What is an application platform?

mikemill — Thu, 28 Jun 2007 00:01:00 GMT

I'm working on a short paper / presentation that describes my position on what an application platform is, the services it provides, and what it does for the application developer. This is this initial outline. This doesn't talk about a specific (LOB) application platform, but instead talks about a set of requirements that a platform should meet. One of the things that started me down this path was noticing partners using the Microsoft CRM application as a platform. I'm curious to understand how other people think about this "problem" and whether there's any benefit in pursuing the definition.

I want to set the stage by talking about what I mean by "application" first. This paper will look at large-scale line of business applications. This isn't to say that productivity applications such as Office aren't applications, it's just that they're not the class of application that necessarily has this set of requirements.

Diversion

Line of business applications

Tools for automating the business process

Productivity applications

Tools for executing business tasks

Caveat

A platform isn’t useful without an application
It’s not possible to determine requirements without an application
Most people aren’t interested in buying a platform – they want an application
An application is the start, customers and partners want a solution

Then I'll talk about the necessary and sufficient requirements for a platform. I'm trying to keep this list as short as possible because most application logic tends to leak "down" into a platform thereby making the platform less applicable to other applications.

Platform services

Identity and roles
Rich type library
Security
Storage and persistence
Extensibility
Process identification and execution
Solution packaging and containment
Deployment models

Identity and roles

What is a “user” of the system?
Collaboration scenarios drive SaaS
Roles come in many flavors

Work roles (position), security roles, reporting structures

Roles are facets of an identity
Relationships between roles are primary

Rich type library

Meta-types

Constituents

party, role, relationship, contactMethod

Collaborations

collaboration, interaction, goal, participation, structuredDocument

Unstructured collateral

simpleDocument, annotation

Opaque data

Reference data, lookup tables, auditing, etc.

Data types

enumerations, elemental types, higher-level types

Security

Authorization and authentication
Security roles are privilege collections
Privileges provide access

User interface, data, process, tasks

Security roles trump work roles

Storage and persistence

Storage structure is schema independent

From an application perspective

Storage is disconnected from logic

From an application perspective

The platform controls persistence

Types DO NOT know how to persist themselves

Extensibility

Schema

Types and storage

Presentation

Navigation
Data capture
Clients and user interface

Process

Business rules (simple and compound validation)
Business logic (“big” and “little” process definition)
Process execution structures (message definitions)

Process identification and execution

Message definition and execution
Actor identification by identity and role
Task and work lists
Loosely bound to an extreme
Declarative vs. imperative
Long-running business processes
Transactional business logic
One entry point to execute processes

Solution packaging and containment

Everything is an extension

Schema, process, presentation

All extensions are named and grouped

Names are like CLR strong names

Packages are like applications or modules

Deployment models

Multi-tenancy is important
Multi-language per tenant
Presentation is independent of the platform

But the platform can provide presentation tools

Michaeljon Miller : Pure-play hosted models

What is an application platform?