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

Inside Gradebook - June 9, 2005

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

Inside Gradebook - June 9, 2005

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

Inside Gradebook - June 9, 2005

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

Inside Gradebook - June 9, 2005

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

Inside Gradebook - June 9, 2005

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

Inside Gradebook - June 9, 2005

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

Inside Gradebook - June 9, 2005

Managed Change• Living specs• Spec team updates

CVS• Discussion via

BaseCamp & Confluence

Inside Gradebook - June 9, 2005

Integration – Tool / Component

App Presentation External Apps

App Business Logic

Inside Gradebook - June 9, 2005

Integration – Application / Service

App Presentation External Apps

App Interface

Shared Model Logic

Service Interface

Inside Gradebook - June 9, 2005

Integration – Direct Client

GradebookSakai 2APIs

Inside Gradebook - June 9, 2005

Integration – Facades

GradebookGB

Facades

Sakai 1.5APIs

Sakai 2APIs

Tests

Standalone

Inside Gradebook - June 9, 2005

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.

Inside Gradebook - June 9, 2005

JSF 1.1 - Berkeley Pilot Experience

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

Inside Gradebook - June 9, 2005

Taming JSF – Bugginess• Switch to MyFaces

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

Inside Gradebook - June 9, 2005

Pure Request Scope

R

AppContext

DB

R

AppContext

R

AppContext

R

AppContext

Inside Gradebook - June 9, 2005

Session Scope

R

AppContext

DB

R R

Inside Gradebook - June 9, 2005

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

R

AppContext

DB

R R

AppContext

AppContext

Inside Gradebook - June 9, 2005

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

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

Inside Gradebook - June 9, 2005

JSF - Data Synchronization• Phase-aware backing beans

– PhaseAware interface– InitializableBean superclass

• Controlled guaranteed initialization from DB

Inside Gradebook - June 9, 2005

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

Inside Gradebook - June 9, 2005

JSF - Incremental GeneralizationJSP 2

1. Embedded2. Included3. JSP tag4. Java tag

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

Inside Gradebook - June 9, 2005

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" >

Inside Gradebook - June 9, 2005

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

Inside Gradebook - June 9, 2005

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

Inside Gradebook - June 9, 2005

Results• Delivered specified functionality on

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

Inside Gradebook - June 9, 2005

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