Weblog for the AMIS Technology corner
Posts tagged java callout
The Oracle SOA Suite 11g HttpBinding or another way to call RESTful services from SOA Composite Applications
Dec 15th
I wanted to take a quick look at REST(ful) WebServices and see how those can be integrated into the SCA based SOA Composite Applications that we create with the Oracle SOA Suite. Currently, it does not have the HTTP binding that the 10.1.3 release of the SOA Suite used to have. So what are the alternatives?
In this article, I want to demonstrate a way of calling RESTful (simple http request based) services into a SOA Composite application. I show one way of doing so using the Google Translation Service, a RESTful service described at http://code.google.com/apis/ajaxlanguage/documentation/ and to be accessed at http://ajax.googleapis.com/ajax/services/language/translate?v=1.0&q=hello%20world&langpair=en%7Cit. This service takes a string to translate and an indication of a source and a destination language. Though maybe not formally resource oriented enough to be called REST-style (or RESTful) service by some, it is a service that does not require SOAP or WS* but simply a HTTP Get request. So at least quite restful.
In this article I will use the work I did and described in the previous article: Leveraging RESTful Services from Java application using Jersey (Introduction). Using project Jersey's support for clients of RESTful services and the JSON-SIMPLE library to interpret the response I get from the GoogleTranslation service, I will hook up with the RESTful Service. Then I will leverage the Mediator Java Callout mechanism to integrate this REST-service-client into a SOA Composite application. The Mediator I create will be the fully SOA Suite integrated front-end of this RESTful Service.
SOA Suite 11g – introducing Mediator Java Callouts for debug, audit and …
Dec 13th
The Mediator component in SOA Suite 11g has a the option to specify a Java Callout, one for every WSDL operation. The Java Callout refers to a Java Class, either on the SOA Suite's classpath or deployed as part of the SOA Composite application. This class should implement interface oracle.tip.mediator.common.api.IJavaCallout and a convenient way of doing so is by extending AbstractJavaCalloutImpl in package oracle.tip.mediator.common.api.
The Java Callout is invoked by the Mediator on a number of times, prior to and after performing the Routing Rule and each of the cases in it. The Java Callout class can implement a number of methods, one for each specific event or stage in the Mediator process. These methods get access to the input message as well as the transformation result. That means that the callout class can inspect, validate, log, audit and even manipulate these messages, their payloads, headers and properties. Interestingly enough, the methods are not static what I thought might be the case. The first one to be called is an initialize() that has you initialize the callout class instance to prepare the object for further callout processing. This means that all stages in a single Mediation action are processed by the same callout object. This allows you to compare for example the pre and post transformation values.
The methods that the callout interface specifies are: initialize, preRouting (before any routing rule cases are processed), preRoutingRule (before one specific routing rule is processed), preCallbackRouting (This method is called before Mediator finishes executing callback handling. You can customize this method to perform callback auditing and custom fault tracking.) , postCallbackRouting, postRoutingRule, postRouting.
This article shows a simple example of creating a SOA Composite Application – the simplest one you can create I believe using the new 11g feature of Echo – with use of the Java Callout class.
