#8 - Add basic exception handling to IO operations

Closes #8.

src/main/scala/org/rosi_project/model_sync/generator/Generator.scala

@@ -4,7 +4,7 @@ import net.liftweb.json._
 import org.eclipse.emf.ecore._
 import org.eclipse.emf.ecore.resource.Resource
 import org.rosi_project.model_sync.generator.conversion.SModelGenerator
-import org.rosi_project.model_sync.generator.io.SModelFSWriter
+import org.rosi_project.model_sync.generator.io.{ClassWritingException, ModelImagePreparationException, SModelFSWriter}
 import org.rosi_project.model_sync.generator.sync.{GetterSetterGeneratingVisitor, SyncEnhancingVisitor}
 import scopt.OptionParser
 import scroll.internal.ecore.ECoreImporter
@@ -13,6 +13,7 @@ import scala.reflect.io.{Directory, File}
 import java.{io => jio}
 
 import org.rosi_project.model_sync.generator.acr_model.SModel
+import org.rosi_project.model_sync.generator.env.{CompilationException, JarPackaginException}
 
 import scala.io.Source
 
@@ -53,6 +54,7 @@ object Generator extends App {
     ).text("Remove the generated .scala files and only keep the compiled .class files")
   }
 
+  try {
     parser.parse(args, GeneratorConfig()) match {
       case Some(config) =>
 
@@ -60,7 +62,13 @@ object Generator extends App {
         implicit val jsonFormats: Formats = DefaultFormats
         val modelCfg = parse(modelJson).extract[ModelConfig]
 
-      val ecoreModel = loadEcore(config.source)
+        var ecoreModel: EPackage = null
+        try {
+          ecoreModel = loadEcore(config.source)
+        }  catch {
+          case e: Exception => throw new EcoreLoadException(e)
+        }
+
         val sModel = new SModelGenerator convert ecoreModel
         prepareModel(sModel, modelCfg)
         // write the model and create the JAR
@@ -84,6 +92,19 @@ object Generator extends App {
         }
       case None =>
     }
+  }
+  catch {
+    case ele: EcoreLoadException =>
+      println(s"** ERROR ** could not load ecore model: $ele")
+    case mipe: ModelImagePreparationException =>
+      println(s"** ERROR ** could not prepare model images: $mipe")
+    case cwe: ClassWritingException =>
+      println(s"** ERROR ** could not write classes: $cwe")
+    case ce: CompilationException =>
+      println(s"** ERROR ** could not compile classes: $ce")
+    case jpe: JarPackaginException =>
+      println(s"** ERROR ** could not package JAR: $jpe")
+  }
 
   /** Fetches an ecore model from XML.
     *
@@ -113,3 +134,5 @@ object Generator extends App {
   }
 
 }
+
+class EcoreLoadException(cause: Exception) extends RuntimeException(cause)

src/main/scala/org/rosi_project/model_sync/generator/env/FilesCompiler.scala

@@ -17,6 +17,7 @@ class FilesCompiler(outDir: File) {
     */
   def run(filesToCompile: List[File]): Unit = {
     // see: https://stackoverflow.com/a/20323371/5161760
+    try {
       val out = new PrintWriter(System.out)
       val compilationSettings: Settings = new GenericRunnerSettings(out.println)
       // just re-use the whole classpath
@@ -27,6 +28,15 @@ class FilesCompiler(outDir: File) {
       val compiler = new Global(compilationSettings, reporter)
       val runner = new compiler.Run
       runner.compile(filesToCompile.map(_.toAbsolute.toString))
+    } catch {
+      case e: Exception => throw new CompilationException(e)
+    }
   }
 
 }
+
+/** Exception to indicate that the compilation process failed.
+  *
+  * @param cause the causing exception
+  */
+class CompilationException(cause: Exception) extends RuntimeException(cause)

src/main/scala/org/rosi_project/model_sync/generator/env/JarPackager.scala

@@ -21,6 +21,7 @@ class JarPackager(inputDir: File, outputDir: File, jarName: String = "model.jar"
     */
   def run(): Unit = {
     // see: https://stackoverflow.com/a/1281295/5161760
+    try {
       val mf = new Manifest
       mf.getMainAttributes.put(Attributes.Name.MANIFEST_VERSION, "1.0")
       val targetJar = new JarOutputStream(new FileOutputStream(outputDir + File.separator + jarName), mf)
@@ -64,6 +65,15 @@ class JarPackager(inputDir: File, outputDir: File, jarName: String = "model.jar"
       }
 
       targetJar.close()
+    } catch {
+      case e: Exception => throw new JarPackaginException(e)
+    }
   }
 
 }
+
+/** Exception to indicate that the packaging process failed.
+  *
+  * @param cause the causing exception
+  */
+class JarPackaginException(cause: Exception) extends RuntimeException(cause)

src/main/scala/org/rosi_project/model_sync/generator/io/SModelFSWriter.scala

 package org.rosi_project.model_sync.generator.io
 
-import java.io.{BufferedInputStream, FileInputStream, FileOutputStream, PrintWriter}
+import java.nio.file.{Files, StandardCopyOption}
 import java.{io => jio}
-import java.net.URLClassLoader
-import java.nio.file.{CopyOption, Files, StandardCopyOption}
-import java.util.jar.{Attributes, JarEntry, JarOutputStream, Manifest}
 
 import org.rosi_project.model_sync.generator.ModelConfig
 import org.rosi_project.model_sync.generator.acr_model._
 import org.rosi_project.model_sync.generator.env.{FilesCompiler, JarPackager}
 
-import scala.reflect.io.{File, Path}
-import scala.tools.nsc.reporters.ConsoleReporter
-import scala.tools.nsc.{GenericRunnerSettings, Global, Settings}
-import scala.util.control.Breaks._
-import scala.reflect.io.Directory
+import scala.reflect.io.{Directory, File, Path}
 
 /** The `FSWriter` writes a [[SModel]] as a single compiled ''JAR'' file to the File System.
   *
@@ -40,12 +33,19 @@ class SModelFSWriter(
   println(s"Output dir is $outputDir")
 
   println("... Copying model images")
-  private val images = collectAllModelImages(modelCfg, currentDir)
-  private val imagesTargetDir = new jio.File(workingDir.toAbsolute.toString() + File.separator + "res")
+  private var images: List[jio.File] = _
+  private var imagesTargetDir: jio.File = _
+  try {
+    images = collectAllModelImages(modelCfg, currentDir)
+    imagesTargetDir = new jio.File(workingDir.toAbsolute.toString() + File.separator + "res")
     imagesTargetDir.mkdirs()
     images.foreach(img => {
       Files.copy(img.toPath, imagesTargetDir.toPath.resolve(img.getName), StandardCopyOption.REPLACE_EXISTING)
     })
+  } catch {
+    case e: Exception => throw new ModelImagePreparationException(e)
+  }
+
 
   override def visit(sModel: SModel): Unit = {
     println(s"... Wrote files (sources) $sFilesToCompile")
@@ -69,6 +69,7 @@ class SModelFSWriter(
   }
 
   override def visit(sClass: SClass): Unit = {
+    try {
       println(s"Writing class $sClass")
       val classNameWithPath = workingDir.toAbsolute.toString() + File.separator + pckg2Path(sClass.getPackage) + File.separator + s"${sClass.name}.scala"
       val writer = new SClassWriter(sClass)
@@ -78,6 +79,9 @@ class SModelFSWriter(
       classFile.jfile.getParentFile.mkdirs()
       classFile.writeAll(writer.stringify)
       sFilesToCompile ::= classFile
+    } catch {
+      case e: Exception => throw new ClassWritingException(e)
+    }
   }
 
   override def visit(sAttr: SAttribute): Unit = {
@@ -125,3 +129,15 @@ class SModelFSWriter(
   }
 
 }
+
+/** Exception to indicate that the model images may not be copied into the JAR.
+  *
+  * @param cause the causing exception
+  */
+class ModelImagePreparationException(cause: Exception) extends RuntimeException(cause)
+
+/** Exception to indicate that a class may not be written.
+  *
+  * @param cause the causing exception
+  */
+class ClassWritingException(cause: Exception) extends RuntimeException(cause)