Enterprise-Level Code Generation

Matthew Fowler

Agenda

1. Introduction• JeeWiz V4 - Process and Techniques• What's changed• JeeWiz V5 Worked Example

NT/e

• NT/e– New Technology / enterprise– Formed 1996

• 1998 - Server-side Java. BEA Partners• 2006-7: £2.5m turnover, £100k profit• JeeWiz Version 1.0: March 2002• JeeWiz Version 5.0.9: June 2008• Key relationships: DeutschePost/SOPERA,

BEA, GigaSpaces

What's ELCG

• Java, XML, Ant, Scripting– Develop on Windows, deploy on UNIX

• Commercial/industrial– As opposed to defense/telecom (MDA)– Microsoft different too

• Commercial drivers: – Opportunity: ROI, cost reduction, business agility– Defensive: stability, buy products, multiple

stakeholders

2. JeeWiz V4 Process & Techniques

1. Meta-model

2. Build profiles

3. Model

4. XMI → Simple XML

5. Generation

6. Writing code

(2.1) Meta-modelling Features

• Meta-model, meta-class, properties, lists• Validation - required, unique, Java expr• Factors - sort of mix-ins• Automatic generation of getters/setters/lists• Multi-level: i.e. "metaModel:metaClass" to

reference across models• Add special methods in Java as XML CDATA• Lists for all descendants - class, b-o, entity

Sample Meta-model

<meta-class name="entity"

extends="attribute-collection"

factor="security-factor" >

<description>...</description>

<property name="table-name" />

<property name="container" />

<list name="query /">

<validator expression="!getStatic()" message="An Entity must not be static"

/>

<![CDATA[

public int getPositionWithinParent()

{

return 30;

}

]]>

</meta-class>

Bottom line

• Quick - 1-2% of effort on meta-modelling• Powerful• HTML/Eclipse docs generation• Even better when you don't have to use it

– JeeWiz can generate without a meta-model

(2.2) Build Profiles

Base

Java

Bizobject

Screen

Collapse

1-levelMeta-model

Universal Automated

Powerful

Flexible

filter.xml

CustomisedMeta-model

Filter

RSM: JeeWiz.epx

Universal Automated

Powerful

Flexible

Universal Automated

Powerful

Flexible

Format

Build Profiles (cont.)

• Filter allows – easy customisation– consistency with meta-model enhancements

• Phase 3 changes for different modelling tool– same modelling profile across tools

(2.3) Modelling

• Logical-level concepts: e.g. page; event– All the platform representation is generated

• High-value "styles"– multi-patterns for generating look/behaviour– intention hints, cross-cutting

• RSM: automatic of deduction of stereotypes– Saves lots of fiddling and finger-trouble– Rewrite back to model possible

• Tolerance: fill in the blanks with M2M

Modelling Tolerance:Entity Key Generation

#if( $keys.size() == 0 ) ### if there are no keys### generate an autokey object on this entity

<this><attribute name="oid" autokey="true" type="Integer" />

</this>#end

• An example of technique + best practice

Page Modelling in RSM

Entity Modelling in RSM

Modelling In Gigaspaces

(2.4) XMI → Simple XML <entity name="Customer"/>

<attribute name="AcctID" type="String"/></entity>

• As simple as possible - it's all intentional• Lowest common denominator - for exchange

– Use JeeWiz on any XML– On read-in, no meta-model needed

• #foreach( $attribute in $entity.attributeList ) $attribute.name ...#end

• CDATA in <class> carries code

(2.5) Generation 1 - M2M

Model(text)

Model(Java objects)

M2Text

CodeConfig

M2M

+Velocity+

Velocity+

– Automated design patterns, plus code

– Same Enhanced Velocity: M2M Language = Velocity + XML

– Output is Simple XML - feedback loop

• No PIM/PSM dichotomy, no separate stage

– Automatic building of result - no configuration

– Separation of M2M from rendering to platform

– 30:1 to 50:1 expansion of model

+

Entity Key Generation - application of M2M

#if( $keys.size() == 0 ) ### if there are no keys### generate an autokey object on this entity

<this><attribute name="oid" autokey="true" type="Integer" />

</this>#end

Generation 2 - Automatic Build

• "Visitor" Tree Walk– Manufacturing assemblies– Run ant if build.xml exists– No further configuration– Automatic build of M2M output

• Ant - Model Integration– Read properties– Direct output to model– Side effects on model

• Builds become components

application name="Accounting"

ejb-jar name="Accounting1"

entity name="Account"bean-managed="false"

attribute name="accountId"type="int"

ejbJarList

attribute name="title"type="String"

entityList

attributeList1 2

3

4

5

Generation 3 - M2Text

• Called with special Ant task from a give object <jwVelocity template="applicationXml.vm"

file ="${staging}/META-INF/application.xml"

/>

• Velocity script language– Well known, easy to use– Links to Java

• JeeWiz additions: – Velocity methods– 240 Java helper methods

Generated Architecture

• HTML, CSS, JSP, Struts, some JavaScript• Session EJBs and Web Services• EJB 2.1 CMP• Application servers:

– JBoss, Websphere, WebLogic, WebSphere

• Databases: Oracle, SQL Server, MySQL

(2.6) Writing Code• 3-7% by volume in WebApps• Written in base language - Java• Uses 'extends' strategy• Pluggable weaving

implementationsImplementation Code

class Impl extends Base {

}

/* UID: ... */int mImpl {... }

Generated Code

class Base {

}

int mBase {... mImpl();}

Application Page

Application Page 2

And Another Thing

• CRUD generation– Relatively simple patterns

• Data-views– Intermediate objects between DB and

user/GUI or service API– Trees of objects, map to multiple database: a "view"– 25% of effort/volume

• Antlr V3 Example - using JeeWiz as a compiler backend

Summary: JeeWiz V4 - Process and Techniques

• Modelling - precise, high-level, smart defaults• Fast iterations - supports reqts. discovery• Encoding of techniques, architecture, custom

conventions, best practice• Automatic UI generation from abstract models• Coordinated multi-tier - 93-97% generation

– Struts, J2EE, Web Services, mid-tier views

• Commercial license, per-seat charge• Fundamentals known by millions of developers

3. What's Changed?

• Version 5: Taking pluggability to another level– R&D grant commitment

• Changes in the external world:– Virtualisation, clouds, SOA, grid computing– Hibernate/lightweight containers– Ajax, more Web frameworks than programmer

• No longer "One UI"

• Sopera - Eclipse "Swordfish" includes JeeWiz

Problems

• Cost of integration– New stack: Trinidad, JSF, Spring, Hibernate– The 500-page books are just the starting point

• Multiple viable UI frameworks– Struts, Struts2, JSF, Javascript libraries, Seam– No clear winner

• Making money - the value chain– Too much technology, too little time

Ecosystem relationships

Technology ProviderPartner

JeeWiz.com End-user

Language/region Partner

Add-onTechnology

ProviderPartner

Value-addPartner

(SI, Appln Product)

JeeWiz.org

e.g. Hibernate

e.g. Ajax Library

4. JeeWiz V5 Worked Example

(4.1) A Framework for Software Factories

Base

Java

Business Objects

Persistence

Hibernate

Database

Screen

JBoss4

JSF

Demo

Custom

Meta-ModelSystem Properties

Per-objectProperties M2M M2Text Controls

What is a control?• A non-model object• Properties• Velocity methods• Normal overriding/inheriting• Used for details

Ant representationtemplateDir=${basedir}/control,

${jwhome}/resources/demo/control,

${jwhome}/resources/jsf/control,

${jwhome}/resources/jboss4/control,

${jwhome}/resources/screen/control,

${jwhome}/resources/${database}/control,

${jwhome}/resources/hibernate/control,

${jwhome}/resources/persistence/control,

${jwhome}/resources/bizobject/control,

${jwhome}/resources/java/control,

${jwhome}/resources/base/control

• Abstract layers versus implementation layers– Factor out PIM-level implementation

• Other aspects of configuration pulled in from know files

(4.2) Problem Statement

Attribute

type=String

DB Column

BigInt

Presentation-

(nnnnn) mmm mmm

User View

Programmer View

ORM View

?

DatabaseView

Java-to-SQL-typeString Long

The Framework Angle

Base

Java

Business Objects

Persistence

Hibernate

Database

Screen

JBoss4

JSF

Demo

Custom

Meta-ModelSystem Properties

Per-objectProperties M2M M2Text Controls

javaSqlType

javaSqlType

javaSqlTypeConverter

javaSqlTypeStringLong

Split of Reponsibities

Persistence javaSqlType

ORM-independent knowledge

based on datatype

Hibernate javaSqlType

Mapping datatype->ORMtype

Persistence javaSqlTypeConverter

Wrap expressions in statements

Custom javaSqlTypeStringLong

Map String to Long

The Custom Control#extends( javaSqlTypeConverter )

languageType = Long

isNumeric = ${booleanTrue}

toSqlException = NumberFormatException

#method( toSqlExpression- $attribute $var )

#return( "Long.parseLong( $var )" )

#end

#method( fromSqlExpression- $attribute $var )

## flesh this out to 11 characters - use String formatter

#return( "String.format( ${q}%011d${q}, $var )" )

#end

#method (getInternalTypeFromRS $resultsSet $col $attribute)

#return( "${q}${q} + ${resultsSet}.getLong( $col )" )

#end

(There's not much fluff here)

Control Types

PhysicalDataTypes

LogicalDataTypes

Java-SQL Types

Logging

Database

Java-SQL Types(Hibernate Extn)

Language

Database(Hibernate Extn)

UI Field UI Search Field UI Navigation

Lookups - Style, datatype

UI State

Conversation management,stacking

UI Field(JSF/Trinidad)

UI Search Field(JSF/Trinidad)

UI Navigation(JSF/Trinidad)

UI State(JSF/Trinidad)

UI End...

Attribute

type=String

DB Column

BigInt

Presentation-

(nnnnn) mmm mmm

User View

Programmer View

ORM View

?

DatabaseView

(00000) 000 000 00000000000

The uiFieldPhoneNumber Control

• Similarity to java-Sql converter:

#extends(uiFieldDisplayConverter )

toUiException = RuntimeException

#method(toUiStatements- $attribute $var )

...

#end

#method( fromUiStatements- $attribute $var )

...

#end

• Minimal amount for enhancer to write• Easy basics; easy to copy - commercially viable

(4.3) Commercial

• What we're doing is building a framework so that people can add in their own set of controls– JeeWiz: Generic UI Controls Architecture

• e.g. selection by name, or datatype, or style

– JSF Guru: JSF basic; Custom converters etc.– Apache Trinidad: Trinidad controls– Ajax Library: Ajax controls, Javascript Library– VARs/End users: Override with local style

• On the Web today - jeewiz.org

End