net.bootsfaces.component.ajax.AJAXBroadcastComponent Maven / Gradle / Ivy
package net.bootsfaces.component.ajax;
import javax.el.ELContext;
import javax.el.ExpressionFactory;
import javax.el.MethodExpression;
import javax.el.PropertyNotFoundException;
import javax.el.ValueExpression;
import javax.faces.FacesException;
import javax.faces.application.ProjectStage;
import javax.faces.component.UIComponent;
import javax.faces.component.UIComponentBase;
import javax.faces.context.FacesContext;
import javax.faces.event.AbortProcessingException;
import javax.faces.event.ActionEvent;
import javax.faces.event.ActionListener;
import javax.faces.event.FacesEvent;
public class AJAXBroadcastComponent extends UIComponentBase {
private UIComponent source;
public AJAXBroadcastComponent(UIComponent source) {
this.source = source;
}
/**
*
* In addition to to the default {@link UIComponent#broadcast} processing,
* pass the {@link ActionEvent} being broadcast to the method referenced by
* actionListener (if any), and to the default
* {@link ActionListener} registered on the
* {@link javax.faces.application.Application}.
*
*
* @param event
* {@link FacesEvent} to be broadcast
*
* @throws AbortProcessingException
* Signal the JavaServer Faces implementation that no further
* processing on the current event should be performed
* @throws IllegalArgumentException
* if the implementation class of this {@link FacesEvent} is not
* supported by this component
* @throws NullPointerException
* if event is null
*/
@SuppressWarnings("deprecation")
public void broadcast(FacesEvent event) throws AbortProcessingException {
// Perform standard superclass processing
source.broadcast(event);
if (event instanceof BootsFacesAJAXEvent) {
Object result = executeAjaxCalls(FacesContext.getCurrentInstance(),
((BootsFacesAJAXEvent) event).getJsCallback());
// if (result != null) {
// System.out.println("Redirection has not yet been implemented.");
// }
}
}
/**
* Evaluates an EL expression into an object.
*
* @param p_expression
* the expression
* @throws PropertyNotFoundException
* if the attribute doesn't exist at all (as opposed to being
* null)
* @return the object
*/
public static ValueExpression evalAsValueExpression(String p_expression) throws PropertyNotFoundException {
FacesContext context = FacesContext.getCurrentInstance();
ExpressionFactory expressionFactory = context.getApplication().getExpressionFactory();
ELContext elContext = context.getELContext();
ValueExpression vex = expressionFactory.createValueExpression(elContext, p_expression, Object.class);
return vex;
}
/**
* Evaluates an EL expression into an object.
*
* @param p_expression
* the expression
* @throws PropertyNotFoundException
* if the attribute doesn't exist at all (as opposed to being
* null)
* @return the object
*/
public static MethodExpression evalAsMethodExpression(String p_expression) throws PropertyNotFoundException {
FacesContext context = FacesContext.getCurrentInstance();
ExpressionFactory expressionFactory = context.getApplication().getExpressionFactory();
ELContext elContext = context.getELContext();
MethodExpression mex = expressionFactory.createMethodExpression(elContext, p_expression, Object.class, new Class[0]);
return mex;
}
/**
* Execute the ajax call when ajax syntax was found ajax:
*
* @param context
* @param command
* @return
*/
private Object executeAjaxCalls(FacesContext context, String command) {
Object result = null;
int pos = command.indexOf("ajax:");
while (pos >= 0) { // the command may contain several AJAX and
// JavaScript calls, in arbitrary order
String el = command.substring(pos + "ajax:".length());
if (el.contains("javascript:")) {
int end = el.indexOf("javascript:");
el = el.substring(0, end);
}
el = el.trim();
while (el.endsWith(";")) {
el = el.substring(0, el.length() - 1).trim();
}
if (context.isProjectStage(ProjectStage.Development)) {
checkELSyntax(el, context.getELContext());
}
ValueExpression vex = evalAsValueExpression("#{" + el + "}");
try {
result = vex.getValue(context.getELContext());
} catch (javax.el.PropertyNotFoundException ex) {
MethodExpression mex = evalAsMethodExpression("#{" + el + "}");
result = mex.invoke(context.getELContext(), null);
}
// look for the next AJAX call (if any)
pos = command.indexOf("ajax:", pos + 1);
}
return result;
}
/**
* Evaluate the expression syntax
*
* @param el
* @param context
*/
private void checkELSyntax(String el, ELContext context) {
int pos = el.indexOf('.');
if (pos<0) {
throw new FacesException("The EL expression doesn't contain a method call: " + el);
}
int end = el.indexOf('(');
if (end < 0)
end = el.length();
if (el.indexOf('[') >= 0)
end = Math.min(end, el.indexOf('['));
while (pos < end) {
String object = el.substring(0, pos);
ValueExpression vex = evalAsValueExpression("#{" + object + "}");
vex.getValue(context);
Object result = vex.getValue(context);
if (result == null) {
System.out.println("Please check your EL expression - intermediate term " + object + " is null");
}
pos = el.indexOf('.', pos + 1);
if (pos < 0)
break;
}
}
@Override
public String getFamily() {
// TODO Auto-generated method stub
return null;
}
}