Refactor ingester code.

Use RDFDataMgr interface instead of model writer.
Replace constants with variables.

src/main/kotlin/Ingester.kt

@@ -21,6 +21,8 @@ import java.io.File
 import java.io.StringWriter
 import java.net.URI
 import org.apache.jena.rdf.model.Model
+import org.apache.jena.riot.Lang
+import org.apache.jena.riot.RDFDataMgr
 import org.apache.logging.log4j.LogManager
 import org.fcrepo.client.FcrepoOperationFailedException
 import org.memobase.fedora.FedoraClient
@@ -39,14 +41,11 @@ class Ingester(
 
     @Throws(FcrepoOperationFailedException::class)
     fun ingest(id: String, content: String) {
-        log.info("Ingest record $id.")
-        log.info("Content: $content")
+        log.info("Begin ingest of message with id $id.")
         val rdfHandler = RdfHandler(content, externalBaseUrl)
-
         val recordOutput = StringWriter()
         val recordPair = rdfHandler.getRecord()
-        recordPair.second.write(recordOutput, "NTRIPLES")
-
+        RDFDataMgr.write(recordOutput, recordPair.second, Lang.NTRIPLES)
         val data = recordOutput.toString()
 
         fedoraClient.startTransaction().use { transaction ->
@@ -64,7 +63,7 @@ class Ingester(
             transaction.createOrUpdateRdfResource(URI(recordPair.first), data, RdfContentTypes.NTRIPLES)
             ingestInstantiations(rdfHandler.getInstantiations(), transaction)
             val sftpLocators = rdfHandler.getSftpLocators()
-            if (sftpLocators.size > 0) {
+            if (sftpLocators.isNotEmpty()) {
                 ingestBinaries(sftpLocators, rdfHandler, transaction)
             }
             transaction.commit()
@@ -75,7 +74,7 @@ class Ingester(
     private fun ingestInstantiations(instantiations: List<Pair<String, Model>>, transaction: FedoraTransactionClient) {
         instantiations.forEach { instantiationPair ->
             val instantiationOutput = StringWriter()
-            instantiationPair.second.write(instantiationOutput, "NTRIPLES")
+            RDFDataMgr.write(instantiationOutput, instantiationPair.second, Lang.NTRIPLES)
             val instantiationData = instantiationOutput.toString()
             log.info("Ingesting instantiation ${instantiationPair.first}.")
             transaction.createOrUpdateRdfResource(URI(instantiationPair.first), instantiationData, RdfContentTypes.NTRIPLES)
@@ -91,7 +90,7 @@ class Ingester(
                 it.second.let { path ->
                     if (path != null) {
                         sftpClient.open(File(path)).use { stream ->
-                            val binaryUri = "${it.first}/binary"
+                            val binaryUri = "${it.first}/${Service.BINARY_FILE_URI_PATH}"
                             val mimeType = rdfHandler.getMimeType().first { mT ->
                                 mT.first == digitalInstantiationUrl
                             }.second