here we collect ideas for btw.

this site contains:

this site doesn't include:

the result can be used for:

new apis

FacesContext#getWindowId independent of other apis, new artifacts,... we should provide this method to expose the current window-id easily.

new components

new attributes for existing components

command components should get the following new attribute(s) to control the window-id (e.g. to open a popup with a different window-id). this information has to be sent as request parameter (javax.faces.windowId), because the information needs to be available before restoring the view.

if no information is provided via javax.faces.windowId, the windowId parameter of the url will be used (if it exists, otherwise a new window-id will be created). we need "none" e.g. for old command components which don't have this attribute. in this case we might need a fallback (depending on what we want to support).

implicit variables

storing the window-id

the usual strategy is to store the window-id in the url due to the different browser restrictions. we could also do it via state-saving but there are also cases which would break the whole mechanism (e.g. a page refresh or pressing enter in the address-space). some of those cases already break the view-scope.

the only problems with the window-id in the url are:

  1. pretty urls
  2. opening an url in a new window.

possible solutions:

known limitations:


in codi we have automatedEntryPoint to allow that external apps can query pages without creating new windows.

DRAFT: Discussion ....

Known solutions for storing the window-id on the client-side (which doesn't support all use-cases on the client-side):

  1. Hidden field
    • No support for GET requests and manual page refreshes
  2. Cookie only
    • Doesn't work at all
  3. URL only
    • Clones a window with "open in new tab" and similar
  4. URL + js for detecting new windows (see

  5. URL (window-id) + Cookie (request-id) which gets set via js directly before the request + reset of the Cookie asap
    • Also supports GET requests -- possible problem (depending on the browser): parallel windows which set the cookies in parallel; additional mouse buttons e.g. binding of the middle mouse button)
  6. URL + request-id in a hidden field for POST requests and
    • the logic of javascript:document.location = this.href + ' & amp ; ' + /*stores the request-id*/; return false; as autom. chained code for GET requests

  7. sessionStorage of HTML5
    • Looks promising with Firefox but not with other browsers
  8. Client-side window-handler of CODI
    • A completely working solution with the drawbacks of page-flickering and the incompatibility with libs like PrettyFaces.

Mixed approach of the first prototype

detect if it's a valid request before the FacesContext gets created. a valid request is a request with a window-id AND a request-id (the request id is linked to a window-id and not valid with other window-ids) the request-id is stored in a hidden field and gets transferred to a cookie before a request -> it isn't in the url and it isn't shared between tabs.

first request:

second request:

ajax requests have to update the hidden field with the request-id in >any< case.

open a new tab and enter the url or open a bookmark -> it's the same like the first request scenario -> done

click "open in new tab" via something else than left mouse-button without other keys and keys like the enter key -> remove the cookie (needs to be tested with all browsers) -> new tab gets opened with window-id (from the url) but the cookie was removed -> invalid request -> new window gets created

if all that works, the only constellations which don't work are:


Further readings

Other Frameworks

Frameworks like Stripes has a Flash Scope that support multiple windows using a query param.

Common use cases

1. Use target="_blank"

<form action="/faces/file.xhtml" method="POST" target="_blank"> 

2. Use :

<form action="/faces/file.xhtml" method="POST" target="foo" onsubmit="'', 'foo', 'width=450,height=300,status=yes,resizable=yes,scrollbars=yes')"> 

Drafts/WindowId (last edited 2011-09-01 04:14:09 by GerhardPetracek)