValidationMode.Type): DataProcessor = {
       if (mode == ValidationMode.Full) {
@@ -119,7 +121,7 @@ object DataProcessor {
  * The very last aspects of compilation, and the start of the
  * back-end runtime.
  */
-class DataProcessor private (
+class DataProcessor(
   val ssrd: SchemaSetRuntimeData,
   val tunables: DaffodilTunables, // Compiler-set tunables
   val variableMap: VariableMap,
@@ -129,10 +131,10 @@ class DataProcessor private (
   // The values these will have (since this is a base class) are the correct default values that we want
   // back when the object is re-initialized.
   //
-  protected val areDebugging : Boolean,
-  protected val optDebugger : Option[Debugger],
+  private val externalVars: Queue[Binding],
   val validationMode: ValidationMode.Type,
-  private val externalVars: Queue[Binding])
+  protected val areDebugging : Boolean = false,
+  protected val optDebugger : Option[Debugger] = None)
   extends DFDL.DataProcessor
   with Serializable
   with MultipleEventHandler {
@@ -154,37 +156,21 @@ class DataProcessor private (
    * That means when we save for reloading, we must explicitly clobber validationMode and externalVars to
    * initialized values.
    *
-   * @throws java.io.ObjectStreamException
+   * @throws java.io.ObjectStreamException Must be part of writeReplace's API
    * @return the serializable object
    */
   @throws(classOf[java.io.ObjectStreamException])
   private def writeReplace() : Object =
     new SerializableDataProcessor(ssrd, tunables, externalVars, validationMode)
 
-  /**
-   * The compilerExternalVars argument supports the deprecated feature to assign external var bindings
-   * on the compiler object.
-   *
-   * These are just incorporated into the initial variable map of the data processor.
-   */
-
-  def this(
-    ssrd: SchemaSetRuntimeData,
-    tunables:DaffodilTunables,
-    compilerExternalVars: Queue[Binding] = Queue.empty,
-    validationMode: ValidationMode.Type = ValidationMode.Off) =
-    this(ssrd, tunables, ExternalVariablesLoader.loadVariables(compilerExternalVars, ssrd, ssrd.originalVariables),
-      false, None, validationMode, compilerExternalVars)
-
-  def copy(
-    ssrd: SchemaSetRuntimeData = ssrd,
-    tunables: DaffodilTunables = tunables,
-    areDebugging : Boolean = areDebugging,
-    optDebugger : Option[Debugger] = optDebugger,
-    validationMode: ValidationMode.Type = validationMode,
-    variableMap : VariableMap = variableMap.copy,
-    externalVars: Queue[Binding] = externalVars) =
-    new DataProcessor(ssrd, tunables, variableMap, areDebugging, optDebugger, validationMode,  externalVars)
+  def copy(ssrd: SchemaSetRuntimeData = ssrd,
+           tunables: DaffodilTunables = tunables,
+           variableMap: VariableMap = variableMap.copy(),
+           externalVars: Queue[Binding] = externalVars,
+           validationMode: ValidationMode.Type = validationMode,
+           areDebugging: Boolean = areDebugging,
+           optDebugger: Option[Debugger] = optDebugger) =
+    new DataProcessor(ssrd, tunables, variableMap, externalVars, validationMode, areDebugging, optDebugger)
 
   // This thread local state is used by the PState when it needs buffers for
   // regex matching. This cannot be in PState because a PState does not last
@@ -271,13 +257,6 @@ class DataProcessor private (
     copy(externalVars = newBindings)
   }
 
-  /**
-   * Note that tunables is not used. So this method is equivalent to
-   * the other similar method that doesn't take that parameter.
-   *
-   * @param extVars File containing configuration with external variable bindings in it.
-   * @param tunable This is ignored.
-   */
   def withExternalVariables(extVars: Seq[Binding]): DataProcessor = {
     val newBindings = loadExternalVariables(extVars)
     copy(externalVars = newBindings)