Implementation Changes

I've hit some snags during implementation. I've made some design changes to accommodate them. I'm going to document them as I go to keep Ken informed, and to have a place to go back to in case I ever wonder "WTF did I do that?"

Removed Owner, Group and Permissions

I removed file ownership and access control for two reasons. They would either require some ThreadContext object to track the actor, or adding a "actor" parameter to every method call to check permissions. This would pollute the interface right now. It may be added later.

Java has a nice ACL library that we may want to use instead. My mental stack is too full to figure it out right now.

Address is a first class citizen

I promoted the "Address" abstraction to be a first class citizen. It's used by Contact, Meeting, and Photo, so I think it should be 1st class. I am making it immutable for now.

Created our own MimeType

I was planning to use the activation framework's MimeType object, but it isn't immutable. I don't want the mime type that is describing a file to be changeable. It doesn't make sense for an instance of Music to have a Document mime type. I wrote a quick little immutable mime type.

Persisted Object Hierarchy #2

Replaces Persisted Object Hierarchy.

Meta-Data

• Item
• Image
  • Photo
• Audio
  • Music
• Document
• Contact
• Meeting
• Association
  • Dynamic Association
  • Static Association

Dynamic Association Meta-Data

Dynamic Association

extends Association extends Item.

query

[a persisted query]

Static Association Meta-Data

Static Association

extends Association extends Item.

Read/Write
relation	Collection <>	(promoted to r/w)
representative	Item

Association Meta-Data

Association

extends Item.

Read Only
relation	Collection <>

Document Meta-Data

Document

extends Item.

Defined by Data
words	int
sentences	int
paragraphs	int
pages	int	???
Read/Write
status	{ WORK_IN_PROGRESS, DRAFT, FINAL, ABANDONED }
contributors	Collection <>
keywords	Collection <>
abstract	String

Meeting Meta-Data

Meeting

extends Item.

Meeting is based on the vEvent object in the iCalendar format as described in RFC 2445 (HTML).

Reference implementation: iCal4j.

summary	String
description	String
agenda	Document	(added)
minutes	Document	(added)
material	Collection <>	(added)
comments	Collection <>
start	Date
end	Date
location	Address
status	{ TENTATIVE, CONFIRMED, CANCELLED }
organizer	Contact
attendees	Collection <>
lastMeeting	Meeting	(added)
nextMeeting	Meeting	(added)

Attendee
attendee	Contact
role	{ CHAIR, REQ-PARTICIPANT, OPT-PARTICIPANT, NON-PARTICIPANT }	ROLE
status	{ NEEDS-ACTION, ACCEPTED, DECLINED, TENTATIVE, DELEGATED }	PARTSTAT
delagatedTo	Attendee	delegateTo
delagatedFrom	Attendee	delegateFrom

Contact Meta-Data

Contact

extends Item

Contact is based on the vCard specification. Vcard is formalized in RFC 2425 (HTML) and RFC 2426 (HTML). See Vcard as RDF/XML, hCard for more info.

Reference implementation: vCard4j.

Read/Write
name	Name	N
nicknames	List <>	NICKNAME
photo	Photo	PHOTO
birthday	Date	BDAY
addresses	Collection <>	ADR
telephone	Collection <>	TEL
email	Collection <> (TODO: should there be TYPEs for this?)	EMAIL
url	URL	URL
title	String	TITLE
role	String	ROLE
agent	Contact	AGENT
organization	String	ORG
unit	List <>	ORG

Name
family	String
given	String
additional	List <>
prefix	List <>
suffix	List <>

Address
type[]	{ dom, intl, postal, parcel, home, work, pref }
poBox	String
extended	String
street	String
city (locality)	String
state (region)	String
postalCode	String
country	ISOCode

Telephone
type[]	{ home, work, msg, voice, fax, cell, video, pager, bbs, modem, car, isdn, pcs, pref }
number	String (vcard recomends canonical)

Photo Meta-Data

Photo's meta-data is based on the EXIF specification and the IPTC spec.

EXIF

See the EXIF v2.2 spec and sample data.

IPTC

IPTC IIM v4.1 spec.

Refernece implementations

• How to read EXIF and IPTC with Java Image I/O API
• Java Image I/O
• metadata extraction in java

Photo

extends Image extends Item

Read Only (exif)
Camera	Camera
Exposure Time	float
F Number	float
Original	Date
Digitized	Date
Shutter Speed	float
Aperture	float
Exposure Bias	float
Max Apature	float
Subject Distance	float
Metering Mode	{ unknown, Average, CenterWeightedAverage, Spot, MultiSpot, Pattern, Partial, other }
Flash	Flash
FocalLength	float
Read/Write (iptc)
Object Name	String
Keywords	Collection <>
By Line	Collection <>
Country (primary location)	String	TODO: use ISO countries?
Province (state)	String
City	String
Headline	String
Caption	String
Read/Write (custom)
Subjects	Collection <>

Camera
Make	String
Model	String

Flash
Fired	{ Fired, NotFired }
Returned	{ NoStrobeReturnDetectionFunction, StrobeReturnLightNotDetected, StrobeReturnLightDetected }
Mode	{ unknown, CompulsoryFiring, CompulsorySupression, Auto }
Function	{ Present, NoFlash }
RedEye	{ RedEyeReduction, NoRedEyeReduction }

TODO: should these "float" values be "rationals"?

Image Meta-Data

TODO: Image is currently geared towards raster images, not vector images.

Image

extends Item

Read Only
width	int
height	int
xResolution	float
yResolution	float
resolutionUnit	{ inches, centimeters }

Music Meta-Data

The meta-data for the Music class is a subset of the ID3v2.3.0 specification. Only the most significant fileds (the ones displayed by Winamp) were kept as a proof of concept.

We are using javamusictag to handle these.

Music

extends Audio extends Item

Read/Write
Track	int	NULLABLE	TRCK
Total Track	int	NULLABLE	TRCK
Title	String	NULLABLE	TIT2
Album	String	NULLABLE	TALB
Artist	String	NULLABLE	TPE1
Year	int	NULLABLE	TYER
Genre	String	NULLABLE	TCON
Comments	String	NULLABLE	COMM
Composer	String	NULLABLE	TCOM
Original Artist	String	NULLABLE	TOPE
Copyright	String	NULLABLE	TCOP
URL	URL	NULLABLE	WXXX
Encoded by	String	NULLABLE	TENC
Overridden
Length	int		TLEN

Audio Meta-Data

Audio

extends Item

Read Only
Length	int		Length of audio in mills