Post on 02-Feb-2016
description
transcript
GWT In-depth
Explained by Rohit Ghatol(rohitsghatol@gmail.com)
http://pune-gtug.blogspot.com
Topics Covered
• Short Introduction to GWT• Architectural Overview• Simple Code Example• MVC Code Example• Server Communication using GWT – RPC• Open source Libraries
GWT Documentation Links
• Developer's Guide– Fundamentals – User Interfaces – Remote Procedure Calls – Unit Testing – Internationalization – JavaScript Native Interface (JSNI) – JRE Emulation – GWT Class API
E:\Work\GWT-Demo>set PATH=e:\worksoft\gwt-windows-1.4.60;%PATH%
E:\Work\GWT-Demo>projectCreator -eclipse SimpleDemoCreated directory E:\Work\GWT-Demo\srcCreated directory E:\Work\GWT-Demo\testCreated file E:\Work\GWT-Demo\.projectCreated file E:\Work\GWT-Demo\.classpath
E:\Work\GWT-Demo>applicationCreator -eclipse SimpleDemo com.gwt.demo.client.SimpleDemoCreated directory E:\Work\GWT-Demo\src\com\gwt\demoCreated directory E:\Work\GWT-Demo\src\com\gwt\demo\clientCreated directory E:\Work\GWT-Demo\src\com\gwt\demo\publicCreated file E:\Work\GWT-Demo\src\com\gwt\demo\SimpleDemo.gwt.xmlCreated file E:\Work\GWT-Demo\src\com\gwt\demo\public\SimpleDemo.htmlCreated file E:\Work\GWT-Demo\src\com\gwt\demo\client\SimpleDemo.javaCreated file E:\Work\GWT-Demo\SimpleDemo.launchCreated file E:\Work\GWT-Demo\SimpleDemo-shell.cmdCreated file E:\Work\GWT-Demo\SimpleDemo-compile.cmd
Demo GWT Project
• Site - http://code.google.com/p/gwt-simple-demo/• Download demo project from here
GWT Project Anatomy
GWT-Demo +src +com/gwt/demo SimpleDemo.gwt.xml - client SimpleDemo.java - public SimpleDemo.html
GWT Project Anatomy
SimpleDemo.gwt.xml
1. Module XML Definition File 2. Includes Project Dependencies3. Includes Entry Point4. Includes RPC Servlet Entry
SimpleDemo.java
1. This is the Entry Point2. Entry Point is like Main Method3. Widgets are added to RootPanel
SimpleDemo.html
1. This is the final deliverable HTML/JSP/ASP/PHP 2. Includes JS file for SimpleDemo3. Includes PlaceHolder Elements
Shuffle Box Example
Shuffle Box ExampleRootPanel
Shuffle Box Example
HorizontalPanel
Shuffle Box Example
VerticalPanel
Shuffle Box Example
Shuffle Box Example
Shuffle Box Examplenew ClickListener(){ public void onClick(Widget sender) { int leftIndex=leftListBox.getSelectedIndex(); if(leftIndex==-1){ Window.alert("Select an Item from Left List Box"); } else{ String item=leftListBox.getItemText(leftIndex); leftListBox.removeItem(leftIndex); rightListBox.addItem(item); } }}
Observable
# List observers+ addObserver(Observer observer)+ removeObserver(Observer observer)+ notifyObservers()
Observer<<Interface>>
+ update(Observable model)
Notify
Register/Unregister
View Source for Observable.java View Source for Observer.java
MVC Demo
MVC Demo
MVC Demo
# temperature+ setTemp(int temp)+int getTemp()
TempModel
# observers+ addObserver()+removeObserver()+ notifyObserver()
Observerable
FahrView CelsView ThermoView
update(Observable mode)
Observer
MVC Demo
# temperature+ setTemp(int temp)+int getTemp()
TempModel
# observers+ addObserver()+removeObserver()+ notifyObserver()
Observerable
FahrView CelsView ThermoView
update(Observable mode)
Observer
Renders
MVC Demo
# temperature+ setTemp(int temp)+int getTemp()
TempModel
# observers+ addObserver()+removeObserver()+ notifyObserver()
Observerable
FahrView CelsView ThermoView
update(Observable mode)
Observer
Register
MVC Demo
# temperature+ setTemp(int temp)+int getTemp()
TempModel
# observers+ addObserver()+removeObserver()+ notifyObserver()
Observerable
FahrView CelsView ThermoView
update(Observable mode)
Observer
User clicked increment button
Changes
MVC Demo
# temperature+ setTemp(int temp)+int getTemp()
TempModel
# observers+ addObserver()+removeObserver()+ notifyObserver()
Observerable
FahrView CelsView ThermoView
update(Observable mode)
Observer
Notifies
All the Views Update themselves using update() method
MVC Demo source files
• FahrView.java• CelsView.java• ThermoView.java• TempModel.java
RPC Demo
RPC Demo
RPC Demo
RPC Classes Explained
LocationService<<Interface>>
List getStates(String country)
LocationServiceImpl
List getStates(String country)
RemoteService<<Interface>>
List getStates(String country)
RemoteServiceServlet
LocationServiceAsync<<Interface>>
Void getStates(String country, AsyncCallback callback)
LocationServiceUtil
public static LocationServiceAsync getInstance()
GWT
MagicGlue
GWT Classes
RPC Classes Explained
AsyncCallback<<Interface>>
void onSuccess(Object result);
void onFailure(Throwable caught);
LocationServiceUtil Code
• Use GWT Glue to link LocationService and LocationServiceAsync classes
LocationServiceAsync serviceAsync = (LocationServiceAsync) GWT .create(LocationService.class);
• Set the Service’s Entry point (aka url)
((ServiceDefTarget) serviceAsync).setServiceEntryPoint(GWT.getModuleBaseURL()+ "/LocationService");
LocationServiceUtil Code
public class LocationServiceUtil { public static LocationServiceAsync createService() { LocationServiceAsync serviceAsync = (LocationServiceAsync) GWT .create(LocationService.class);
((ServiceDefTarget) serviceAsync).setServiceEntryPoint(GWT.getModuleBaseURL()+ "/LocationService"); return serviceAsync; }}
RPC Client Code
LocationServiceAsync serviceAsync = LocationServiceUtil.createService();serviceAsync.getStates(country, new AsyncCallback() {
public void onFailure(Throwable caught) {Window.alert("System Error!");
}
public void onSuccess(Object result) {List list = (List) result;statesListBoxModel.setEntries(list);
}});
RPC related Links
• Complete source code• LocationService.java• LocationServiceAsync.java• LocationServiceImpl.java• LocationServiceUtil.java• Client Code• RPC Tutorial
Extending Widgets for more events
onBrowserEvent(Event event)
Widget
FocusWidget
ListBox
Extending Widgets for more events
• Some Facts about ListBox widget– Following Listeners can be added• Change• Focus• Keyboard
– Extends FocusWidget which extends Widget– ListBox does not receive a DoubleClick event as it
never sinks it.
Extending Widgets for more events
• Some Facts about Widget class– A Widget needs to sink events in its constructor to
receive it– Widget class has an important method• void onBrowserEvent(Event event) which handles all
the events (eventually)
Extending Widgets for more events
• Some Facts about Widget class– If a Widget needs to receive a DoubleClick event it
needs to call sinkEvents(Event.ONDBLCLICK)
– If a Widget needs to handle this new DoubleClick event it needs to override onBrowserEvent method and handle this event
Extending Widgets for more events
# dblClickListenerCollection+ AdvListBox()# onBrowserEvent(Event event)
AdvListBox
ListBox
addDblClickListener()removeDblClickListener()fireDblClickEvent(Widget sender)
DblClickListenerCollection
ArrayList
Void onDoubleClick(Widget sender)
DblClickListener<<Interface>>
0..*
1
Extending Widgets for more events
public class AdvListBox extends ListBox { private DoubleClickListenerCollection dblClickListeners = new DoubleClickListenerCollection();
public AdvListBox() { this.sinkEvents(Event.ONDBLCLICK); }
public void onBrowserEvent(Event event) { super.onBrowserEvent(event); if(DOM.eventGetType(event)==Event.ONDBLCLICK){ dblClickListeners.fireDoubleClickEvent(this); } }
public void add(DoubleClickListener listener) { dblClickListeners.add(listener); }
public void remove(DoubleClickListener listener) { dblClickListeners.remove(listener); }}
AdvListBox.java Source
Extending Widgets for more eventsSource files• AdvListBox.java • AdvListBoxDemo.java • DoubleClickListener.java • DoubleClickListenerCollection.java
Open Source GWT Libraries Demos
• MyGWT – Many Rich UI widgets• GWT-DND – Meant for drag and drop
MyGWT
GWT-DND