Viewing this example of pagination [URL] and other similar beans for pagination, why do they do these beans view scoped? These beans dont contain any properties for a form so they could be application scoped, right?
View RepliesI am trying to restrict the number of views in JSF 2.0.2 using
<context-param>
<param-name>org.apache.myfaces.NUMBER_OF_VIEWS_IN_SESSION</param-name>
<param-value>5</param-value>
</context-param>
In my case my managed bean is View Scoped and it supports a UI page which has multiple forms and each form is submitted as AJAX POST request.
As per the statndard, setting restriction to 5 should create 5 views and after that based on LRU algorithm the oldest views should get deleted if 6th views is created.
Therefore any action on the oldest view will throw the ViewExpiredException and i simply redirect the user to view expired page.
1) When i set the restriction to 5 views, i open 4 tabs with 3 forms each.
2) I submit the 3 forms on first tab everything works fine.
3) As soon as I go to 2nd tab and submit the first form thr, i get view expired exception
4) It seems I am exceeding the number of views I mentioned in web.xml
I want to know :
1) Does every AJAX POST submit itself creates a view ?
2) How I can count the number of views created in a session ?
3)Can i force expiry of a view in JSF 2.0.2 while the session is still alive ?
4) Normally JSF 2.0.2 session cachces the views. Lets assume session is alive the entire day but a view was created in morning at 9:00 AM and is not used again the entire day. Assuming that session doesn't reaches the max number of views it can save in entire day, will the view created in morning expire on its own after certain interval of time ? If not , can we still force its expiry while keeping the session alive ?
A distributed application consists of modules which run on different machines. How is this possible? Does it have any link with the public modifier?
View Replies View RelatedI have a managed bean for a form. I map the fields filled in the form with managed bean properties. when I submit the form and click new form , values from the previous form submitted gets displayed in the input fields. I used the scope of the from bean to session. what should be its scope so that values should be destroyed after I submit the form .For every new form ,new bean has to be initialized. On submit I navigate to another bean with session scope.
View Replies View RelatedI'm just wondering why variables in interface can't be instance scope?
interface Test{
int a;
}
And then
Test test = new TestImpl();
test.a=13;
Yes, it violates OO, but I don't see why this is not possible? Since interface is not an implementation, therefore it can;t have any instance scope variable. I can't find the correlation of interface being abstract and being able to hold instance scope variable. There's gotta be another reason. I'm just curious about any programmatic limitation, not deliberate design constraint. the example of programmatic limitation is like when Java forbids multiple inheritance since when different parents have the exact same method, then the child will have trouble determining which method to run at runtime.
I want to initialize my servlet based on the scope of my application.
For example, I have multiple admins with their respective email address.
I want to perform action within my servlet based on the given environment.
Would this be the right approach, if I set the admin email addresses in my web.xml as init-param:
<servlet>
<servlet-name>ServletName</servlet-name>
<servlet-class>com.mkyong.ServletDemo</servlet-class>
<init-param>
<param-name>admin1</param-name>
[Code] .....
Now if I am in the admin 1 environment, I would initialize my servlet with request parameter admin=1 and the servlet should load email address of admin 1 and similarly when in the environment 2, should load the servlet with admin 2.
call environment 1:
/servlet/Demo?admin=1
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws IOException{
[Code] .....
I could do the same by putting the email address of the respective admin as request param value, but i don't want to the email address to appear in the url.
I have a hyperlink say,
[URL]
now, i want to access a managed bean's method to execute a service call related to the code embedded in the hyperlink.
My Managed bean
@ManagedBean(name="details")
@SessionScoped
public class XXXX extends Bean implements Serializable{
public XXXX(){...... }
public myMethod(..){
service.getDataRelatedToHyperlinkCode(....passing code here to fetch details from DB)
}
}
if i use postConstruct annotation it is getting executed only once since it is a session scope. and point to be noted is i cannot use viewscope and requestscope.
I have an issue with variables/attributes scope inside a jsp tag file.
In short, I have a tag with an attribute named "id". If the page using my tag has a variable called "id" (maybe coming from the spring model) and I call my tag WITHOUT specifying the id attribute, inside my tag I still can acces to the "id" attribute that was defined in the page but I don't want this behavior; if the tag is called without the "id" attribute then it should defaults to empty/null.
Example:
print.tag
<%@ attribute name="id" required="false" type="java.lang.String" %>
id=${id}
site.jsp
(...)
The id is: ${id} // <- Prints 'X'
<my:print /> <- Prints 'X' ! I want it to not print anything in that case
<my:print id="Y"/> <- Prints 'Y'
(...)
What I want is to have the tag attributes live only in the tag, without having any knowledge of any variable outside of the tag itself. Is it possible?
My current workaround is to remove the "id" attribute, enable dynamic attributes and with a scriptlet search in the dynamic attributes map for the "id" and save it in a variable with a different name (e.g. "__id").
So I've been working on a music player in android studio and I've created two java classes. One for Main Start Screen(StartScreen.Java) and one for the main player (player.Java). I have an onClicl event associated with a button as shown below.
public void onclick(View view) {
Intent detailIntent = new Intent(this, main_player.class);
startActivity(detailIntent);
}
The code for the second Java Class is as below. There is nothing in the java class as for now.
package com.example.musicplayer.app;
import android.app.Activity;
import android.os.Bundle;
public class main_player extends Activity {
protected void onCreate(Bundle savedInstanceState) {
[Code] .....
Where is the actual mistake because the app works fine until i click the button that is suppose to take me to the main player screen?
I am building a room management system in Java (Netbeans) and Ms Access. The jasper report is only showing code (source view) instead of design view. The GUI JFrame and Login JFrame are not displaying records in the database and the buttons are not working. Also the labels and text fields are not neatly arranged. The connection to the database is not displaying records.
Connection to the database. COIRMS.java
package Login;
import java.sql.*;
public class COIRMS {
Connection con;
Statement st;
ResultSet rs;
public COIRMS ()
[Code] ....
I am learning JAVA and understanding some of its specific oddities. For example I notice that JAVA loves instances but not variables.
In Python:
x = 1
y = 2
print(x,y)
yields (1,2)
then I do y = x and print
getting (1,1)
This makes sense to me since x and y are variables and thats how variables work. In JAVA I notice this script:
public class TESTRUN {
public static void main(String[] args) {
int x = 0;
int y = x;
System.out.printf("x = %d, y = %d %n", x, y);
x = 9;
System.out.printf("x = %d, y = %d", x, y);
}
}
This yields:
x = 0, y = 0
x = 9, y = 0
So I get that JAVA doesn't understand variables? Or only takes instances of variables? Is there any way to yield a true variable or you always have to update variable relationships?
I'm trying to write a transparent proxy like polipo. Polipo is written in C and I want to have the same result in java.
A simple program that can filter/monitor all connections created and closed by the browser.
To do so, I've chosen to work with sockets, because that's the only way i know to read and write raw data to and from the browser in a completely transparent way.
In this moment my code reads and writes every couple of request/response but I've noticed profiling it that the time needed to create the socket is a bottleneck.
Using URLConnection to create the same connection I need much less time than sockets.
When socket creation implies 50ms URLConnection implies only 1ms.
This is a general question about best practices for handling persisted data in JSF. My JSF page is going to have several fields that map to a managed bean. Upon a button click the fields of this bean are going to be persisted in a database. Is it better to use another bean with application scope to handle the JDBC code, or should I have a method in the bean itself to handle that? Similarly I'll need a method to retrieve the information upon a user request.
View Replies View RelatedI'm trying to understand the concurrent model of each EJB session bean types.
The singleton is well documented and seems clear to me... Only one instance and many threads using it but each method by default is synchronized because @Lock is defaulted to WRITE. We can let multiple threads use on method with @Lock(READ).
The stateless beans are in a pool I think I read somewhere that the container will ensure only one thread is using one instance at a time but this instances are recycled/reused so many threads can use the same instance but one at a time.
Is this correct ? or is it possible that multi-threading occur in one instance of SLSB ?If in the client I obtain a single reference of a SLSB and share this "instance reference" in multiple threads is it true that all the threads could use different instances on the server side ?
The stateful instance I obtain in the client is linked to one server instance and any method call will target the same instace. If many threads are using the same reference, all method calls will be synchronized and waiting for a certain amount of time that can be defined in @AccessTimeout and if the timeout is reach will end with a ConcurrentAccessException.
Can we use @Lock(READ) and let many thread use the same method like in a singleton ?
I have a primefaces editable datatable with column filtering feature.The datatable has live scrolling feature.The problem that i am facing here is that both filtering and scrolling are happening correctly with Request scoped managed bean but when the scope of the same bean is changed to view scope(javax.faces.bean.ViewScoped) then the filtering happens but on removing the keyed in key word from filter box the table content is not reset to original state and also i am not able to scroll down to next set of records on reaching the end of scrolling.Cell editing feature is working perfectly.
One thing that i observed is ,currently i am querying 5000 odd records to load into datatable.But if the number of records is limited below 5000 scrolling is happening correctly but problem with filtering remains same.I even tested by upgrading to Primefaces 5.1 from 3.Code snippet of xhtml page
<h:form id="form">
<div id="content">
<p:dataTable id="workSpaceList" var="data"
value="#{workSpaceBean.list}" widgetVar="multiSelection"
selection="#{workSpaceBean.selectedRows}" resizableColumns="true"
liveScroll="true" scrollRows="10" scrollWidth="90%"
scrollHeight="70%" styleClass="datatable"
tableStyle="table-layout:auto;width:auto important!;height:auto important!;padding-left:15px;"
scrollable="true" editable="true" editMode="cell"
filteredValue="#{workSpaceBean.filteredWorkSpaceItems}"
rowKey="#{data.lpID}" >
[code]....
I'm wondering if there's a way to build a template for managed beans which could be extended by a constructor instead of re-writing beans for each entity. I can do that quite easily for Dao objects by creating facades and using those facades to create Dao implementations for specific entities. Not sure if the same concept works for managed beans and haven't really come accross any searches.
I wrote the following but I'm not sure how to implement or even if the concept of generics and templating can be applied to managed beans in the same way it can be applied to Dao classes:
public class BeanTemplate<T> {
private ListDataModel<T> listModel;
@EJB
private GenDao dao;
private Class<T> entityClass;
[Code] .....
The above assumes there's only one method needed in the bean. I thought of extending like this:
public class EmployeeBean extends BeanTemplate<Employee> {
public EmployeeBean() {
super(Employee.class);
}
// how can the methods be called??
Is the same concept for creating dao templates possible for managed beans?
My code of start.xhtml is:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html lang="en"
xmlns="http://www.w3.org/1999/xhtml"
xmlns:h="http://xmlns.jcp.org/jsf/html"
xmlns:f="http://xmlns.jcp.org/jsf/core">
[Code] .....
when I deploy the app(glassfish) I get this message only:
hi #{user.minimum} a #{user.maximum} .
Instead of a picture: wave.med.gif and message:
hi 0 a 10 .
file hierarchy is attached
If I have the next request scoped JSF bean for example:
public class UserBean {
private String name;
private String surname;
public String saveUser(){
//service is called to save a user
}
public String updateUser(){
//service is called to update a user
[Code] ....
1.In struts for example the Action classes are singletons and I think is the way it has to be because they contain business logic and is the same logic for every user but in JSF because of you mix properties from a form and methods with business logic, these beans have to be request scoped like the above one but is very wierd that a bean which contains business logic(saveUser()....) be request scoped;I dont see it effective, is like creating a new servlet each time you want to save a user but I think is the way JSF works, right?
2 To avoid the mixing of form properties in a bean with business logic, some people say to have the form beans request scoped and actions beans session scoped.
- Is this right?
- How then can you get the request form bean in the action bean?
- The scopes in JSF are request, session and view so you cannot create singleton action beans, the best you can get is a session action bean, right?. Once again I dont see the point of creating action beans with session scoped,they should be application scoped if it existed
What are the best practices for unit testing MDBs and session beans ?How can they be tested without running an application server ?
View Replies View RelatedI've spent almost 3 hours on googling about java beans and where it is usable. What I've figured out is that a bean has a public non-arg constructor, properties and getters/setters to manipulate them. I also know that a bean contains no logic, only fields. However, I don't fully understand why I need to use beans instead of normal classes even if a class can do the same things like a bean? Are beans used to store data or what?
View Replies View RelatedI have seen in some examples like URL... a good design is to have the model and the action methods in one just single bean and the model not to be a separated class but a few properties like this:
public class CustomerBean implements Serializable{
//DI via Spring
CustomerBo customerBo;
[b]public String name;[/b]
[b]public String address;[/b]
//getter and setter methods
[code]...
Some questions:
1. If you are using hibernate or any other ORM like the above example(URL...), why not to use the hibernate pojo bean directly like it represented the form instead of using properties?:
public class CustomerBean implements Serializable{
//DI via Spring
CustomerBo customerBo;
[b]Customer customer;[/b] //represents the properties of a form
//getter and setter methods
public void setCustomerBo(CustomerBo customerBo) {
this.custom
2. Why is it said that JSF represents the purest MVC? Spring separates the model from the view too and Struts does too. I dont really understand it
I have an in-cell editable data table with a viewscoped managed bean.I found that the control never goes to the ajax event method onCellEdit when the scope of the bean is @Viewscoped but it works when the scope is changed to request scope.how to get this feature work with viewscope.Below is my code snippet
xhtml snippet
<p:dataTable id="workSpaceList" var="data"
value="#{workSpaceBean.lpInfoList}" widgetVar="multiSelection"
selection="#{workSpaceBean.selectedRows}"
scrollable="true" rowIndexVar="index" editable="true"
editMode="cell".......>
[code]....
I am working on a java bean, on a stopwatch
private String displayFormat = "%02d:%02d:%02d";// produces 00:00:00 hour:min:seconds
public void timerHasChanged() {
currentTime = System.currentTimeMillis();
// How long has been taken so far?
long secsTaken = (currentTime - startTime) / 1000;
long minsTaken = secsTaken / 60;
secsTaken %= 60;
long hoursTaken = minsTaken/60;
minsTaken %= 60;
Formatter fmt = new Formatter();
fmt.format(displayFormat, hoursTaken, minsTaken, secsTaken);
timerJbl.setText(fmt.toString());
How would i code the get and set method for format, so in property tab a user can choose if they want the timer shown in seconds, or minutes or hours or seconds&minutes
I have two images. I want to be able to click them and kick off a call to a listener in Java to change a value in the bean. I also want the view to update my dropdown (labeled "menuModel") to either be rendered or not, depending on which image I click. Alternatively, I would be fine with the dropdown simply being disabled and enabled for the same criteria.
So far, the listener kicks off fine, and the value gets updated correctly in the bean. However, the view never gets updated. I have tried this a hundred different ways, but nothing seems to work. If I hit refresh on my browser, the view updates. But I want it to do it automatically.
I am using standard JSF 2.1.
<div style="font-family: Verdana; font-size: 10pt; color: #FFFFFF">
<h2>Calibrations</h2>
<h:form id="tunerSelectionForm" style="color: #000000">
<h:commandLink>
[Code] .....
In some examples I see jsf components inside the tag view, other times dont.
- Is it important to put all jsf components inside "the view" tag?
- What would be the difference not putting them inside this tag?
Is it possible to map URL's with independent view dir structure? If so how?
My goal is to simply point an url to a specific view file:
i.e.
[URL] ....
to
not/default/path/views/main/index.xhtml
and
www.myserver.com/application/admin/
to
not/default/path/views/admin/index.xhtml
A couple solutions I found so far where:
Solution 1
PrettyFaces
I just didn't wanted to use a third party solution. This is my best solution so far.
Solution 2(a JSF solution):
navigation rule entries in the faces-config.xml file.
A bean is required, not a bad thing in above example but not great in combination with static navigation like:<h:commandButton action="index"/>
Solution 3 (another JSF solution)
Resource Library Contracts
This forces me to work in the contracts file.
None of the solutions gave me a clear solution except prettyfaces.
Are there some elegant native JSF solutions ? Something flexible and reusable? Something like a mvc controller i used to use in php applications. In this controller I was able to add a template file in the constructor and an content file in specific function. Custom paths where no problem. I didn't want to use mvc nor the php language in this project.