hello Sir
I read yours eg and try to implement
but i got fail
can u give me this complete eg as a eclipse project
On Friday, March 28, 2008 10:11:50 PM UTC+5:30, neonleon wrote:
>
> Hello,
>
> I wanted to post a very simple example of GWT deferred binding as I
> had trouble initially grasping it.
>
> What this example will do is alert a message to the screen based on a
> meta property set in the html page.
>
>
> Here are the steps:
>
> 1. I am going to create java classes that will alert a message to the
> screen. Each one of these classes will implement an Alerter
> interface:
>
> package com.zedak.alerter.gwt.client.impl;
> ...
>
> public interface Alerter {
> public void alert();
> }
>
> 2. Here are my implementations of the above Alerter interface:
>
> package com.zedak.alerter.gwt.client.impl;
> ...
>
> public class HelloAlerterImpl implements Alerter{
> public void alert() {
> Window.alert("Hello!");
> }
> }
>
> public class GoodbyeAlerterImpl implements Alerter{
> public void alert() {
> Window.alert("Goodbye!");
> }
> }
>
> public class DefaultAlerterImpl implements Alerter{
> public void alert() {
> Window.alert("Default!");
> }
> }
>
> 3. I am going to create a property which will be utilized by GWT to
> determine which implementation my Alerter will use. I am going to
> define my properties in a seperate XML file than my main module to
> reduce clutter...
>
> Contents of Alerter-properties.gwt.xml:
>
> <module>
> <define-property name="alerter"
> values="hello,goodbye,default" /
> >
>
> <property-provider name="alerter">
> <![CDATA[
> var alerter =
> __gwt_getMetaProperty("alerter");
> if (alerter == null){
> alerter = "default";
> }
> return alerter;
> ]]>
> </property-provider>
> </module>
>
> The HTML will contain a meta property that will define which alerter
> to use. If no meta property exists, it will use the default.
>
> 4. I now will inherit the above module in my main module and define
> which Alerter implementation to use for each possible property.
>
> Contents of Alerter.gwt.xml:
>
> <module>
> ....
>
> <!-- Inherit the above module -->
> <inherits name="com.zedak.alerter.gwt.Alerter-properties"
> />
>
> <replace-with
> class="com.zedak.alerter.gwt.client.impl.HelloAlerterImpl">
> <when-type-is
> class="com.zedak.alerter.gwt.client.impl.AlerterImpl"/>
> <when-property-is name="alerter"
> value="hello"/>
> </replace-with>
>
> <replace-with
> class="com.zedak.alerter.gwt.client.impl.GoodbyeAlerterImpl">
> <when-type-is
> class="com.zedak.alerter.gwt.client.impl.AlerterImpl"/>
> <when-property-is name="alerter"
> value="goodbye"/>
> </replace-with>
>
> <replace-with
> class="com.zedak.alerter.gwt.client.impl.DefaultAlerterImpl">
> <when-type-is
> class="com.zedak.alerter.gwt.client.impl.AlerterImpl"/>
> <when-property-is name="alerter"
> value="default"/>
> </replace-with>
>
> <entry-point
> class='com.zedak.alerter.gwt.client.AlerterEntryPoint'/
> >
> ...
> </module>
>
> 5. Now lets create the EntryPoint class defined in the above XML,
> which will call the Alerter implementation based on the property
> value...
>
> package com.zedak.alerter.gwt.client;
> ...
>
> public class AlerterEntryPoint implements EntryPoint {
> public void onModuleLoad() {
> Alerter alerter = (Alerter)
> GWT.create(Alerter.class);
> alerter.alert();
> }
> }
>
> All this module will do is instantiate the appropriate Alerter and
> alert the message to the screen. You must use the GWT.create method
> to instatiate the Alerter class.
>
> 6. Finally, lets add the appropriate code to our Alerter.html page...
>
> <html>
> <head>
> <meta name='gwt:module' content='js/
> gwt=com.zedak.alerter.gwt.Alerter'/>
> <meta name='gwt:property'
> content='alerter=hello'/>
> </head>
> <body>
> <script language="javascript" src="/js/gwt/
> com.zedak.alerter.gwt.Alerter.nocache.js"/>
> </body>
> </html>
>
>
>
> When you load the Alerter.html file, you should see an alert dialog
> that states 'hello'.
>
> If you switch the property to this...
>
> <meta name='gwt:property' content='alerter=goodbye'/>
>
> You should see an alert dialog that states 'goodbye'.
>
> Removing the property entirely should display an alert dialog that
> states 'default'.
>
>
>
> I thought a super-simple example might be helpful for some people out
> there, and I hope that it is.
>
>
> -Leon
>
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