My first reverse ajax application
icefaces, jakarta-ee, java, jsf, reverse-ajax
Solution
So many times it happens to me that i expend hours debugging and the reason of the bug was just the most simple thing.
Here i answer to my own question show how silly my mistake was:
Instead of using
javax.enterprise.context.ApplicationScoped
I should use
javax.faces.bean.ApplicationScoped
The reason is that i am not using Context and dependency injection, i am just using JSF managed beans.
Thanks to this i remembered it and i just refactored the imports, that's all Ctrl+Space doesn't like me :)
Problem
I want to learn about reverse ajax, I found a gadget called ICEPush and I thought it could be a good starting point. I am having trouble implementing a very simple application. I am following this tutorial, but instead of Tomcat, I am using Glassfish 3.1 and instead of Eclipse I am using NetBeans 7.1 I did exactly as it says in the tutorial, see my code. This is the page that will be the target of the Ajax push: ``` <html xmlns="http://www.w3.org/1999/xhtml" xmlns:h="http://java.sun.com/jsf/html" xmlns:f="http://java.sun.com/jsf/core"> <h:head> <title>Easy Ajax Push - Color</title> </h:head> <h:body> <h:dataTable value="#{messageBean.textList}" var="current"> <h:column> <h:outputText value="#{current.text}" style="color: #{current.color};"/> </h:column> </h:dataTable> <hr width="100%"/> <h:form> <h:panelGrid columns="4"> Choose a Color: <h:commandButton value="Red" action="#{colorBean.chooseColor}" style="color: white; background-color: red;"> <f:setPropertyActionListener target="#{colorBean.color}" value="red"/> </h:commandButton> <h:commandButton value="Blue" action="#{colorBean.chooseColor}" style="color: white; background-color: blue;"> <f:setPropertyActionListener target="#{colorBean.color}" value="blue"/> </h:commandButton> <h:commandButton value="Green" action="#{colorBean.chooseColor}" style="color: white; background-color: green;"> <f:setPropertyActionListener target="#{colorBean.color}" value="green"/> </h:commandButton> </h:panelGrid> </h:form> </h:body> </html> ``` Here are the 2 managed beans that are needed: ColorBean.java ``` @ManagedBean(name="colorBean") @ViewScoped public class ColorBean implements Serializable { private static final String PUSH_GROUP = "colorPage"; @ManagedProperty(value="#{messageBean}") private MessageBean messageBean; private String color = "black"; private String sessionId; public ColorBean() { PushRenderer.addCurrentSession(PUSH_GROUP); FacesContext fcontext = FacesContext.getCurrentInstance(); HttpSession session = (HttpSession)fcontext.getExternalContext().getSession(false); sessionId = session.getId(); } public void setMessageBean(MessageBean messageBean) { this.messageBean = messageBean; } public String getColor() { return color; } public void setColor(String color) { this.color = color; } public String chooseColor() { messageBean.addToList(sessionId, color); PushRenderer.render(PUSH_GROUP); return null; } } ``` MessageBean.java ``` @ManagedBean(name="messageBean") @ApplicationScoped public class MessageBean implements Serializable { private static final int MAX_SIZE = 25; private List<TextModel> textList = new ArrayList<TextModel>(0); public MessageBean() { } public List<TextModel> getTextList() { return textList; } public void setTextList(List<TextModel> textList) { this.textList = textList; } public void addToList(String sessionId, String color) { textList.add(makeTextModel(sessionId, color)); if (textList.size() > MAX_SIZE) { textList.clear(); } } private TextModel makeTextModel(String sessionId, String color) { return new TextModel("User with session ID of " + sessionId + " selected color \"" + color + "\".", color); } } ``` Also there is a simple pojo to represent the text being presented. TextModel.java ``` public class TextModel implements Serializable { private String text; private String color; public TextModel() { } public TextModel(String text, String color) { this.text = text; this.color = color; } public String getText() { return text; } public void setText(String text) { this.text = text; } public String getColor() { return color; } public void setColor(String color) { this.color = color; } public String toString() { return text; } } ``` I am using IceFaces version 3.0.1 and this is how my web.xml looks like: ``` <?xml version="1.0" encoding="UTF-8"?> <web-app version="3.0" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"> <context-param> <param-name>javax.faces.PROJECT_STAGE</param-name> <param-value>Development</param-value> </context-param> <context-param> <param-name>javax.faces.STATE_SAVING_METHOD</param-name> <param-value>server</param-value> </context-param> <context-param> <param-name>javax.faces.FACELETS_SKIP_COMMENTS</param-name> <param-value>true</param-value> </context-param> <context-param> <param-name>org.icefaces.mandatoryResourceConfiguration</param-name> <param-value/> </context-param> <context-param> <param-name>org.icefaces.ace.theme</param-name> <param-value>sam</param-value> </context-param> <context-param> <param-name>javax.faces.VALIDATE_EMPTY_FIELDS</param-name> <param-value>false</param-value> </context-param> <context-param> <param-name>com.icesoft.faces.gmapKey</param-name> <param-value>ABQIAAAADlu0ZiSTam64EKaCQr9eTRTOTuQNzJNXRlYRLknj4cQ89tFfpxTEqxQnVWL4k55OPICgF5_SOZE06A</param-value> </context-param> <servlet> <servlet-name>Faces Servlet</servlet-name> <servlet-class>javax.faces.webapp.FacesServlet</servlet-class> <load-on-startup>1</load-on-startup> </servlet> <servlet> <servlet-name>Resource Servlet</servlet-name> <servlet-class>com.icesoft.faces.webapp.CompatResourceServlet</servlet-class> <load-on-startup>1</load-on-startup> </servlet> <servlet-mapping> <servlet-name>Faces Servlet</servlet-name> <url-pattern>/faces/*</url-pattern> </servlet-mapping> <servlet-mapping> <servlet-name>Faces Servlet</servlet-name> <url-pattern>*.jsf</url-pattern> </servlet-mapping> <servlet-mapping> <servlet-name>Faces Servlet</servlet-name> <url-pattern>/icefaces/*</url-pattern> </servlet-mapping> <servlet-mapping> <servlet-name>Resource Servlet</servlet-name> <url-pattern>/xmlhttp/*</url-pattern> </servlet-mapping> <session-config> <session-timeout> 30 </session-timeout> </session-config> <welcome-file-list> <welcome-file>faces/index.xhtml</welcome-file> </welcome-file-list> </web-app> ``` This code gives me 3 problems: 1 - When i run the app and i click in some of the 3 buttons,get an exception that says that i cannot call one use one managed bean inside the other, because their scopes are not compatible: WARNING: queued exception javax.faces.FacesException: Unable to create managed bean colorBean. The following problems were found: - The scope of the object referenced by expression #{messageBean}, request, is shorter than the referring managed beans (colorBean) scope of view 2 - In the console all the time i see a message that says: WARNING: PWC4011: Unable to set request character encoding to UTF-8 from context /ReverseAjaxExample, because request parameters have already been read, or ServletRequest.getReader() has already been called 3 - If i change the @ApplicationScope to @ViewScope and the @ViewScope to @ApplicationScope in the managed beans, the first problem disappears and I can see how the application works, but the reverse ajax does not work, because other browsers do not display the changes. And also I always keep seeing the warning `PWC4011` in the console I never worked with reverse Ajax but I understand it from the theoretical point of view. I'll really appreciate it if you could give me a hand fixing this simple app.