The class mediator creates an instance of a custom specified class and sets it as a mediator. The class must implement the org.apache.synapse.api.Mediator interface. If any properties are specified, the corresponding setter methods are invoked on the class, once, during initialization.
<class name="class-name"> <property name="string" value="literal"> (either literal or XML child) </property> </class>
Figure 1: Adding a class mediator
Clicking on the class mediator created as shown in figure 1 will open up the class mediator specific options. You can specify the class mediator implementaion class and load it by clicking LoadClass button. Once you load the class you'll see the class mediator configuration options as in figure2.
Figure 2: Class mediator configuration options
Class mediator configuration descriptions
<definitions xmlns="http://ws.apache.org/ns/synapse"> <sequence name="fault"> <makefault> <code value="tns:Receiver" xmlns:tns="http://www.w3.org/2003/05/soap-envelope"/> <reason value="Mediation failed."/> </makefault> <send/> </sequence> <sequence name="main" onError="fault"> <in> <send> <endpoint name="stockquote"> <address uri="http://localhost:9000/services/SimpleStockQuoteService"/> </endpoint> </send> </in> <out> <class name="samples.mediators.SimpleClassMediator"> <property name="varible1" value="10"/> <property name="varible2" value="5"/> </class> <send/> </out> </sequence> </definitions>
In this configuration, ESB hands over the request message to the specified endpoint, which sends it to the Axis2 server running on port 9000. But the response message is passed through the class mediator before sending it back to the client. Two parameters named "varible1" and "varible2" are passed to the instance mediator implementation class(SimpleClassMediator). Look at the following sample class mediator. Note how the SynapseMessageContext and to the full Synapse API in there.
A simple class mediator implementaion.
package samples.mediators; import org.apache.synapse.MessageContext; import org.apache.synapse.Mediator; import org.apache.axiom.om.OMElement; import org.apache.axiom.om.OMAbstractFactory; import org.apache.axiom.om.OMFactory; import org.apache.axiom.soap.SOAPFactory; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import javax.xml.namespace.QName; public class SimpleClassMediator implements Mediator { private static final Log log = LogFactory.getLog(DiscountQuoteMediator.class); private String varible1="10"; private String varible2="10"; private int varible3=0; public DiscountQuoteMediator(){} public boolean mediate(MessageContext mc) { // Do somthing useful.. // Note the access to the Synapse Message context return true; } public String getType() { return null; } public void setTraceState(int traceState) { traceState = 0; } public int getTraceState() { return 0; } public void setvarible1(String newValue) { varible1=newValue; } public String getvarible1() { return varible1; } public void setvarible2(String newValue){ varible2=newValue; } public String getvarible2(){ return varible2; } }
A fully working sample is availble. See synapase configuration lanaguge guide for detailed(under section called class mediator) working sample.