Channels ▼
RSS

Design

Service-Component Architectures

Source Code Accompanies This Article. Download It Now.


Wiring

Component connectivity is handled through "Wiring," which implies defining source/target information between Components. As with other SCA elements, the details of Wiring can be set declaratively. SCA Wiring does not require the source and targets to be of the same type (Java interfaces to WSDL is acceptable, for instance) as long as compatibility concerns such as remoteability, callback support, Fault, and Exception handling are addressed. Example 3(a) is a simple wiring example.

<composite xmlns="http://www.osoa.org/xmlns/sca/1.0"
           name="CalculatorComposite">
    <service name="CalculatorService">
        <interface.java interface="calculator.CalculatorService"/>
        <reference>CalculatorServiceComponent</reference>
    </service>
    <component name="CalculatorServiceComponent">
      <implementation.java class="calculator.CalculatorServiceImpl"/>
      <reference name="addService">AddServiceComponent</reference>
      ...
    </component>
    <component name="AddServiceComponent">
        <implementation.java class="calculator.AddServiceImpl"/>
    </component>
    ...
</composite>

Example 2: Reference declaration.

(a)
<reference name="stockQuoteService"
target="StockQuoteMediatorComponent"/>

(b)
    <reference name="HelloWorldService"> 
      <interface.java interface="helloworld.HelloWorldService"
         callbackInterface="helloworld.HelloWorldCallback"/>
<interface.wsdl xmlns:wsdli="http://www.w3.org/2006/01/wsdl-instance" interface="http://helloworld#wsdl.interface(HelloWorld)" 
callbackInterface="http://helloworld#wsdl.interface(HelloWorldCallback)"
      wsdli:wsdlLocation="http://helloworld wsdl/helloworld.wsdl" />
      <binding.ws endpoint=
"http://helloworld#wsdl.endpoint(HelloWorldService/HelloWorldSoapPort)" location="wsdl/helloworld.wsdl" />
    </reference>

Example 3: (a) Explicit wiring in a reference; (b) reference bound to a web service.

To simplify development, SCA supports "Autowiring." As long as References are unambiguous, the container should be capable of wiring components at runtime.


Related Reading


More Insights






Currently we allow the following HTML tags in comments:

Single tags

These tags can be used alone and don't need an ending tag.

<br> Defines a single line break

<hr> Defines a horizontal line

Matching tags

These require an ending tag - e.g. <i>italic text</i>

<a> Defines an anchor

<b> Defines bold text

<big> Defines big text

<blockquote> Defines a long quotation

<caption> Defines a table caption

<cite> Defines a citation

<code> Defines computer code text

<em> Defines emphasized text

<fieldset> Defines a border around elements in a form

<h1> This is heading 1

<h2> This is heading 2

<h3> This is heading 3

<h4> This is heading 4

<h5> This is heading 5

<h6> This is heading 6

<i> Defines italic text

<p> Defines a paragraph

<pre> Defines preformatted text

<q> Defines a short quotation

<samp> Defines sample computer code text

<small> Defines small text

<span> Defines a section in a document

<s> Defines strikethrough text

<strike> Defines strikethrough text

<strong> Defines strong text

<sub> Defines subscripted text

<sup> Defines superscripted text

<u> Defines underlined text

Dr. Dobb's encourages readers to engage in spirited, healthy debate, including taking us to task. However, Dr. Dobb's moderates all comments posted to our site, and reserves the right to modify or remove any content that it determines to be derogatory, offensive, inflammatory, vulgar, irrelevant/off-topic, racist or obvious marketing or spam. Dr. Dobb's further reserves the right to disable the profile of any commenter participating in said activities.

 
Disqus Tips To upload an avatar photo, first complete your Disqus profile. | View the list of supported HTML tags you can use to style comments. | Please read our commenting policy.
 

Video