Software Product Lines Peter Bell CEO/CTO, SystemsForge cf.Objective() 2008 Peter Bell CEO/CTO, SystemsForge cf.Objective() 2008.

Software Product LinesSoftware Product Lines

Peter BellCEO/CTO, SystemsForge

cf.Objective() 2008

Peter BellCEO/CTO, SystemsForge

cf.Objective() 2008

Who Am I?Programmer - 30-50 projects/yr.

Researcher - Published academic papers DSM forum/ooPSLA

SystemsForge - 10,000 custom apps/yr.

Writer - CFDJ, Fusion Authority Quarterly

Presenter - cf.objective(), CF United, Frameworks, Code Generation 2007, ooPSLA, Domain Specific Modeling Forum, CFCamp . . .

What is a SPL?

“framework for systematic reuse”

“ predictive versus opportunistic software reuse”

5-10 times improvements in productivity

Why NOT Use?

Not thought of it

Too busy

“We're special”

Sales model

Hourly billing

Client expectations

It’s Not Just CodeCandidates for Reuse:

Methodology

Contracts

Requirements

Architecture

Tests

Documentation

Tooling

Layers of Reuse

Feature model - major items - shopping cart

Configuration - bounded variability - shipping options

DSLs - unbounded variability - objects and screens

Custom code - one offs - custom integration

What IS a DSL?

“An executable language targeted to a specific problem domain”

Specific - can’t do everything

Executable - not just conceptual

Raising level of abstraction

Everything is a DSL

Premise: EVERYTHING is a DSL

Useful if not true!

Examples:

API

Database schema

XML file

Object (methods with parameters)

“When I use a word, it means just what I choose it to mean”

- Humpty Dumpty

Abstract vs. Concrete

Abstract Grammar vs. Concrete Syntax

What you say vs. How you say it

User@FirstName

<Object title=”User”> <Name>FirstName</Name></Object>

Internal vs. ExternalAPI:

UserService.import("test.csv", ",", "FirstName,LastName,Email", "tbl_User", "update");

Internal

Language extension:

steps_for(:accounts) do

Given("my $account_type account balance is $amount") do |account_type, amount|

create_account(account_type, amount)

end

When("I transfer $amount from $source_account to $target_account") do |amount, source_account, target_account|

get_account(source_account).transfer(amount).to(get_account(target_account))

end . . .

Internal vs. ExternalXML:

<import filename="test.csv" record-delimiter="," field-name-list="FirstName,LastName,Email" source="tbl_User" method="update" />

External

Comma Delimited:

"test.csv", ",", "FirstName,LastName,Email", "tbl_User", "update"Little Language:

Import test.csv using commas update tbl_User with FirstName,LastName,Email

Databased

Visual

Horizontal vs. VerticalHorizontal (tech focused)

SQL

RegEx

Import description language

General workflow language

Vertical (business focused)

Insurance policy language

Product configuration language

Academic requirements language

ProjectionsAPI: technical reuse

XML: semi technical, good for I/O and transforms

Visual: semi technical, gives “sense” of system

Database: reuse/cms

<?xml version="1.0" encoding="UTF-8"?><controller>

<title>Search</title><name>Search</name><defaultAction>viewCategory</

defaultAction><actions>

<detail name="viewCategory" object="ProductCategory" method="getByID" PropertyValueList="%Input.CID%" screen="product-catalog-category-detail" />

<detail name="viewProduct" object="Product" method="getByID" PropertyValueList="%Input.PID%" screen="product-catalog-product-detail" />

<display name="displaySearchResults" Data="" screen="product-catalog-search-results" />

</actions></controller>

Top down vs. Bottom up

Top down - Domain concepts

Bottom up - repeating patterns

Generation vs. SynthesisGeneration: Saving code files to disk

Synthesis: Processing DSL dynamically

Compilation vs. Interpretation

Late bound decision

Why Generate?

Language limitations

IP protection

Performance (proven issue)

Adding Custom Code

Inheritance

AOP

Mixins

Extension points (observer)

Protected Blocks

Getting Started

Agile approach

Not just code

Bottom up and top down

Systematic process - schedule it in

Questions?

Blog: www.pbell.com

Email: [email protected]

Email: [email protected] - Yahoo: freshstartsw - AIM: appgeneration