I have a simple page with a form that includes a TextField. I have set the model object (Serializable POJO) with a single variable called containerId. No matter if I use a LoadableDetachableModel or the standard Model.of(), if I have a PageParameter also named containerId then the form model behavior breaks causing the value to always remain as what the PageParameter value is set. If I change the page parameter name to container and pass that value into my model on initialization the problem goes away. Has anyone else experienced this? If you can provide any details as to why this is happening?
It sounds like the conflict is in the URL that is produced when you submit the form. I would speculate that your page is mounted in such a way that the PageParameters are encoded as query parameters in the URL, and that the form is submitted via a GET which therefore encodes its values as query parameters in the URL. Thus two query parameters with the same name get added, and one of them is lost.
So, there are at least two options you can try:
Change the form to POST (add method="POST" to the HTML)
Mount the page in a way that encodes the page parameters differently, for example with something like the following:
mountPage("/page/${containerId}", YourPageClass.class);
Related
I have a struts action flow(struts-1.x framework), which, when executes, the action class ActionFlowActionUnit1.java sets a String variable varName to request using the code
request.setAttribute("varNameFromRequest", varName);
and the flow finally leads to the loading of a jsp Page1.jsp.
Now, Page1.jsp contains a button, which, when clicked, initiates a new struts action flow, which has the action class ActionFlowActionUnit2.java. In this class, I want to use the varName which I had set in request using request.getAttribute().
How can I do it WITHOUT USING SESSION?
Technically, I'm not sure if achieving this using requestis possible, because, triggering a new struts-action will lose all other information in the request that was previously set (if I'm correct).
I couldn't get anything from Google.
As you say, it is not feasible technically as you want it (every http request from the browser creates a new HttpServletRequest object)
You have 2 options:
Using the Session, which you want to avoid as far as I understand
Bring back and forth some parameter into every successive request with the value you would like to keep.
The second option would mean to store some parameter inside your Page1.jsp <form> with the variable you need your second action to receive, and then rinse and repeat. This is a pure html form solution.
If you are implementing a complex flow, this looks a fair case to have a look at Spring Webflow. There you can manage flow-level variables, which are stored at a "different" scope than request or session, and looks exactly what you want.
http://projects.spring.io/spring-webflow/
Is there a way to call ids that are created in html page without specifically giving wicket:id in the component. If so, how can I do that?
What I am trying to accomplish is to get access of the component to assign a default value from CMS. I could assign the default value using JS, however I need that value to be populated to Java so that I could use that in my class to update my business logic depending on the defaulted value.
As I understand it, Wicket is component oriented which means that single component (piece of HTML code) can't see all the HTML. And my guess is that at some late stage, you want to look at the whole page HTML and do something with a DOM node with a specific ID.
I'm not sure what the correct solution should be. One way is to put the value into the user's session, so it's available for each component and your business logic.
Working on a large Web app, I have houndresds of JSPs.
Each JSP includes (ONLY) a set of internal tags, for instance:
<AAA:INPUT value="bbb" state="<%=getPageState()"/>
This tag is rendered into an HTML input field, with a readonly/enabled state, based on the return value from getPageState().
This basically allows me to set the complete page as enabled/disabled from a single entry point.
I don't like this (mainly because it drives me away from writing the HTML I want and I need to maintain attributes for each HTML attribute I want), I know I can something similar on client side with JavaScript.
Are there other approachs to control the state of a complete JSP form in a single point on the web-server side?
The way I would go about this would be to convert the getPageState() method into a tag, and then use this tag within your custom tags. That way, you don't need to explicitly pass in the page-state on every invocation of your custom tag.
Of course, this means that you would have to modify all your custom tags to use this new tag, but I think that's better than having your code littered with explicit calls to get the page state. Not to mention, an opening for inconsistencies if a developer forgot to check the page state.
Also, now the decision as to how the element needs to be rendered rests in the custom tag itself (where it belongs).
The only problem I see is that now you have to make multiple (redundant) calls per element to get the page state, which is not that efficient. To get around this problem, you can have your custom tag (that gets the page state) set a page attribute, and have your custom tags inspect this page attribute to decide if the form element should be disabled or not (another way would be to create a variable with the scope AT_END).
In many cases you want to add HTML-Controls or Facelets to your Website, but how easy is it really to just access these when you call upon an action?
I have the following commandLink to execute an Action
<h:commandLink action="#{MyBean.save}" value="">
<f:verbatim><input type="button" value="Save"/></f:verbatim>
<f:param name="id" value="#{MyBean.id}"/>
</h:commandLink>
The Param is there to save the QueryString-state so my application won't crash.
Now, imagine you have a <input type="text" /> or <h:inputText value="hello" /> now these components are fundamental to get your site up and running, especially if you are creating some dynamics.
However, if the Controls are not Bound to anything, or if you have a Listbox which you can add elements to with JavaScript, how do you access these when you execute the commandLink or commandButton? Do you Have to bind the controls to your Bean or is it possible to access this FaceContext in another way to retreive the values of either a listbox, input text or whatever else you would want to have?
It can be difficult to treat a JSF-rendered page as a big glob of HTML and JavaScript (which, I think, is at the heart of the question). You cannot add arbitrary form controls to the application on the client and expect the JSF framework to interpret them. JSF uses pre-defined components, so a component would have to know how to interpret the extra data coming from the request. Because it all ends up as a HTML form interpreted by a servlet, the data sent from the client will still end up in the parameter map - but, these values won't pass through the JSF lifecycle, so won't benefit from validation/data binding/etc.
A JSF control tree looks much like any other widget tree (like Swing or SWT):
UIViewRoot
|_HtmlForm
|_HtmlInputText
|_HtmlCommandButton
A JSF control basically works like this:
a UIComponent instance encapsulates the values (initially populated from the JSP/Facelet); example: HtmlInputTextarea
When the page is rendered, the lifecycle looks up the Renderer implementation for the component; the Renderer writes markup to the output
When the form is posted, the same renderer looks at the incoming parameter map for keyed values it recognises and will eventually (after conversion and validation) push the new value into the UIComponent (which may in turn push it to a value binding for the model)
Taking your specific example of a listbox - this is a tricky one. JSF provides a HtmlSelectManyListbox which ends up as a SELECT element in HTML. It is possible to add OPTION children to the DOM using JavaScript on the client, but this doesn't do any good when it comes to submitting the form. If you read the HTML spec, it says:
Only selected options will be successful. When no options are selected, the control is not successful and neither the name nor any values are submitted to the server when the form is submitted.
So, when the form is submitted, only the list elements that are selected by the user would be transmitted to the server. You would need some hidden fields to get all the new data to the server. There isn't a control in the core set that will help you with this.
You have a few options:
Find an existing control from a 3rd party library that does this. If you can't find one, consider using AJAX to perform the updates - look at the RichFaces select controls for inspiration.
Write your own control (warning: read the spec and be aware of the many fiddly, manual steps)
Put up with having to perform a POST operation every time you want to add an element to the list
You can retrieve values from "non-JSF" controls on your page using the standard request parameter map that can be accessed with
FacesContext.getCurrentInstance().getExternalContext().getRequestParameterMap()
in whatever action you call eg. MyBean.save()
So I have a table in a jsp page with several rows and checkboxes for each row. I created a js function that creates an array of the value on the checkboxes. I want to send this array over in an ajax call so I toJson-ed it but I dont understand how actionbean variables get set with these parameters. Can anyone help? THANKS!
Good question. Typically you create instance variables on your action beans, expose w/ getter/setters, and they are populated automagically via form post params or get params.
If you had a small handful of checkboxes, you could make a boolean for each one on your ActionBean, then your ajax call could be to a URL like "Preferences.action?box1=true&box2=false&box3=false".
If you had a ton, you could create a List on the ActionBean. I've only dealt w/ this the non-ajax way, but you'd set the name attribute on the checkbox to something like this: name="preferences[0]". I think you could do a jquery ajax call this way too, but you might have to url encode the name of the param.
I think you could also look into the jquery form plugin to simply POST the json over.