MyFaces Features

Saving the full tree and model state information in the client response

Traditional JSP Applications save their state information within HttpSession objects. This is an easy to use but poor approach:

HttpSession objects must have an expiration date (timeout) that prevents the server from running out of memory over the time. The always boring question for web admins: How long should I set the session timout?
Server restarting is a thrilling task: Will all objects in active sessions be restored successfully? If implementation classes have changed this task is likely to fail.
Running multiple redundant servers is a challenge. You must use cluster environments which are expensive and difficult to handle.

MyFaces has a different approach. It makes it possible to write sophisticated applications without any use of the HttpSession. All state information of the jsf tree and (optionally the model beans) is encoded to the client response in the form of query parameters and hidden inputs in forms.

Support for saving model state

MyFaces introduces a new Component "UISaveState" with the corresponding Tag "<myfaces_ext:save_state>".
Example (see "sample1.jsp"):

    ...
    <jsp:useBean id="calcForm"
                 class="net.sourceforge.myfaces.example.model.CalcForm"
                 scope="request" />
    ...
    <f:use_faces>
        ...
        <x:save_state id="save1" modelReference="calcForm.number1" />
        <x:save_state id="save2" modelReference="calcForm.number2" />
        <x:save_state id="save3" modelReference="calcForm.result" />
        ...

The current values of the three properties number1, number2 and result get automatically saved within the client response and restored from the following client request.

You can also save the whole bean.
Example:


    ...
    <jsp:useBean id="calcForm"
                 class="net.sourceforge.myfaces.example.model.CalcForm"
                 scope="request" />
    ...
    <f:use_faces>
        ...
        <x:save_state id="save1" modelReference="calcForm" />
        ...

The whole bean automatically is saved (serialized) and restored by MyFaces.

Keep in mind that to be able to save and restore the value of a bean property or the bean itself, it must either be serializable or have a type that is supported by a Converter (see package myfaces/converter/map).

State Saving Methods

MyFaces supports two ways of saving client state information:

"On the fly"
State info is encoded within HREFs and FORMs at once.
Drawback: The state of dynamic request time attributes that are calculated during JSP processing will not be saved correctly. Also the state of dynamically added or removed UIComponents will not be saved correctly.
"Tokens"
State info is encoded within HREFs and FORMs as tokens (placeholders) that are replaced by the real state info after the JSP processing of MyFaces tags has finished.
Drawback: The usefaces tag must buffer all produced HTML code within it's body (see javax.servlet.jsp.tagext.BodyContent) and must do a search'n'replace before writing the content out to the response stream.

MyFaces supports two methods of encoding the state information:

"Normal"
All state values are encoded as normal URL parameters.
i.e. Query parameters in HREFs and hidden inputs in FORMs
"Zipped"
All state values are encoded to a String of key/value pairs that is zipped (GZIP) and encoded to allowed characters (Base64). This String is then written as one query parameter or hidden form input.

UINavigation

A simple navigation component to build a vertical menu structure.
(see web\example\inc\navigation.jsp for an example)

UIMessageList

A very simple component that prints all messages in a <ul> list.
(see web\example\sample1.jsp for an example)