#967 initial support for dynamic components (wip)

- form rendering service to control field-component type mappings
- special <form-field> component with dynamic content creation based on
mapped types
- migrated <text> component to dynamic creation

ng2-components/ng2-activiti-form/src/services/form-rendering.service.ts

@@ -0,0 +1,57 @@
+/*!
+ * @license
+ * Copyright 2016 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 { Injectable, Type } from '@angular/core';
+
+import { TextWidget } from './../components/widgets/text/text.widget';
+
+@Injectable()
+export class FormRenderingService {
+
+    private types: { [key: string]: Type<{}> } = {
+        'text': TextWidget
+    };
+
+    getComponentType(fieldType: string): Type<{}> {
+        if (fieldType) {
+            return this.types[fieldType] || null;
+        }
+        return null;
+    }
+
+    setComponentType(fieldType: string, componentType: Type<{}>, override: boolean = false) {
+        if (!fieldType) {
+            throw new Error(`fieldType is null or not defined`);
+        }
+
+        if (!componentType) {
+            throw new Error(`componentType is null or not defined`);
+        }
+
+        let existing = this.types[fieldType];
+        if (existing && !override) {
+            throw new Error(`componentType is already mapped, use override option if you intend replacing existing mapping.`);
+        }
+
+        this.types[fieldType] = componentType;
+    }
+
+    constructor() {
+        this.setComponentType('xx', TextWidget);
+    }
+
+}