Spring MEUnleashing Spring to the Rest of the Platform

Wilfred SpringerXebia, The Netherlands

Audience

3

Agenda

> Why this talk?> Why Spring?> Why not Spring?> How Spring?> Under the hood> Alternatives> Current status & what's next?> Discussion

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Java is doing AWESOME!

Source: Tiobe Programming Community Index March

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Spring is doing GREAT!

Source: Evans Data, 2008

+ =

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But that's like... a freaking big number

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… or is it?

SAN MATEO, Calif.—November 19, 2008 – SpringSource, a leading provider of infrastructure software and the company behind Spring, the de facto standard in enterprise Java, today announced that results from an extensive Evans Data research study reveal large scale adoption and penetration of Spring as a means of increasing developer productivity and

combating complexity in today’s enterprise application infrastructure market.

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Java Nodes in the Cloud

> 3 Billion Java-Enabled Cards in 2007> 1.8 Billion Java-Enabled Phones in 2007> 7 Million Java Set-top Boxes> 1 Million GWT downloads in 2007> Sun SPOT> Livescribe Smartpen

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Not all men are equal

versus

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Spring ME Manifesto

“We hold these truths to be self-evident, that all men … Java Developers are entitled to get

their portion of Spring goodness.”

Not just Java EE developersNot just Java SE developers

But also Java ME, GWT developers and Java Card developers

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Why Spring?

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IoC/Dependency Injection

“Trust us, we know what we're doing.”“Don't call us, we call you.”

Instead of this Take hard-wired dependencies out

And have a frameworkconnect them together

AOP (Cross-cutting behavior)

Sanitized API

“Any problem in computer science can be solved with another layer of indirection.”

– David Wheeler

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Why not Spring?

So why not have Spring?

Platform Limitations> Limited Java Runtime capabilities> Limitations imposed by deployment> Limited computational resources

● Limitations on heap● Limitations on application size● Limitations on performance

Java Runtime Limitations

GWT n n n y y yJava ME y y n y y nJava Card n n n n n n

Class.fo

rName(..

.)

Class.newInsta

nce()

Other java

.lang.re

flect

java.la

ng.Strin

g

char

java.util.

List

BeanFactory#getBean(String name)?BeanFactory#getBean(char[] name)?

Deployment Limitations

<bean id=”movie1” class=”sample.Movie”> <property name=”title” value=”Into the Wild”/></bean>

package com.mgm;

public class Movie { void setTitle(String title);}

package a.b;

public class a { void a(String ...);}

<bean id=”movie1” class=”a.b.a”> <property name=”a” value=”Into the Wild”/></bean>

OBFUSCATION

1

2 3

4

Heap

> Java SE● Max heap approx. 1.5 GB

> Java ME● Lower bound max. heap: 140 KB● Upper bound max. heap: 128 MB● Between factor 11 and 11,714 difference

> Java Card● 16 K RAM

Application Size

> Java ME: Upperbounds between 64 KB and 28 MB

Spring Core 267KBSpring Beans 467KBSpring Context 455KBTotal 1189KB

Throughput

> Nokia E71:● 369 MHz ARM 11 CPU

> Gameboy Advance● 16 MHz ARM 7 CPU● C-Ray Raytracing Benchmark 296108 s

> Dell PowerEdge M710● 2.4 GHz Xeon Quad Core CPU● C-Ray Raytracing Benchmark 201 s

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How Spring?

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Introducing Spring ME's IoC

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Introducing Spring ME's IoC

Do most of the hard work at build time

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Suppose this is the object model

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And you want to create these instances

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Then this is the Spring ME Configuration<beans xmlns=”…”> <bean id=”movieFinder” class=”….InMemoryMovieFinder”> <property name=”movies”> <list> <bean class=”….Movie”> <property name=”title” value=”Bye Bye Blue Bird”/> <property name=”director” value=”Søren Kragh-Jacobsen”/> <property name=”year” value=”1999”/> </bean> … </list> </property> </bean></beans>

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With this Maven plugin configuration<project> <build> <plugins> <plugin> <groupId>me.springframework</groupId> <artifactId>spring-me-maven-plugin</artifactId> <version>1.0</version> <executions> <execution> <goals> <goal>generate</goal> </goals> <configuration> <contextFile>....context.xml</contextFile> <className>com.mgm.BeanFactory</className> </configuration> </execution> </executions>

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Generates this BeanFactory

public class BeanFactory { public Object getBean(String name) { if (“movieFinder”.equals(name)) { return getMovieFinder(); } } private final Object getMovieFinder() { … } …}

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DEMO

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DEMO (Java ME)

> Spring ME on Java ME

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DEMO (Java ME)

> A little more Spring alike

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DEMO (Java SE)

public interface MinimalBeanFactory{ Object getBean(String name) throws BeansException;}

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DEMO (Java SE)

Additional benefits

> Compile time validation● “Is 10e2 a valid int representation?”● “Is an instance of Boeing747 assignable to a

property of type Airplane?”> Minimal or no runtime dependencies> Superfast (but no benchmarks to verify this)> Small (1K?)

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Under the hood

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Spring ME Meta Model

Spring XMLConfiguration

Spring MEMeta Model

Spring ME BeanFactory

> Meta Model independent of Spring> Typically Spring XML configuration is used

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Other sources?

Spring MEMeta Model

Spring ME BeanFactory

Annotations

@Autowired@PostConstruct@PostDestroy

@ProvidedBy@Inject@ImplementedBy

Spring XMLConfiguration

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Spring ME's Meta Model

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Spring ME Meta Model Snapshot

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Alternatives

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Inversion of Control Galore

Rocket GWT y n y y y y y y y y n y n n all y y y n nSpring ME y y y y y y y y y y n n y n l/m y y y y* y*

n y y n n n n n n n n n n n ... y n n y yFall ME n y y n n n n n n n n n n n ... y n n n n

y n y y y y ? y y n y y n n all n y n y ySignal n n y y n n ? n n n n n y n all n y y ? ?

Israfil IoC

GWToolbox

GWTJa

va M

E

Singletons

Prototyp

es

LazyEager

Factory

methods

Init method

Destroy m

ethod

XML config

uration

Annotation con

figuratio

n

Property

placeholders

Spring C

ompatible S

yntax

AliasColle

ctions*

Constructo

r injectio

n

Property

injecti

on

Wire

by name

Autowire by t

ype

Autowire by n

ame

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Sanitized API

> Java ME needs a lot more sanity● J2ME Polish is your friend

> Java Card is probably too limited to use wrapper APIs

> GWT is already addressed by a lot of frameworks

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AOP

> What about it?> Compile team weaving?> Using the metadata, AOP proxies could be

constructed at build time> The factory could construct instances of these

proxies instead of the actual objects

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Current Status and What's Next

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Current status

> 'Request' scope

> 'Session' scope

> 'Global session' scope

> BeanFactoryAware, but ...

> BeanPostProcessor (without reflection?)

> BeanFactoryPostProcessor, but ...

> FactoryBean, but ...

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If there's only one thing you remember

> “ME” as in “supporting Java ME”> “ME” as in “a microscopic small version of Spring”> Useful for Java ME> Useful for GWT> Useful for Java SE> Potentially useful for Java Card and Java EE

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Other than that

> Version 1.0 just released> GPL + Classpath Exception> Integration with J2ME Polish> JSR 296 on ME> http://springframework.me/> spring-me@googlegroups.com

Wilfred Springerwilfred at flotsam.nl

http://springframework.me/