Post on 03-Feb-2022
transcript
About me
• Artur Karaźniewicz - Chief Integration And Solution Architect, Integration Team Leader - Allianz Poland
• Working with Java since 1999 (JServ anybody?)
• Experience in Financial Services
First things first, but not necessarily in that order. First things first, but not necessarily in that order. -- Doctor Who-- Doctor Who
What’s an ESB?
What’s an ESBEnterprise Service Bus - term first coined by Gartner around 2002 (although few others claim They coined the term before)
(Enterprise Service Bus) Universal integration backbone. An (Enterprise Service Bus) Universal integration backbone. An ESB acts as a shared messaging layer for connecting ESB acts as a shared messaging layer for connecting
applications and other services throughout an enterprise applications and other services throughout an enterprise computing infrastructure. It supplements its core computing infrastructure. It supplements its core
asynchronous asynchronous messaging backbonemessaging backbone with intelligent with intelligent transformation and routingtransformation and routing to ensure messages are passed to ensure messages are passed
reliably. Services participate in the ESB using either reliably. Services participate in the ESB using either web web servicesservices messaging standards or the Java Message System messaging standards or the Java Message System
(JMS).(JMS).
What’s an ESBSonic Software, one of the first ESB bandwagon members has it's own definition
An ESB is software infrastructure that simplifies the An ESB is software infrastructure that simplifies the integration and flexible reuse of business components using a integration and flexible reuse of business components using a
service-orientedservice-oriented architecture. An ESB makes it easy to architecture. An ESB makes it easy to dynamically connect, dynamically connect, mediatemediate and control services and their and control services and their
interactions.interactions.-- source -- source http://www.businessreviewonline.com/blog/archives/2005/12/does_sonics_esb.htmlhttp://www.businessreviewonline.com/blog/archives/2005/12/does_sonics_esb.html
What’s an ESBIONA has little bit different perception what ESB actually is
In general we agree with Sonic's requirements for an In general we agree with Sonic's requirements for an ESB, at a technical level when it comes to how to ESB, at a technical level when it comes to how to
meet those requirements we think they have got it meet those requirements we think they have got it all wrong. [...] Specifically, he said that Iona believes all wrong. [...] Specifically, he said that Iona believes
Sonic's ESB is "overly JMS [Java Message Service] Sonic's ESB is "overly JMS [Java Message Service] and broker based".and broker based".
-- source http://www.businessreviewonline.com/blog/archives/2005/12/does_sonics_esb.html-- source http://www.businessreviewonline.com/blog/archives/2005/12/does_sonics_esb.html
What’s an ESBPolarLake, another ESB Vendor adds another view
Great to see Sonic Software's definition converge Great to see Sonic Software's definition converge towards ours. In particular, they are correctly towards ours. In particular, they are correctly
identifying that identifying that mediationmediation - a term we have used for - a term we have used for quite some time - is the core feature of an ESB.quite some time - is the core feature of an ESB.
-- source -- source http://www.businessreviewonline.com/blog/archives/2005/12/does_sonics_esb.htmlhttp://www.businessreviewonline.com/blog/archives/2005/12/does_sonics_esb.html
Odd that we think definitions are definitive. Odd that we think definitions are definitive. -- Larry Wall, Perl Creator-- Larry Wall, Perl Creator
So what’s ESB after all?
So What’s an ESB, after all?
Messaging BackboneMessaging Backbone
Routing and mediationRouting and mediation
WS StackWS Stack Adapters/ConnectorsAdapters/Connectors
Legacy SystemsLegacy Systems
• A little bit of distribution mechanisms
• Bus Architecture vs. Hub And Spoke
• Strong monitoring and management capabilities
• With little pinch of flexibility...
So What’s an ESB, after all?
What ESB is not?• It’s not an Application Server!
• It’s not centralized nor monolithic
• It’s not BPMS (Business Process Management Suite)
• It’s not MOM
For every complex problem, there is a solution that is simple, For every complex problem, there is a solution that is simple, neat, and wrong.neat, and wrong.
-- Henry Louis Mencken -- Henry Louis Mencken
What’s wrong with ESB, then?
What’s wrong with ESB?
• It looks Great!..
• ...But in practice - most ESBs are typical 80/20 solutions (or simple, neat and wrong)
• 80% of (simple) things are very easy to implement using of the shelve ESB
• 20% of things are extremely difficult to implement using of the shelve ESB
We have 80% of Perl6 done and we are now working on the next 80%.We have 80% of Perl6 done and we are now working on the next 80%.-- Anonymous Coward, slashdot.org, Perl 6 discussion-- Anonymous Coward, slashdot.org, Perl 6 discussion
Examples?Excerpt from (some) ESB documentation
The Oracle Database adapter does not The Oracle Database adapter does not support the following data types: support the following data types: * PL/SQL TABLE * PL/SQL TABLE * TABLE * TABLE * VARRAY * VARRAY * OBJECT* OBJECTetc..etc..
Examples?Excerpt from (some) ESB documentation
The Oracle Database adapter accepts a The Oracle Database adapter accepts a character data for a NUMBER field character data for a NUMBER field without throwing an error. In the without throwing an error. In the database, the character is stored as 0.database, the character is stored as 0.
What’s wrong with ESB?
• Lack of sound community• “Community driven” vs. “consultants driven”
• Extremely proprietary solutions
• Proprietary extensions to standards
No standard or clause in a standard has a divine right of existenceNo standard or clause in a standard has a divine right of existence-- -- A Microsoft PKI architect explaining Microsoft's position on standards compliance.A Microsoft PKI architect explaining Microsoft's position on standards compliance.
What’s wrong with ESB?
• Focused on Vendor Background• Application Servers Vendors base their ESB on their
Application Servers
• EAI Vendors base ESB on their EAI
• Messaging Vendors base ESB on Message Brokers
• Some solutions became ESB for one night...
The trouble is that things The trouble is that things nevernever get better, they just stay the same, only more so. get better, they just stay the same, only more so.-- Terry Pratchett, "Eric" -- Terry Pratchett, "Eric"
Steve Vinoski, chief engineer of product innovation for IONA
Frankly, if I were an enterprise architect today, and I Frankly, if I were an enterprise architect today, and I were genuinely concerned about development costs, were genuinely concerned about development costs,
agility, and extensibility, I’d be looking to solve agility, and extensibility, I’d be looking to solve everything I possibly could with dynamic languages everything I possibly could with dynamic languages and REST, and specifically the HTTP variety of REST. and REST, and specifically the HTTP variety of REST. I’d avoid ESBs and the typical enterprise middleware I’d avoid ESBs and the typical enterprise middleware
frameworks unless I had a problem that really frameworks unless I had a problem that really required them (see below). I’d also try to totally required them (see below). I’d also try to totally
avoid SOAP and WS-*.avoid SOAP and WS-*.
What’s wrong with ESB?
The ESB check list• Contract first development• What does this mean
• Why it’s important?
• Agility• Test Driven Development
• Contiguous Integration
• “Mockability”
The ESB check list• Standard compliance• WS-* standards compliance (beware of Vendor’s bias!)
• Interoperability
• WS Stack standard compliance
• Flexibility• REST
• SOAP
• Sound Community
My opinions may have changed, but not the fact that I am right.My opinions may have changed, but not the fact that I am right. -- Ashleigh Brilliant -- Ashleigh Brilliant
CXF the ESB framework
What's CXF
• IONA Celtix + Codehouse XFire = CXF
Celtix Celtix isis an Open Source, Java an Open Source, Java Enterprise Service BusEnterprise Service Bus and hosted in the ObjectWeb community.and hosted in the ObjectWeb community.
-- http://www.iona.com, in 2006
While Celtix has traditionally called itself an ESB, if you While Celtix has traditionally called itself an ESB, if you look at the code you'll see that Celtix has primarily look at the code you'll see that Celtix has primarily
focused on providing JAX-WS and WS-* support. The focused on providing JAX-WS and WS-* support. The new project will new project will NOTNOT be branded as an be branded as an ESBESB..
-- http://xfire.codehaus.org/XFire+and+Celtix+Merge
What’s CXF?• JAX-WS certified stack
• Commercially Supported IONA
• Embeddable stack
• J2EE containers (BEA WLS, JBoss, IBM WebSphere, Tomcat, Oracle iAS, Apache Geronimo etc. )
• JBI (Apache Service Mix)
• Standalone Spring Container
What’s CXF?● WS-* compliant stack
● WS-Addressing,
● WS-Policy,
● WS-ReliableMessaging
● WS-Security
● Fully integrated with Spring● REST enabled framework through
JAX-RS and HTTP binding
CXF architecture
Messaging / InterceptorsMessaging / Interceptors
BusBus
Front-endsFront-ends
JAX-WSJAX-WS SimpleSimple
BindingsBindings
JAXBJAXB
AegisAegis
TransportsTransports
JMSJMS
HTTPHTTP
LocalLocal
JAX-WS Architecture
ToolingTooling
JAX-WSJAX-WS
JAXB 2JAXB 2 SAAJSAAJ
•JAX-WS – Java API for XML WS• JSR 224 (java.xml.soap)• Web Services metadata JSR 170 (java.jws)• ••
•JAXB Java XML Binding API• JSR 222 (java.xml.bind)• • ••
•Tooling•WSDL to Java•Java to WSDL•etc...• • ••
•SAAJ•SOAP with Attachments API for Java• • ••
CXF ArchitectureHow does CXF fit into ESB landscape?
Routing and mediationRouting and mediation
WS StackWS Stack Adapters/ConnectorsAdapters/Connectors
Messaging BackboneMessaging BackboneMessaging BackboneMessaging BackboneMessaging BackboneMessaging Backbone
CXFCXF
Hello World, CXF Way
• Look Ma! no XML, no generated artefacts!
• POJO service
• Dead simple! Even Your Grandma’ can do it!
• Up and running - in just 19 lines of code!
What’s Wrong with this Example?
• It’s not contract first
• It’s just remoting
• It runs in built-in HTTP container
Real-world CXF Webservices
• What's wrong with this service?
• No value constructors
• No toString, hashCode and equals
● XMLGregorianCalendar?
● No validation
● No Security
Real-world CXF Webservices
• Customizing JAXB binding via xjc plugins
• Jakarta Commons Plugin
• Value Constructor Plugin
● Simple Preserve Plugin
● Value Constructor Plugin
● More on:
● https://jaxb2-commons.dev.java.net/
Real-world CXF WebservicesMonitoring and managing CXF● Built-in JMX monitoring and managing
module● Exposing custom components
There are only two tragedies in life: one is not getting what one There are only two tragedies in life: one is not getting what one wants, and the other is getting it.wants, and the other is getting it.
-- Oscar Wilde-- Oscar Wilde
Consuming Services
Consuming Services• Generate Stubs from WSDL, as before
• Use generated Client Stub
• Disadvantages
• No CXF fine-tuning
• Bloated client
• No Spring integration
There are only two tragedies in life: one is not getting what one There are only two tragedies in life: one is not getting what one wants, and the other is getting it.wants, and the other is getting it.
-- Oscar Wilde-- Oscar Wilde
Testing Services
Testing services• Service implementation is just POJO
• Service can be exposed using Endpoint.publish and consumed as a standard endpoint
• Leads to problems with CI servers
• Services can be exposed through CXF convenient API, and through local:// (in VM) transport
Do we need ESB?• In complex scenarios... yes!
• But maybe You have one already?
• Check something that works for You
• Use ESB Check List when selecting concrete solution
• Try to avoid Vendor Lock-in
• Community is important!