How to do runtime property substitution for web.xml

1. Place ${propertyName} in you web.xml file and specify the actual value via -DpropertyName=value (see a forum entry related to this...) also known as variable substitution.
   
2. If you can afford to do this at compile time then:
   
   1. do so using a build tool such as maven (an example)
      
   2. Filter the web.xml file by configuring the maven-war-plugin as shown in the last post in this thread. There are some generic examples here too but they aren't as clear cut for the web.xml file.
      

Flex 4: Best Practices for working with Events & Event Listeners

In Flex 4, it is easy to separate a component into an actionscript and mxml file, one for the logic and another for layout and skinning.

The actionscript file usually contains common framework methods such as partAdded(), partRemoved(), getCurrentSkinState() etc. whereas the skin file had all the visual components laid out.

Best Practices:

1. When adding event listeners, always put them in using the partAdded() method and NOT in the constructor.
   Because if your component is included in multiple states, then somewhere along the line while you may be switching back & forth between the states, the event listener which was added in the constructor will just disappear and it will seem like any events that you are dispatching for that listener aren't getting caught and disappearing into limbo.
   A guess here is that even though the listener may not have had a weak reference, taking the component on & off the stage between state changes might cause its listener to get garbage collected.
   With the use of partAdded() method to add the event listener, this risk disappears because even if the same component is being taken off the stage and being put back then the framework will make sure to call partAdded() again. Unlike the constructor which had already been used to create the object.
   

Flex Deep Linking and Server Side Redirects

With Flex its easy to:
a) use deep-linking (IBrowserManager & BrowserManager) to create application URLs that allow the use of the browser's backward & forward navigation buttons,
b) bookmarking a deep-linked URL and reloading it also works just fine

B U T ... what doesn't work is when you need to authenticate users before letting them access their bookmarked content. The reason behind this is simple ... the out-of-the-box javascript (history.js file) provided by the flex framework uses the # (pound/sharp) symbol to manage the deep link fragments. For ex:

1) http://www.hostname.com/application.swf#view=account
2) http://www.hostname.com/application.swf#view=profile
3) http://www.hostname.com/application.swf#edit=account
4) http://www.hostname.com/application.swf#edit=profile

Now according to the HTTP spec, the part after the # symbol is not sent over to the server in the HTTP request. This means that your server has no clue where to redirect the users after they successfully authenticate!

What can you do?

Workaround # 1:
1) Provide a bookmark button in the application itself and replace the # symbol with the ? symbol when storing the link.
2) Edit your client side to treat the ? symbol in the same way it treats the # symbol, therefore picking up the deep link fragments properly.

Workaround # 2:
1) Have your users manually edit their bookmarked links to replace the # symbol with the ? symbol.
2) Now that the deep link fragment is making it over to your server side as a URL parameter, edit your server side to replace the ? symbol with the # symbol when redirecting the user back to their bookmarked link. If you are using the spring-security framework then you can refer to the following blog as a reference on how to configure your application context's xml files properly.