[ADF-4068] ProcessServices - add description validation on Edit Task Form (#4366)

* [ADF-4068] StartTaskComponent - fix name and description empty space validation

* [ADF-4068] StartTakComponent - add unit test

* [ADF-4068] ProcessServices - add description validaton on edit task form

* [ADF-4068] ProcessServies - fix build issue

lib/process-services-cloud/src/lib/i18n/en.json

@@ -200,6 +200,9 @@
       "DESCRIPTION_DEFAULT": "No description",
       "FORM_NAME": "Form Name",
       "FORM_NAME_DEFAULT": "No form"
+    },
+    "FORM_VALIDATION": {
+        "INVALID_FIELD": "Enter a different value"
     }
   }
 }

lib/process-services/task-list/components/task-header.component.ts

@@ -29,6 +29,7 @@ import {
 } from '@alfresco/adf-core';
 import { TaskDetailsModel } from '../models/task-details.model';
 import { TaskListService } from './../services/tasklist.service';
+import { TaskDescriptionValidator } from '../validators/task-description.validator';
 
 @Component({
     selector: 'adf-task-header',
@@ -168,7 +169,8 @@ export class TaskHeaderComponent implements OnChanges, OnInit {
                     key: 'description',
                     default: this.translationService.instant('ADF_TASK_LIST.PROPERTIES.DESCRIPTION_DEFAULT'),
                     multiline: true,
-                    editable: true
+                    editable: true,
+                    validators: [new TaskDescriptionValidator()]
                 }
             ),
             new CardViewTextItemModel(

lib/process-services/task-list/validators/task-description.validator.ts

@@ -0,0 +1,29 @@
+/*!
+ * @license
+ * Copyright 2019 Alfresco Software, Ltd.
+ *
+ * Licensed 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.
+ */
+
+import { CardViewItemValidator } from '@alfresco/adf-core';
+
+export class TaskDescriptionValidator implements CardViewItemValidator {
+
+    message: string = 'ADF_CLOUD_TASK_HEADER.FORM_VALIDATION.INVALID_FIELD';
+
+    isValid(value: any): boolean {
+        const isWhitespace = (value || '').trim().length === 0;
+        return value.length === 0 || !isWhitespace;
+    }
+
+}