Removing additional namespace prefixes in the SOAP Fault using a Class Mediator

In the previous post I have described how to use an xslt mediator to remove unwanted namespace prefixes in the SOAP Fault. This blog post describes how to accomplish that task using a simple Class Mediator.

You can fine more information about how to implement a class mediator at [1].

Sample implementation of the Class Mediator is as follows

package org.wso2.sample.mediator;

import java.util.Iterator;
import javax.xml.namespace.QName;
import org.apache.axiom.om.OMAbstractFactory;
import org.apache.axiom.om.OMAttribute;
import org.apache.axiom.om.OMElement;
import org.apache.axiom.om.OMFactory;
import org.apache.axiom.om.OMNamespace;
import org.apache.axiom.om.OMNode;
import org.apache.axiom.om.OMText;
import org.apache.axiom.soap.SOAPBody;
import org.apache.axiom.soap.SOAPFault;
import org.apache.synapse.MessageContext;
import org.apache.synapse.mediators.AbstractMediator;

/**
 * 
 * This class removes the additional axis2 namespace prefixes and creates a new
 * OMElement
 * 
 */
public class Axis2NSPrefixRemoveMediator extends AbstractMediator {

 private static final String AXIS2_NAMESPACE_PREFIX = "axis2ns";
 private static final String CLONED_ROOT = "ClonedDetail";

 public boolean mediate(MessageContext synCtx) {
 
        SOAPBody soapBody = synCtx.getEnvelope().getBody();
  
           //Check for a Fault
 if(soapBody.hasFault()){
  SOAPFault  faultNode = soapBody.getFault();
   
    // Retrieves the Detail Element
 OMElement detailNode = faultNode.getDetail();
   
 if (detailNode.getChildElements().hasNext()) {

 Iterator<?> complexElement = detailNode.getChildElements();
 OMFactory fac = OMAbstractFactory.getOMFactory();
    
 // Creates a clone from detail element
 OMElement clonedRoot = fac.createOMElement(new QName(CLONED_ROOT));
    
 //For every child creates a cloned element without axis2ns prefix
 getChildrenRecursively(fac, clonedRoot, complexElement);

  if (clonedRoot.getChildElements().hasNext()) {
     
  // Detach the fault body
  Iterator<?> children = detailNode.getChildElements();
  while (children.hasNext()) {
   ((OMNode) children.next()).detach();
    }
     
  // Attach the new fault body
  Iterator<?> clonedChildren = clonedRoot.getChildElements();
  while (clonedChildren.hasNext()) {
   detailNode.addChild((OMElement) clonedChildren.next());
    }
   }
      }
  }
 
  return true;
 }

 /**
  * 
  * @param fac OMFactory
  * @param root root element of the detail block
  * @param complexElement children of the detail block
  * @return final list of elements
  */
private OMElement getChildrenRecursively(OMFactory fac, OMElement root, Iterator<?> complexElement) {

 while (complexElement.hasNext()) {

 Object next = complexElement.next();
 if  (next instanceof OMElement) {
   
 OMElement element = (OMElement) next; 
 // Creates the new OMElement excluding additional namespace prefixes
 OMElement duplicateElement = createNewOMElement(fac, element);
 
 if (element.getChildElements().hasNext()) {
getChildrenRecursively(fac, duplicateElement, element.getChildElements());
     
 //Add to root at the end of populating the child
 root.addChild(duplicateElement);
 } else {
 // If no more children add it to root
  root.addChild(duplicateElement);
  }
      }
          }

  return root;
 }

 /**
  * 
  * @param fac OMFactory
  * @param element complex element
  * @return duplicated new OMElement
  */
 private OMElement createNewOMElement(OMFactory fac, OMElement element) {

  OMElement duplicateElement = null;
  String elementText = element.getText();

  // Set Namespace
  duplicateElement = setNameSpaces(fac, element);
  // Set Attributes
  setAttributes(element, duplicateElement);
  // Set text
  setTextValues(fac, duplicateElement, elementText);

  return duplicateElement;

 }

 /**
  * 
  * @param fac OMFactory
  * @param rootElement newly created OMElement
  * @param elementText Text of the element
  */
 private void setTextValues(OMFactory fac, OMElement rootElement, String elementText) {
  // Includes the text as a child
  if (elementText != null && !elementText.isEmpty()) {
   OMText omText = fac.createOMText(elementText);
   rootElement.addChild(omText);
  }
 }

 /**
  * 
  * @param element complex element
  * @param tempElement newly created OMElement
  */
 private void setAttributes(OMElement element, OMElement tempElement) {
  // Get the attributes
  Iterator<?> allAttributes = element.getAllAttributes();

  while (allAttributes.hasNext()) {
  tempElement.addAttribute((OMAttribute) allAttributes.next());
  }
 }

 /**
  * 
  * @param fac OMFactory
  * @param tempElement newly created OMElement
  * @return OMElement without axis2 namespace prefix
  */
 private OMElement setNameSpaces(OMFactory fac, OMElement tempElement) {

  String name = tempElement.getLocalName();
  OMNamespace namespace = tempElement.getNamespace();

  if (name != null && namespace != null) {

  String namespaceURI = namespace.getNamespaceURI();
  String namespacePrefix = namespace.getPrefix();
  if (namespacePrefix.startsWith(AXIS2_NAMESPACE_PREFIX)) {
  // Removes additional namespaces  

String emptyNamespacePrefix = namespace.getPrefix().replace(namespacePrefix, "");
OMNamespace modifiedNamespace = fac.createOMNamespace(namespaceURI, emptyNamespacePrefix);
 // Creates the final OMElement with correct namesapce
  tempElement = fac.createOMElement(name, modifiedNamespace);
   }
  }else{
   tempElement = fac.createOMElement(name, namespace);
  }
  return tempElement;
 }

}

Please refer [2] for more information about configuring the class mediator in synapse configuration

[1] http://soasecurity.org/2013/11/28/how-to-wso2esb-how-to-write-custom-mediator/

[2]  https://docs.wso2.com/display/ESB481/Class+Mediator