Update MeshObjLoader.java

Exceptions redone.
Changed returning null to throwing exception.

MeshModel/src/main/java/cz/fidentis/analyst/mesh/io/MeshObjLoader.java

@@ -35,41 +35,30 @@ public class MeshObjLoader {
     /**
      * Loads data into MeshModel
      * @param is Input data stream with model
-     * @return Complete MeshModel or null if there is problem with data
-     * @throws IOException There was problem reading data stream
+     * @return Complete MeshModel
+     * @throws IOException Data are corrupted
      */
     public static MeshModel read(InputStream is) throws IOException {
-        MeshModel meshModel = null;
-        try {
-            final IOBJParser parser = new OBJParser();
-            final OBJModel model = parser.parse(is);
-            
-            if (model.getObjects().isEmpty()) {
-                return null;
-            }
-            OBJObject object = model.getObjects().get(0); 
-            meshModel = parseObjectToModel(model, object);
-            
-        } catch (IOException ex) {
-            throw new IOException("Cannot read requested stream", ex);
+        final IOBJParser parser = new OBJParser();
+        final OBJModel model = parser.parse(is);
+
+        if (model.getObjects().isEmpty()) {
+            throw new IOException("File doesn't contain any model");
         }
-        return meshModel;
+        OBJObject object = model.getObjects().get(0); 
+        return parseObjectToModel(model, object);
     }
     
     /**
      * Opens file and loads data into MeshModel
      * @param file File containing face to load into a MeshModel
-     * @return Complete MeshModel or null if there is problem with data
+     * @return Complete MeshModel
      * @throws FileNotFoundException Requested file was not found
      * @throws IOException There was problem with reading the file
      */
     public static MeshModel read(File file) throws FileNotFoundException, IOException {
         try (InputStream is = new FileInputStream(file)) {
             return read(is);
-        } catch (FileNotFoundException ex) {
-            throw new FileNotFoundException("File " + file.getName() + " not found");
-        } catch (IOException ex) {
-            throw new IOException("Cannot open file" + file.getName(), ex);
         }
     }    
     
@@ -77,16 +66,14 @@ public class MeshObjLoader {
      * Parse OBJObject into MeshModel
      * @param model Model is needed in future. It's holding data pools
      * @param object Object to parse. It corespond to our MeshModel
-     * @return Returns complete model or null if there is problem with data
+     * @return Returns complete model
+     * @throws IOException Data are corrupted
      */
-    private static MeshModel parseObjectToModel(OBJModel model, OBJObject object) {
+    private static MeshModel parseObjectToModel(OBJModel model, OBJObject object) throws IOException {
         MeshModel meshModel = new MeshModel();
         // Our facet = loader mesh, create and fill all facets
         for (OBJMesh mesh : object.getMeshes()) {
             MeshFacet meshFacet = parseMeshToFacet(model, mesh);
-            if (meshFacet == null) {
-                return null;
-            }
             meshModel.addChild(meshFacet);
         }
         return meshModel;
@@ -96,16 +83,14 @@ public class MeshObjLoader {
      * Parse OBJMesh into MeshFacet
      * @param model Model is needed in future. It's holding data pools
      * @param mesh Mesh to parse. It corespond to our MeshMacet
-     * @return Returns complete facet or null if there is problem with data
+     * @return Returns complete facet
+     * @throws IOException Data are corrupted
      */
-    private static MeshFacet parseMeshToFacet(OBJModel model, OBJMesh mesh) {
+    private static MeshFacet parseMeshToFacet(OBJModel model, OBJMesh mesh) throws IOException {
         MeshFacet meshFacet = new MeshFacet();
 
         for (OBJFace face : mesh.getFaces()) {
             MeshFace meshFace = parseFaceToFace(model, face, meshFacet);
-            if (meshFace == null) {
-                return null;
-            }
             meshFacet.addChild(meshFace);
         }
         return meshFacet;
@@ -116,14 +101,15 @@ public class MeshObjLoader {
      * @param model Model is needed in future. It's holding data pools
      * @param face Face to parse. It corespond to our MeshFace
      * @param meshFacet Facet is holding our data pools
-     * @return Returns complete face or null if there is problem with data
+     * @return Returns complete face
+     * @throws IOException Data are corrupted
      */
-    private static MeshFace parseFaceToFace(OBJModel model, OBJFace face, MeshFacet meshFacet) {
+    private static MeshFace parseFaceToFace(OBJModel model, OBJFace face, MeshFacet meshFacet) throws IOException {
         List<MeshPoint> facePoints = getPointsFromFace(model, face, meshFacet);
         MeshFace meshFace = new MeshFace();
 
         if (facePoints.size() != 3) {
-            return null;
+            throw new IOException("Data contains non-triangular face");
         }
         // Create edges
         for (int i = 1; i <= facePoints.size(); i++) {