Fixes missing required message

backend/src/main/resources/i18n/messages_en.properties

@@ -401,6 +401,7 @@ message.org-incomplete=These three fields must all be entered if any single fiel
 message.type-required=Missing required property: Type
 message.match-required=Missing required property: Match
 message.value-required=Missing required property: Value
+message.required=Field is required.
 
 message.conflict=Conflict
 message.data-version-contention=Data Version Contention

ui/src/app/metadata/domain/model/wizards/metadata-source-base.ts

@@ -60,6 +60,28 @@ export class MetadataSourceBase implements Wizard<MetadataResolver> {
     }
 
     getValidators(entityIdList: string[]): { [key: string]: any } {
+        const checkRequiredChild = (value, property, form) => {
+            if (!value) {
+                return {
+                    code: 'REQUIRED',
+                    path: `#${property.path}`,
+                    message: `message.required`,
+                    params: [value]
+                };
+            }
+            return null;
+        };
+        const checkRequiredChildren = (value, property, form) => {
+            let errors;
+            Object.keys(value).forEach((item, index, all) => {
+                const error = checkRequiredChild(item, { path: `${index}` }, form);
+                if (error) {
+                    errors = errors || [];
+                    errors.push(error);
+                }
+            });
+            return errors;
+        };
         const checkOrg = (value, property, form) => {
             const org = property.parent;
             const orgValue = org.value || {};

ui/src/app/schema-form/widget/string/string.component.ts

@@ -1,22 +1,41 @@
-import { Component } from '@angular/core';
+import { Component, AfterViewInit, OnDestroy } from '@angular/core';
 import { StringWidget } from 'ngx-schema-form';
 import { Validators } from '@angular/forms';
 import { SchemaService } from '../../service/schema.service';
+import { startWith } from 'rxjs/operators';
+import { Subscription } from 'rxjs';
 
 @Component({
     selector: 'custom-string',
     templateUrl: `./string.component.html`,
     styleUrls: ['../widget.component.scss']
 })
-export class CustomStringComponent extends StringWidget {
+export class CustomStringComponent extends StringWidget implements AfterViewInit, OnDestroy {
+
+    errorSub: Subscription;
 
     constructor(
         private widgetService: SchemaService
     ) {
         super();
     }
 
+    ngAfterViewInit(): void {
+        super.ngAfterViewInit();
+        this.errorSub = this.control.valueChanges.pipe(startWith(this.control.value)).subscribe(v => {
+            if (!v && this.required && this.errorMessages.some(msg => !!msg.toLowerCase().match('required').length)) {
+                this.errorMessages.push('message.required');
+            }
+        });
+    }
+
+    ngOnDestroy(): void {
+        this.errorSub.unsubscribe();
+    }
+
     get required(): boolean {
-        return this.widgetService.isRequired(this.formProperty);
+        const req = this.widgetService.isRequired(this.formProperty);
+
+        return req;
     }
 }