inside gradebook - june 9, 2005 inside gradebook or: how i learned to (almost) stop worrying &...

Inside Gradebook - June 9, 2005

Inside Gradebook

Or: How I Learned to (almost) Stop Worrying & (almost) Love JSF 1.1

Ray Davis – UC Berkeley


Pragmatic Development• Incremental• Cyclical• User-driven• Lazy optimization• Lazy generalization


Small Interdisciplinary Team• Functional specification

– Ben Brophy - UI - MIT– Oliver Heyer - Project Manager - UC Berkeley

• Implementation– Ray Davis – UCB– Josh Holtzman - UCB

• Sakai integration– VARIED

• Samigo integration– VARIED


Goals• Best-of-breed online gradebook• Meet MIT and UC needs• Built on new Sakai framework• Built on new Sakai course management API• Built with rich JSF component set• Close integration with Samigo• ... Due in four months


Goals, 2• DUE BEFORE new Sakai framework• DUE BEFORE new Sakai course

management API• DUE BEFORE rich JSF component set• DUE BEFORE Samigo completely stable


Something's Gotta Give• Delivery date?• Functionality?• Stability?


Jettisoned• Close cross-dependencies• Anything not in Sakai 1.5 (e.g., sections)• Two-way sharing with Samigo• Complex UI; potential design issues

– Percentage-weighting– Categories– Histories– Graphs

• Immediate use by MIT or UC Berkeley


Managed Change• Living specs• Spec team updates

CVS• Discussion via

BaseCamp & Confluence


Integration – Tool / Component

App Presentation External Apps

App Business Logic


Integration – Application / Service

App Presentation External Apps

App Interface

Shared Model Logic

Service Interface


Integration – Direct Client

GradebookSakai 2APIs


Integration – Facades

GradebookGB

Facades

Sakai 1.5APIs

Sakai 2APIs

Tests

Standalone


The Scary Part - JSF• JSF 1.1 lacks components.• JSF 1.1 has more general problems.• JSF 1.2 is likely to fix many.• JSF 1.2 isn’t available.


JSF 1.1 - Berkeley Pilot Experience

• Buggy• Unpredicted results• Tangled backing beans• Forced session scope


Taming JSF – Bugginess• Switch to MyFaces

– Still buggy, but…– Releases more often– Access to CVS head


Pure Request Scope

R

AppContext

DB

R

AppContext

R

AppContext

R

AppContext


Session Scope

R

AppContext

DB

R R


Request Thread ScopeAKA task scope, page flow scope, workflow scope....

R

AppContext

DB

R R

AppContext

AppContext


Request Threads in JSF 1.1• Carry thread state in UI component• New FlowState component, inspired by

MyFaces SaveState<gbx:flowState bean="#{phaseAwareBean}" />


JSF - Data Synchronization• Phase-aware backing beans

– PhaseAware interface– InitializableBean superclass

• Controlled guaranteed initialization from DB


Taming JSF - Coding Conventions

• One page = One backing bean• Backing bean is selectively Serializable• Confine DB queries to init()• Avoid unnecessary DB queries• No domain objects in request thread state• HINT: Use PhaseListener when debugging


JSF - Incremental GeneralizationJSP 2

1. Embedded2. Included3. JSP tag4. Java tag

JSF 1.11. Embedded2. --3. --4. Java component


JSF - Incremental Generalization• Solution: MyFaces aliasBeanFrom addAssignment.jsp :

<x:aliasBean alias="#{bean}" value="#{addAssignmentBean}"> <%@include file="/inc/assignmentEditing.jspf"%></x:aliasBean>

From editAssignment.jsp :<x:aliasBean alias="#{bean}" value="#{editAssignmentBean}"> <%@include file="/inc/assignmentEditing.jspf"%></x:aliasBean>

From inc/assignmentEditing.jspf :<h:inputText id="title" value="#{bean.title}“

required="true" >


JSF - Components• Reduced need• Mocked up with embedded• Move over to Sakai 2 as available• Pager tag - Thanks, Jon Andersen!


Bumps• Changes in responsible parties• Changes to facades• Changes to service interface• Changes to formatting• Reorganization & repackaging of files• Changes to Sakai framework expectations


Results• Delivered specified functionality on

schedule• Multiple DBs• Multiple deployment styles• Back button, multiple windows/tabs• Less server load• Foundation for future work


Future Work• Refactor tests• Domain objects in request threads• JSF - redirecting URLs• JSF - out of sync URLs• JSF - precompile JSPs• Submit MyFaces approach to wider group• Restore MIT/Berkeley functionality

inside gradebook - june 9, 2005 inside gradebook or: how i learned to (almost) stop worrying &...

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