Handle NotePathAlreadyExistsException with ConflictException

- Introduced `ConflictException` for detailed error response.
- Added handling of `NotePathAlreadyExistsException` in `NotebookRestApi`.

Author: tbonelee

zeppelin-server/src/main/java/org/apache/zeppelin/rest/NotebookRestApi.java

@@ -46,9 +46,11 @@
 import org.apache.zeppelin.notebook.Notebook;
 import org.apache.zeppelin.notebook.Paragraph;
 import org.apache.zeppelin.notebook.AuthorizationService;
+import org.apache.zeppelin.notebook.exception.NotePathAlreadyExistsException;
 import org.apache.zeppelin.notebook.repo.NotebookRepoWithVersionControl;
 import org.apache.zeppelin.notebook.scheduler.SchedulerService;
 import org.apache.zeppelin.rest.exception.BadRequestException;
+import org.apache.zeppelin.rest.exception.ConflictException;
 import org.apache.zeppelin.rest.exception.ForbiddenException;
 import org.apache.zeppelin.rest.exception.NoteNotFoundException;
 import org.apache.zeppelin.rest.exception.ParagraphNotFoundException;
@@ -486,7 +488,15 @@ public Response exportNote(@PathParam("noteId") String noteId) throws IOExceptio
   @ZeppelinApi
   public Response importNote(@QueryParam("notePath") String notePath, String noteJson) throws IOException {
     String noteId = notebookService.importNote(notePath, noteJson, getServiceContext(),
-            new RestServiceCallback<>());
+            new RestServiceCallback<>() {
+              @Override
+              public void onFailure(Exception ex, ServiceContext context) throws IOException {
+                if (ex instanceof NotePathAlreadyExistsException) {
+                  ex = new ConflictException(ex.getMessage());
+                }
+                super.onFailure(ex, context);
+              }
+            });
     return new JsonResponse<>(Status.OK, "", noteId).build();
   }
 
@@ -512,7 +522,15 @@ public Response createNote(String message) throws IOException {
             defaultInterpreterGroup,
             request.getAddingEmptyParagraph(),
             getServiceContext(),
-            new RestServiceCallback<>());
+            new RestServiceCallback<>() {
+              @Override
+              public void onFailure(Exception ex, ServiceContext context) throws IOException {
+                if (ex instanceof NotePathAlreadyExistsException) {
+                  ex = new ConflictException(ex.getMessage());
+                }
+                super.onFailure(ex, context);
+              }
+            });
     return notebook.processNote(noteId,
       note -> {
         AuthenticationInfo subject = new AuthenticationInfo(authenticationService.getPrincipal());
@@ -613,6 +631,13 @@ public void onSuccess(Note note, ServiceContext context) throws IOException {
                 notebookServer.broadcastNote(note);
                 notebookServer.broadcastNoteList(context.getAutheInfo(), context.getUserAndRoles());
               }
+              @Override
+              public void onFailure(Exception ex, ServiceContext context) throws IOException {
+                if (ex instanceof NotePathAlreadyExistsException) {
+                  ex = new ConflictException(ex.getMessage());
+                }
+                super.onFailure(ex, context);
+              }
             });
     return new JsonResponse<>(Status.OK, "").build();
   }

zeppelin-server/src/main/java/org/apache/zeppelin/rest/exception/ConflictException.java

@@ -0,0 +1,34 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.zeppelin.rest.exception;
+
+import jakarta.ws.rs.WebApplicationException;
+import jakarta.ws.rs.core.Response;
+import org.apache.zeppelin.utils.ExceptionUtils;
+
+/**
+ * ConflictException handler for WebApplicationException
+ */
+public class ConflictException extends WebApplicationException {
+  private static Response conflictJson(String message) {
+    return ExceptionUtils.jsonResponseContent(Response.Status.CONFLICT, message);
+  }
+
+  public ConflictException(String message) {
+    super(conflictJson(message));
+  }
+}

zeppelin-server/src/main/java/org/apache/zeppelin/service/NotebookService.java

@@ -385,7 +385,9 @@ public String importNote(String notePath,
           callback.onSuccess(note, context);
           return note.getId();
         });
-
+    } catch (NotePathAlreadyExistsException e) {
+      callback.onFailure(new NotePathAlreadyExistsException("Fail to import note: " + e.getMessage(), e), context);
+      return null;
     } catch (IOException e) {
       callback.onFailure(new IOException("Fail to import note: " + e.getMessage(), e), context);
       return null;

zeppelin-zengine/src/main/java/org/apache/zeppelin/notebook/exception/NotePathAlreadyExistsException.java

@@ -26,4 +26,8 @@ public NotePathAlreadyExistsException(final String message) {
         super(message);
     }
 
+    public NotePathAlreadyExistsException(final String message, final Throwable cause) {
+        super(message, cause);
+    }
+
 }