1 Reply Latest reply on May 4, 2011 12:55 AM by gebuh

parameters and variables

nobody4601 May 3, 2011 12:58 PM

Hello, I'm new to seam and actually in web development at all, so there are probably many things I do not understand, or I think I understand, but I'm wrong :)

The thinks I need should be relatively simple:

1) take a parameter discountId from an URL:
http://127.0.0.1:8080/seam-booking/home.seam?discountId=33
and send it to the session bean's method to get the object with corresponding ID.
So I have:

@Stateful
@Name("DiscountController")
@Scope(SESSION)
@TransactionAttribute(REQUIRES_NEW)
public class DiscountControllerAction implements DiscountController {
  
  @PersistenceContext
  private EntityManager em;
  
  @RequestParameter
  String discountId;

  public Discount getDiscountById() {
    String sQuery = "Select dsc from Discount dsc WHERE dsc.id = ?1";
    Query query = em.createQuery(sQuery);
    Long dscId = Long.decode(discountId);
    query.setParameter(1, dscId);
    return (Discount) query.getSingleResult();
  }

and in home.xhtml:

<h:outputText id="outText1" value="#{DiscountController.getDiscountById().formatedText}" escape="false"/>

This was the only way I could make it work but I'd prefer to store that discountId url parametr in some variable "variable" and then use something like:

<h:outputText id="outText1" value="#{DiscountController.getDiscountById(variable).formatedText}" escape="false"/>

such "variable" I could also use later, but I do not know how to do that and if it is possible at all.

Actually, that's related to my second question:

2) I need to display more properties from the "Discount" what is the return type from the

#{DiscountController.getDiscountById()}

So shoud I each time use

<h:outputText id="outText1" value="#{DiscountController.getDiscountById().formatedText}" escape="false"/>
<h:outputText id="outText2" value="#{DiscountController.getDiscountById().name}"/>
<h:outputText id="outText2" value="#{DiscountController.getDiscountById().address}"/>

or is there a way to create variable "discount" and use

<h:outputText id="outText1" value="#{discount.formatedText}" escape="false"/>
<h:outputText id="outText2" value="#{discount.name}"/>
<h:outputText id="outText2" value="#{discount.address}"/>

thanks a lot!

Peter

1. Re: parameters and variables

gebuh May 4, 2011 12:55 AM (in response to nobody4601)

That ?discountId=33 is a requestParam you can access from your page.xml. If you take a look at it you should see something like:

<param name="discountId" value="#{DiscountController.discountId}"/>

this calls the setter for discountId
To use this in a query I would use an entityQuery or you could generate a query on the fly, but I would hesitate putting it in a getter.
Maybe you could use an @Observer in conjunction with raise event to update the discount along with @Factory. So something like:

@Stateful
@Name("DiscountController")
@Scope(SESSION)
@TransactionAttribute(REQUIRES_NEW)
public class DiscountControllerAction implements DiscountController {
  
  @PersistenceContext
  private EntityManager em;
  
  @RequestParameter
  String discountId;

  private Discount discount;

  @Observer("setDiscountId")
  @Factory(value="discount")
  public Discount findDiscountById() {
    String sQuery = "Select dsc from Discount dsc WHERE dsc.id = ?1";
    Query query = em.createQuery(sQuery);
    Long dscId = Long.decode(discountId);
    query.setParameter(1, dscId);
    return (Discount) query.getSingleResult();
  }

public Discount getDiscount(){
     return this.discount;
}

public void setDiscount(Discount discount){
     this.discount = discount;
}
public String getDiscountId(){
     return this.discountId;
}

public String setDiscountId(String discountId){
     this.discountId = discountId;
     Events.instance().raiseEvent("setDiscountId");
}

and in xhtml:

<h:outputText id="outText1" value="#{discount.formatedText}" escape="false"/>
<h:outputText id="outText2" value="#{discount.name}"/>
<h:outputText id="outText2" value="#{discount.address}"/>

I'm not sure where you want to set the discountId but if you did something like:

<h:inputText id="in1" value="#{DiscountController.discountId}" />

maybe with some reRendering tags to change the values of your output.
I'm unsure how this works with stateful beans, I use this with stateless pojo's, so I could be completely off base. Output could be different, I know how to set a var for a resultList that would be used in a dataTable, but I'm unsure about using singleResult.
HTH