SOA using Java Web Services and Ajax

1
SOA using Java Web Services and Ajax

• Mark D. Hansen
• Author of SOA Using Java Web Services
• http//soabook.com

2
Mark Hansens Background

• Consultant, Entrepreneur, MIT PhD
• Book and code examples at http//soabook.com
• SOA-J open source project at http//soa-j.org

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Outline

• What is SOA?
• What are Web Services?
• What are Java Web Services (JWS)?
• What is AJAX?
• How can you implement SOA with JWS and AJAX?
• Demo (eBay, Amazon, Yahoo!)

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What is SOA?

• Loose coupling
• Service contract
• Autonomy
• Abstraction
• Reusability
• Composability
• Statelessness
• Discoverability

Service-Oriented Architecture, Thomas Erl,
Chapter 3 pg 34 - 37
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What is a Web Service?

• A provider that enables access to the service via
  either
• SOAP
• XML / HTTP
• A description or contract that specifies the
  request/response message structure.
• WSDL
• XML Schema (insufficient)
• WADL (new)

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What are Java Web Services (JWS)?

• The provider is written in Java and deployed
  using a Java container.
• The consumer is written in Java.
• Java Web Service APIs are used
• JAX-WS
• JAXB
• WS-Metadata (JSR-181)
• WSEE (JSR-109)
• JAX-RPC is deprecated starting in Java EE 5

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Client Side JWS
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Server Side JWS
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JAX-WS Maps WSDL to a Java API

• package samples
• import javax.jws.WebService
• _at_WebService
• public class Hello
• public String sayHello(String s)
• return "Hello " s

• ltdefinitions ... targetNamespace"http//samples/"
  name"HelloService"gt
• lttypesgt ... lt/typesgt
• ltmessage name"sayHello"gt ... lt/messagegt
• ltportType name"Hello"gt
• ltoperation name"sayHello"gt
• ltinput message"tnssayHello"/gt
• ltoutput message"tnssayHelloResponse"/gt
• lt/operationgt
• lt/portTypegt
• ltbinding name"HelloPortBinding"
  type"tnsHello"gt
• ltsoapbinding ... /gt
• ltoperation name"sayHello"gt ... lt/operationgt
• lt/bindinggt
• ltservice name"HelloService"gt
• ltport name"HelloPort ...
• lt/portgt
• lt/servicegt
• lt/definitionsgt

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JAXB Maps XML Schema to Java Classes
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What is AJAX?

• Asynchronous JavaScript and XML
• An Interaction Model
• A Set of Technologies for Rich Client Development
• ...
• A Composite Application Framework for Flexible
  Business Process Management ???

Ajax In Action, Dave Crane et al., Chapter 2 pg
33
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SOA Using JWS and Ajax
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SOAShopper Architecture
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Demo

• SOAShopper Integrating Yahoo!, Amazon, and eBay

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eBay WSDL
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Ant Task to Compile eBay WSDL
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Using the Generated eBay API
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A Client Binding Example

• public ListltOffergt offerSearch(
• String keywords, Category category,
• Price lowprice, Price highprice)
• ShopperImp binding
• BindingService.getBinding(
• ShopperImp.class, EBayAPIInterface.clas
  s)
• return
• binding.offerSearch(keywords,
• category, lowprice, highprice)

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Implementing a Binding Service

• public abstract class BindingService
• public static ltCgt C getBinding(
• ClassltCgt client, Classlt?gt service)
• ...

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Flash Demo
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Using the Dojo Table Widget

• lttable dojoType"filteringTable"
  id"fromSOAShopperData" multiple"true"
• alternateRows"true" cellpadding"0"
  cellspacing"0" border"0"
• style"margin-bottom24px"gt
• lttheadgt
• lttrgt
• ltth field"source" dataType"String"gtSourcelt
  /thgt
• ltth field"thumbnail" dataType"html"
  align"center"gtImagelt/thgt
• ltth field"price" dataType"String"gtPricelt/t
  hgt
• ltth field"summary" dataType"String"gtSummar
  ylt/thgt
• ltth field"url" dataType"html"gtLinklt/thgt
• lt/trgt
• lt/theadgt
• lt/tablegt

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Invoking the REST Endpoint

• function retrieveURL(url)
• restURL url
• showSearchingMsg(restURL)
• if (window.XMLHttpRequest) // Non-IE
  browsers
• req new XMLHttpRequest()
• req.onreadystatechange processStateChange
  
• try
• req.open("GET", url, true)
• req.setRequestHeader('Content-type','text/
  xml')
• catch (e)
• alert(e)
• req.send(null)
• else if (window.ActiveXObject) // IE
• req new ActiveXObject("Microsoft.XMLHTTP")
  
• ...

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Loading the Dojo Table

• function populateTableFromLiveSOAShopperData()
• try
• var w dojo.widget.byId("fromSOAShopperData")
  
• w.store.setData(theSOAShopperLiveData)
• catch(e)
• alert(e)

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Resources

• SOA Using Java Web Services http//soabook.com
• Thomas Erls SOA Book http//www.thomaserl.com/boo
  ks.asp
• Ajax In Action http//www.manning.com/crane/
• SOA-J open source project http//soa-j.org