Lesson 7: Pass a parameter to another page

The file allcustomers.jsp lists every row in the database. In the next exercise, you will create a second page that displays the details from one row in the database. In this exercise, you will add a link on the file allcustomers.jsp that sends the user to the detail page. That link also indicates which record to display on the detail page.

Add the link to allcustomers.jsp

About this task

Show Me

Procedure

  1. Open the allcustomers.jsp file
  2. In the Palette view, click the Enhanced Faces Components drawer to open it.
  3. From the Enhanced Faces Components drawer, click the Link control to select it, not the Link - Request control.
  4. With the Link control selected in the Palette view, click directly on the {LASTNAME} text control.
    Do not drag the Link control onto the JSP. The Configure URL window opens.
  5. In the URL field of the Configure URL window, type the following file name exactly as shown: 
    updatecustomer.faces

    This is the name of the page you will create in the next lesson to show only one row in the database, but with a faces extension instead of a jsp extension. The faces extension tells EGL that the file is to be treated as a JavaServer Faces file.

    Leave the Label field blank. Without a label specified here, the link will use the text of the last name field itself as the text for the link.

  6. Click OK.

    If you see a link next to the {lastName} control named Link label, you did not place the link directly onto the {lastName} control. Click Edit > Undo and try again. When the link is placed correctly, you see a chain link icon next to the {LASTNAME} text control.

  7. Save the page.

Results

The page looks like this:
Current appearance of the page for allcustomers.jsp

Add the parameter to the link

About this task

Next, you must specify which record will be displayed on the updatecustomer.jsp page. To send this information to that page, you specify an HTTP request parameter for the link you just added. HTTP request parameters are name-value pairs of plain text that are sent over the Internet by way of the HTTP protocol. Request parameters are an efficient way to send and receive simple data between programs within an application.

Procedure

  1. Click directly on the link icon of the link control you just added to the {LASTNAME} control.

    The link icon itself, , not the text control, must be selected before you can continue. You have the link selected correctly if it is lightly shaded and the selection box is surrounding the link icon and the text control. Do not double click the link icon.

  2. Without moving the selection away from the link icon, open the Properties view.

    The Properties view is usually at the bottom of the workbench. If you can't find the Properties view, click Window > Show View > Properties.

  3. In the Properties view, click the Parameter tab, directly below the hx:outputLinkEx tab.

    If you can't find the Parameter tab, be sure you have clicked directly on the icon to select it.

  4. Click Add Parameter.
    A new parameter named Name0 is added to the list of parameters.
  5. Click the cell holding Name0 and replace the name with the following text as the new name of the parameter: 
    CID
  6. Click the cell holding Value0 to highlight it.
  7. Click the Select Page Data Object button.
    The Select Page Data Object window opens.
  8. Under Data Objects, expand Data.
  9. Expand customers - Customer[].
  10. Click CUSTOMERID - CUSTOMERID.
    The Select Page Data Object window looks like this:
    Select page data object window
  11. Click OK.
  12. Save and close the page.

Results

Now, the value of the CID parameter for the link is bound to the value of the customer_id field. When the user clicks the link, the runtime code invokes the file updatecustomer.jsp and makes the customer ID number available to the onPreRender function of the related JSF handler.

In the next lesson, you will create the web page for the file updatecustomer.jsp, and later, you will set up the JSF handler to receive the parameter and to show only the customer with that ID number.