Tuesday Jan 24, 2006

Another Page Fragment Tip and a Question About Perferred Tutorial Formats

In our last blog, Gail showed you how to access page fragment properties. Sometimes, you might want a page fragment to determine what page it is being shown in. To do that, you ask the current view for the view identifier, like this:

String viewId = getFacesContext().getViewRoot().getViewId();

This returns something like "/Page1.jsp" or "/foo/Bar.jsp", and can be used to choose conditional logic based on what page you are in.

For a simple test, add a staticText component to the page fragment, and put the following in the page fragment's init method (which gets called after the prerender() method of the page that contains the page fragment).

 staticText1.setText(getFacesContext().getViewRoot().getViewId());

We have a question for you. Currently our tutorials are in HTML format. However, we have had several customer requests for the tutorials to be in PDF format. If you prefer that the tutorials are in PDF, please send us an email at CreatorDocsFeedback@Sun.Com. If we receive a sizable number of requests for PDF, then we will consider delivering future tutorial releases in both HTML and PDF.

Friday Jan 20, 2006

Aloha, Discovering via Code Completion, and a Page Fragment Tip

Chris: I love the Internet. Not only does it let me work with teams all over the world, such as when I worked with the NetBeans team in Prague, the Internet also enables me to work from anywhere. Today I am on the Big Island in Hawaii. It is a relief getting away from the constant rain and flooding in northern California. On the west side of the Big Island we have the opposite problem -- a severe drought.

I want to talk a bit about discovering how to use Creator's editing features to figure out how to solve your programming tasks on the fly. For example, someone asked in the EA forum how to figure out what column a component is in. I wasn't sure whether the person was asking about a Table component column or a database column so I answered both questions. I didn't really know the answer, so I opened the Java editor on a page that had a Table component, which was bound to a database table. To figure out how to get the Table Column that a component is in, I typed "hyperlink1.get" (where hyperlink1 is the id of a hyperlink component in a table column in my Table component) and pressed Ctrl+Space to raise the code completion box. In the list that appeared was getParent(). This seemed a likely candidate, so I chose that one. I typed ".get" and pressed Ctrl+Space again. In the list was getId(), and I chose that one.

I used the same process to discover how to get the database column associated with a component: hyperlink1.getValueBinding("text").getExpressionString().

It is kind of a bassackwards methodology, but sometimes I find the code completion method to be quicker than reading the Javadoc. If I want to learn more about a method that I have discovered using code completion, then I can look in the little Javadoc pop-up that appears above the code completion box, and I can open the various API references that are available from the Dynamic Help window. If you want to learn more, see the Using the Java Editor tutorial at http://developers.sun.com/prodtech/javatools/jscreator/ea/jsc2/learning /tutorials/javaeditor.html. My other friends for discovering and exploring are the Message Group component (where I use info(string) to send diagnostic messages at rendering time), and the server log (where I use log(string) to send lifecycle and event handling messages to the log).

Gail: This week a customer asked if he could use templates in Creator to create pages with the same header, footer and side menu. Page fragments are the perfect solution for this and the Page Fragment Box component is documented in our tutorial Using Page Fragments at http://developers.sun.com/prodtech/javatools/jscreator/ea/jsc2/learning/tutorials/pagefragments.html.

An updated version of this tutorial is coming out Wednesday, 1/25. The tutorial includes a page fragment that holds links for navigating between the pages in the application. While writing this tutorial, I discovered how to disable the link on the current page. Here are the instructions:

1. Create a new project.

2. Put a page fragment on the page (Page1). Name the page fragment Navigation.

3. Add a Hyperlink component to the page fragment. Set the hyperlink's id property to homeLink, text property to Home, and the url property to /faces/Page1.jsp.

4. Open the Java source code for Page1.

5. Add the following code to the prerender method:

public void prerender() { 
    Navigation navigationFragmentBean = (    
      Navigation)getBean("Navigation");
    Hyperlink homeLink = navigationFragmentBean.getHomeLink();
    homeLink.setDisabled(true);
 }

6. Right-click in the Java Editor and choose Fix Imports.

7. Run the application and verify that the link is disabled.

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