[Tapestry Wiki] Update of "InjectPropertyIntoASO" by ShingHingMan

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The following page has been changed by ShingHingMan:
http://wiki.apache.org/tapestry/InjectPropertyIntoASO

New page:
''' How to inject a property into an Application State Object (ASO) ? '''

In order to inject properties into an ASO, we implement a custom State``Object``Factory and define the method State``Object``Factory.create to create the ASO with the desired injected properties. We then use the above custom State``Object``Factory to create our ASO. The following example illustrates the above in detail. Suppose we have an ASO My``ASO with property messageHolder. We would like to create an My``ASO with the property messageHolder being injected by Hive``Mind.


{{{
package man.aso;

public class MyASO {

	private IMessageHolder messageHolder;

	public IMessageHolder getMessageHolder() {
		return messageHolder;
	}

	public void setMessageHolder(IMessageHolder message) {
		this.messageHolder = message;
	}
}
}}}

{{{
package man.aso;

public interface IMessageHolder {

	public String getMessage();

}
}}}

{{{
package man.aso;

public class HelloMessageHolder implements IMessageHolder{

	public String getMessage() {
		return "HelloMessage : Hello ";
	}

}

}}}


We shall inject Hell``oMessage``Holder into My``ASO. We now implement a custom State``Object``Factory called My``ASO``Factory.

{{{
package man.aso;

import org.apache.tapestry.engine.state.StateObjectFactory;

public class MyASOFactory implements StateObjectFactory{

	// To be injected by HiveMind
	private IMessageHolder messageHolder;
	
	// Contruct an MyASO with injected messageHolder
	public Object createStateObject() {	
		MyASO myASO = new MyASO();
		myASO.setMessageHolder(getMessageHolder());
		return myASO;
	}

	public IMessageHolder getMessageHolder() {		
		return messageHolder;
	}

	public void setMessageHolder(IMessageHolder message) {
		this.messageHolder = message;
	}

}

}}}


Note that the property My``ASO``Factory.messageHolder will be injected by Hive``Mind. The following configuration in Hive``Mind module descriptor hivemodule.xml does all the wiring.

{{{
hivemodule.xml

<service-point id="helloMessage" interface="man.aso.IMessageHolder">
        <invoke-factory>
        <construct class="man.aso.HelloMessageHolder"/>			
       </invoke-factory>		 		        
</service-point>
	
 <!-- This service creates an StateObjectFactory to create a MyASO.
         The property MyASO.messageHolder will be injected from service
         point helloMessage.	
   -->
<service-point id="myASOFactory" interface="man.aso.MyASOFactory">
    <invoke-factory>
         <construct class="man.aso.MyASOFactory">
		  <set-service property="messageHolder" service-id="helloMessage"/>
	 </construct>
   </invoke-factory>  
</service-point>
	
<contribution configuration-id="tapestry.state.ApplicationObjects">
    <state-object name="myASO" scope="session">
        <invoke-factory object="service:myASOFactory" />
     </state-object>
</contribution>

}}}


The above will result in an ASO my``ASO being created with property messageHolder set to Hello``Message``Holder. 

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