Remember the DD tags with SRRN:
<web-app>
<security-role>
<role-name>member</role-name>
</security-role>
…
Security Roles Require Names
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Category Archives: SCWCD tips
Commodore64 – BASIC – Base64
Not much to say here.
Of the 4 autehntication types, “BASIC” uses Base64, in the same way that on a Commodore 64 you’d write BASIC.
Showing my age there.
Listeners and Events
There are 8 Listeners to remember. We know there are attributes in 4 scopes because we know how to Pick the Right Scope Automatically, but you can’t listen to Page attributes, it doesn’t make sense, so that leaves us with RSA; Request, Session and Application. These tally with the objects:
- ServletRequest
- HttpSession
- ServletContext
There is a Listener for each of these objects for lifecycle events, and for attribute events, so that gives us 6 of the Listener Interfaces:
- ServletRequest[Attribute]Listener
- HttpSession[Attribute]Listener
- ServletContext[Attribute]Listener
HttpSession gets the 2 extra interfaces:
- HttpSessionBindingListener – Attribute objects implement this if they themselves want to know whenthey are [un]bound
- HttpSessionActivationListener – Listen here to have a nose when the session is gallivanting around
Events
There are just 6 events, one for each lifecycle event:
- ServletRequestEvent
- HttpSessionEvent
- ServletContextEvent
and one for each attribute-related event:
- ServletRequestAttributeEvent
- HttpSessionBindingEvent – (It’s easy to remember this black sheep because its initials rhyme with the worlds local bank HSBE)
- ServletContextAttributeEvent
11 EL Implicit Variables
All the EL implicit variables are Maps except for pageContext.
To remember the attribute-holding scope objects, just remember to Pick the Right Scope Automatically and stick the word “Scope” on the end:
- pageScope
- requestScope
- sessionScope
- applicationScope
Then you have 4 param and header objects of the form : (param|header)[Values]
- param
- paramValues
- header
- headerValues
Then I just remember the last 3:
- cookie
- initParam
- pageContext (not a Map, it’s the JavaBean)
Captain Pan PreVents Captain Hook
This is (a rubbish one) just to help me remember the DD tags:
<context-param>
<param-name>n</param-name>
<param-value>v</param-value>
</context-param>
Whereas Servlet params are “in-it”:
<servlet>
<init-param>
<param-name>n</param-name>
<param-value>v</param-value>
</init-param>
…
</servlet
Direct a Film about Petal Ink
I’ve made a timelapse film of some daffodils blossoming but I really should do another one of a rose with its stem split into two different bottles of ink.
Not a very interesting post, it’s just another think I need top remember from this book for my exam. 
Direct a film about PeTaL INk
Boils down to:
Jsp Directives are Page, Taglib and Include
Tie up the JSP implicit variables with SCRAPROPE
Use the acronym SCRAPROPE to remember the JSP implicit variables:
session
config
request
application
pageContext
response
out
page
exception
I should really credit Russ for coming up with the acronym. I think my attempts, SCORP RAPE and SPORE CRAP, weren’t as catchy.
Pick the Right Scope Automatically
As I previously metioned, I’m taking the SCWCD exam tomorrow. When trying to cram for any exam I like to make up short poems, acronyms or just random chains of though. For example, I know the difference between Mitosis and Meiosis because Meiosis begins with “Meow” which is what cats do and they have four legs… anyway…
My first thing to remember is that a JspContext has a findAttribute method that I can use to Pick the Right Scope Automatically.
The acroynym, PRSA, is the order scopes are searched for attributes: Page, Request, Session, Application. You know that the S stands for Session because you can’t put attributes in a servlet. This also allows you to remember which objects can have attributes.