Sunday, August 4, 2013

Writing a simple Axis2 handler

If we want to listen all the incoming/outgoing messages coming to/from the service, we can write an axis2 handler which can be placed in a phase, which is executed in order as defined in the axis2 configuration. The phase can contain more than one handler.
Message flow is categorized  as;

  • InFlow
  • OutFlow
  • InFaultFlow
  • OutFaultFlow
As name implies, the message flows indicate the request,response and their fault execution paths. In each flow there are phases defined and we can keep our handler in the right flow and right phase.

Sample code:

package org.test.sample;

import org.apache.axis2.handlers.AbstractHandler;
import org.apache.axis2.description.AxisService;
import org.apache.axis2.context.MessageContext;


public class MessageHandler extends AbstractHandler {
private static final Log log = LogFactory.getLog(MessageHandler.class);

@Override
public InvocationResponse invoke(MessageContext msgcontext) throws AxisFault {
if (log.isDebugEnabled()) {
log.debug("Message Store handler is executing");
}
AxisService axService = msgcontext.getAxisService();
//TODO
return InvocationResponse.CONTINUE;
}


The message execution can be continued, aborted or suspended.

Once we created the jar out of this, we need to keep the jar in the classpath(ie:lib folder) and has to register the handler in the axis2 configuration.
We can register the handler programmatically as a module or  we can edit the axis2.xml file based on the requirement.

Editing axis2.xml

Add the following configuration in the suitable flow/phase.
< phaseOrder type="InFlow">
< phase name="Transport">
< handler name="MessageHandler" class="org.test.sample.MessageHandler">
......
< /phaseOrder>

Programmatically adding the module;

axis2Service.engageModule(axisCfg.getModule(testModule));

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