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Wednesday, 2 January 2013

Invoke ADF Table Selection Listener, custom selection listener for af:table


Sometimes we need to define our own selection listener for adf table, or we have to perform some operation on row selection in af:table.

We can do this by defining custom selection listener for table in Managed bean.
In this tutorial i am showing a popup on table row selection , Here i am using Employees table of HR Schema
  • Prepare model and ViewController for Employees table and drag table in your page. Now select table and go to property Inspector , you will see its default selection listener 

Selection Listener of af:table


  • Now define your own (custom) selection listener for this table in your managed bean
Create custom selection listener in managed bean to handle selection event on af:table

  • Now write this code snippet on that custom selection listener,this code invokes its default listener and get the selected row. first you have to invoke its default listener that is
#{bindings.Employees1.collectionModel.makeCurrent}




    public void empTableSelectionListener(SelectionEvent selectionEvent) {
        ADFUtil.invokeEL("#{bindings.Employees1.collectionModel.makeCurrent}", new Class[] {SelectionEvent.class},
                         new Object[] { selectionEvent });
        // get the selected row , by this you can get any attribute of that row
        Row selectedRow =
            (Row)ADFUtil.evaluateEL("#{bindings.Employees1Iterator.currentRow}"); // get the current selected row
        //to show popup, you can write your logic here , what you wanna do
        showPopup(empPopup, true);
    }

  • you have to import these packages in order to invoke selection listener

import org.apache.myfaces.trinidad.event.SelectionEvent;
import org.apache.myfaces.trinidad.render.ExtendedRenderKitService;
import org.apache.myfaces.trinidad.util.Service;


  • In above code snippet ADFUtil is an utility class that contains methods for invoking EL (Expression language), so you have to make a Java class named ADFUtil in same package as bean
import java.util.Map;

import javax.el.ELContext;
import javax.el.ExpressionFactory;
import javax.el.MethodExpression;
import javax.el.ValueExpression;

import javax.faces.context.FacesContext;

import oracle.adf.model.BindingContext;
import oracle.adf.model.DataControlFrame;


/**
 * Provides various utility methods that are handy to
 * have around when working with ADF.
 */

public class ADFUtil {

/**
* When a bounded task flow manages a transaction (marked as requires-transaction,.
* requires-new-transaction, or requires-existing-transaction), then the
* task flow must issue any commits or rollbacks that are needed. This is
* essentially to keep the state of the transaction that the task flow understands
* in synch with the state of the transaction in the ADFbc layer.
*
* Use this method to issue a commit in the middle of a task flow while staying
* in the task flow.
*/

public static void saveAndContinue() {
Map sessionMap =
FacesContext.getCurrentInstance().getExternalContext().getSessionMap();
BindingContext context =
(BindingContext)sessionMap.get(BindingContext.CONTEXT_ID);
String currentFrameName = context.getCurrentDataControlFrame();
DataControlFrame dcFrame =
context.findDataControlFrame(currentFrameName);

dcFrame.commit();
dcFrame.beginTransaction(null);
}

/**
* Programmatic evaluation of EL.
*
* @param el EL to evaluate
* @return Result of the evaluation
*/

public static Object evaluateEL(String el) {
FacesContext facesContext = FacesContext.getCurrentInstance();
ELContext elContext = facesContext.getELContext();
ExpressionFactory expressionFactory =
facesContext.getApplication().getExpressionFactory();
ValueExpression exp =
expressionFactory.createValueExpression(elContext, el,
Object.class);

return exp.getValue(elContext);
}

/**
* Programmatic invocation of a method that an EL evaluates to.
* The method must not take any parameters.
*
* @param el EL of the method to invoke
* @return Object that the method returns
*/

public static Object invokeEL(String el) {
return invokeEL(el, new Class[0], new Object[0]);
}

/**
* Programmatic invocation of a method that an EL evaluates to.
*
* @param el EL of the method to invoke
* @param paramTypes Array of Class defining the types of the parameters
* @param params Array of Object defining the values of the parametrs
* @return Object that the method returns
*/

public static Object invokeEL(String el, Class[] paramTypes,
Object[] params) {
FacesContext facesContext = FacesContext.getCurrentInstance();
ELContext elContext = facesContext.getELContext();
ExpressionFactory expressionFactory =
facesContext.getApplication().getExpressionFactory();
MethodExpression exp =
expressionFactory.createMethodExpression(elContext, el,
Object.class, paramTypes);

return exp.invoke(elContext, params);
}

/**
* Sets a value into an EL object. Provides similar functionality to
* the <af:setActionListener> tag, except the from is
* not an EL. You can get similar behavior by using the following...

* setEL(to, evaluateEL(from))
*
* @param el EL object to assign a value
* @param val Value to assign
*/

public static void setEL(String el, Object val) {
FacesContext facesContext = FacesContext.getCurrentInstance();
ELContext elContext = facesContext.getELContext();
ExpressionFactory expressionFactory =
facesContext.getApplication().getExpressionFactory();
ValueExpression exp =
expressionFactory.createValueExpression(elContext, el,
Object.class);

exp.setValue(elContext, val);
}
}



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