Initial prototype of Observable object

BCL.csproj

@@ -152,6 +152,15 @@
     <TypeScriptCompile Include="text\text.ios.ts">
       <DependentUpon>text.d.ts</DependentUpon>
     </TypeScriptCompile>
+    <TypeScriptCompile Include="ui\core\proxy.ts" />
+    <TypeScriptCompile Include="ui\text-view\text-view.android.ts">
+      <DependentUpon>text-view.d.ts</DependentUpon>
+    </TypeScriptCompile>
+    <TypeScriptCompile Include="ui\text-view\text-view.common.ts" />
+    <TypeScriptCompile Include="ui\text-view\text-view.d.ts" />
+    <TypeScriptCompile Include="ui\text-view\text-view.ios.ts">
+      <DependentUpon>text-view.d.ts</DependentUpon>
+    </TypeScriptCompile>
     <TypeScriptCompile Include="utils\module-merge.ts" />
     <TypeScriptCompile Include="utils\utils_android.ts" />
     <TypeScriptCompile Include="utils\utils_ios.ts" />

ui/core/observable.ts

@@ -1 +1,112 @@
- 
+export enum ChangePhase {
+    Changing,
+    Changed
+}
+
+export interface ChangeData {
+    eventName: string;
+    sender: Observable;
+    phase?: ChangePhase;
+}
+
+export interface PropertyChangeData extends ChangeData {
+    propertyName: string;
+    oldValue: any;
+    newValue: any;
+    cancel?: boolean;
+}
+
+export class Observable {
+    public static propertyChangeEvent = "propertyChange";
+    private _observers = {};
+
+    // true to track the Changing phase, false otherwise
+    private _trackChanging = false;
+
+    public bind(eventName: string, callback: (data: ChangeData) => void) {
+        this.verifyCallback(callback);
+        var list = this.getEventList(eventName, true);
+        list.push(callback);
+    }
+
+    public setProperty(name: string, value: any) {
+        // TODO: Parameter validation
+
+        if (!(name in this._observers)) {
+            // no observers to notify for the PropertyChange event
+            return;
+        }
+
+        // create data for the change
+        var data: PropertyChangeData = {
+            eventName: Observable.propertyChangeEvent,
+            propertyName: name,
+            sender: this,
+            oldValue: this[name],
+            newValue: value,
+            cancel: false
+        };
+
+        if (this._trackChanging) {
+            data.phase = ChangePhase.Changing;
+            this.notifyObservers(data);
+            if (data.cancel) {
+                // change is canceled by an observer
+                // TODO: define some priority, e.g. if someone cancels the change should others be able to override this cancelation?
+                return;
+            }
+        }
+
+        data.phase = ChangePhase.Changed;
+        this.notifyObservers(data);
+
+        this.setPropertyCore(data);
+    }
+
+    public getProperty(name: string): any {
+        return this[name];
+    }
+
+    /**
+    * This method is intended to be overriden by inheritors to specify additional 
+    */
+    public setPropertyCore(data: PropertyChangeData) {
+        // get the new value from the data since some observer may have it modified - e.g. validation scenario
+        this[data.eventName] = data.newValue;
+    }
+
+    private getEventList(eventName: string, createIfNeeded?: boolean): Array<(data: ChangeData) => void> {
+        if (!eventName) {
+            throw new TypeError("EventName must be valid string.");
+        }
+
+        var list = <Array<(data: ChangeData) => void>>this._observers[eventName];
+        if (!list && createIfNeeded) {
+            list = new Array<(data: ChangeData) => void>();
+            this._observers[eventName] = list;
+        }
+
+        return list;
+    }
+
+    private verifyCallback(callback: any) {
+        if (!callback || typeof callback !== "function") {
+            throw new TypeError("Callback must be a valid function.");
+        }
+    }
+
+    // The method will return true if the change is accepted, false otherwise
+    private notifyObservers(data: ChangeData) {
+        var observers = this.getEventList(data.eventName);
+        if (!observers) {
+            return;
+        }
+
+        var i,
+            callback;
+        for (i = 0; i < observers.length; i++) {
+            callback = observers[i];
+            callback(data);
+        }
+    }
+}

ui/core/proxy.ts

@@ -0,0 +1,12 @@
+import observable = require("ui/core/observable"); 
+
+export class ProxyObject extends observable.Observable {
+    public setPropertyCore(data: observable.PropertyChangeData) {
+        super.setPropertyCore(data);
+        this.setNativeProperty(data);
+    }
+
+    public setNativeProperty(data: observable.PropertyChangeData) {
+        // TODO:
+    }
+}

ui/core/view.ts

@@ -1 +1,5 @@
- 
+import proxy = require("ui/core/proxy");  
+
+export class View extends proxy.ProxyObject {
+
+}

ui/text-view/text-view.android.ts

@@ -0,0 +1,21 @@
+import observable = require("ui/core/observable");
+import view = require("ui/core/view");
+
+export class TextView extends view.View {
+    public android: android.widget.TextView;
+
+    get text(): string {
+        if (this.android) {
+            return this.android.getText().toString();
+        }
+
+        return undefined;
+    }
+    set text(value: string) {
+
+    }
+
+    public setNativeProperty(data: observable.PropertyChangeData) {
+        // TODO:
+    }
+} 

ui/text-view/text-view.common.ts

@@ -0,0 +1,14 @@
+import observable = require("ui/core/observable");
+import view = require("ui/core/view");
+
+export class TextView extends view.View {
+    public static textProperty = "text";
+
+    get text(): string {
+        return this.getProperty(TextView.textProperty);
+    }
+
+    public setNativeProperty(data: observable.PropertyChangeData) {
+        // TODO:
+    }
+} 

ui/text-view/text-view.d.ts

@@ -0,0 +1 @@
+

ui/text-view/text-view.ios.ts

@@ -0,0 +1,5 @@
+import view = require("ui/core/view");
+
+export class TextView extends view.View {
+
+}