public boolean mediate(MessageContext synCtx, int mediatorPosition) {

    boolean returnVal = true;
    int parentsEffectiveTraceState = synCtx.getTracingState();
    // if I have been explicitly asked to enable or disable tracing, set it to the message
    // to pass it on; else, do nothing -> i.e. let the parents state flow
    setEffectiveTraceState(synCtx);
    int myEffectiveTraceState = synCtx.getTracingState();
    try {
      SynapseLog synLog = getLog(synCtx);
      if (synLog.isTraceOrDebugEnabled()) {
        synLog.traceOrDebug("Sequence <" + getType() + "> :: mediate()");
        synLog.traceOrDebug("Mediation started from mediator position : " + mediatorPosition);
      }

      if (contentAware) {
        try {
          if (synLog.isTraceOrDebugEnabled()) {
            synLog.traceOrDebug("Building message. Sequence <" + getType() + "> is content aware");
          }
          RelayUtils.buildMessage(((Axis2MessageContext) synCtx).getAxis2MessageContext(), false);
        } catch (Exception e) {
          handleException("Error while building message", e, synCtx);
        }
      }

      for (int i = mediatorPosition; i < mediators.size(); i++) {
        // ensure correct trace state after each invocation of a mediator
        Mediator mediator = mediators.get(i);
        Integer statisticReportingIndex =
            mediator.reportOpenStatistics(synCtx, i == mediatorPosition);
        synCtx.setTracingState(myEffectiveTraceState);
        if (!mediator.mediate(synCtx)) {
          mediator.reportCloseStatistics(synCtx, statisticReportingIndex);
          returnVal = false;
          break;
        }
        mediator.reportCloseStatistics(synCtx, statisticReportingIndex);
      }
    } catch (SynapseException synEx) {
      throw synEx;
    } catch (Exception ex) {
      String errorMsg = ex.getMessage();
      if (errorMsg == null) {
        errorMsg = "Runtime error occurred while mediating the message";
      }
      handleException(errorMsg, ex, synCtx);
    } finally {
      synCtx.setTracingState(parentsEffectiveTraceState);
    }

    return returnVal;
  }
  /**
   * Handle the response or error (during a failed send) message received for an outgoing request
   *
   * @param messageID Request message ID
   * @param response the Axis2 MessageContext that has been received and has to be handled
   * @param synapseOutMsgCtx the corresponding (outgoing) Synapse MessageContext for the above Axis2
   *     MC, that holds Synapse specific information such as the error handler stack and local
   *     properties etc.
   * @throws AxisFault if the message cannot be processed
   */
  private void handleMessage(
      String messageID,
      MessageContext response,
      org.apache.synapse.MessageContext synapseOutMsgCtx,
      AsyncCallback callback)
      throws AxisFault {
    // apply the tenant information to the out message context
    TenantInfoConfigurator configurator =
        synapseOutMsgCtx.getEnvironment().getTenantInfoConfigurator();
    if (configurator != null) {
      configurator.applyTenantInfo(synapseOutMsgCtx);
    }
    Object o = response.getProperty(SynapseConstants.SENDING_FAULT);
    if (o != null && Boolean.TRUE.equals(o)) {

      StatisticsReporter.reportFaultForAll(
          synapseOutMsgCtx, ErrorLogFactory.createErrorLog(response));
      // there is a sending fault. propagate the fault to fault handlers.

      Stack faultStack = synapseOutMsgCtx.getFaultStack();
      if (faultStack != null && !faultStack.isEmpty()) {

        // if we have access to the full synapseOutMsgCtx.getEnvelope(), then let
        // it flow with the error details. Else, replace its envelope with the
        // fault envelope
        try {
          synapseOutMsgCtx.getEnvelope().build();
        } catch (OMException x) {
          synapseOutMsgCtx.setEnvelope(response.getEnvelope());
        }

        Exception e = (Exception) response.getProperty(SynapseConstants.ERROR_EXCEPTION);

        synapseOutMsgCtx.setProperty(SynapseConstants.SENDING_FAULT, Boolean.TRUE);
        synapseOutMsgCtx.setProperty(
            SynapseConstants.ERROR_CODE, response.getProperty(SynapseConstants.ERROR_CODE));
        synapseOutMsgCtx.setProperty(
            SynapseConstants.ERROR_MESSAGE, response.getProperty(SynapseConstants.ERROR_MESSAGE));
        synapseOutMsgCtx.setProperty(
            SynapseConstants.ERROR_DETAIL, response.getProperty(SynapseConstants.ERROR_DETAIL));
        synapseOutMsgCtx.setProperty(SynapseConstants.ERROR_EXCEPTION, e);

        if (log.isDebugEnabled()) {
          log.debug(
              "[Failed Request Message ID : "
                  + messageID
                  + "]"
                  + " [New to be Retried Request Message ID : "
                  + synapseOutMsgCtx.getMessageID()
                  + "]");
        }

        int errorCode = (Integer) response.getProperty(SynapseConstants.ERROR_CODE);

        // If a timeout has occured and the timeout action of the callback is to discard the message
        if (errorCode == SynapseConstants.NHTTP_CONNECTION_TIMEOUT
            && callback.getTimeOutAction() == SynapseConstants.DISCARD) {
          // Do not execute any fault sequences. Discard message
          if (log.isWarnEnabled()) {
            log.warn(
                "Synapse timed out for the request with Message ID : "
                    + messageID
                    + ". Ignoring fault handlers since the timeout action is DISCARD");
          }
          faultStack.removeAllElements();
        } else {
          ((FaultHandler) faultStack.pop()).handleFault(synapseOutMsgCtx, null);
        }
      }

    } else {

      // there can always be only one instance of an Endpoint in the faultStack of a message
      // if the send was successful, so remove it before we proceed any further
      Stack faultStack = synapseOutMsgCtx.getFaultStack();

      Endpoint successfulEndpoint = null;
      if (faultStack != null && !faultStack.isEmpty() && faultStack.peek() instanceof Endpoint) {
        successfulEndpoint = (Endpoint) faultStack.pop();
      }

      if (log.isDebugEnabled()) {
        log.debug("Synapse received an asynchronous response message");
        log.debug(
            "Received To: " + (response.getTo() != null ? response.getTo().getAddress() : "null"));
        log.debug(
            "SOAPAction: "
                + (response.getSoapAction() != null ? response.getSoapAction() : "null"));
        log.debug(
            "WSA-Action: " + (response.getWSAAction() != null ? response.getWSAAction() : "null"));
        String[] cids = response.getAttachmentMap().getAllContentIDs();
        if (cids != null && cids.length > 0) {
          for (String cid : cids) {
            log.debug("Attachment : " + cid);
          }
        }
        log.debug("Body : \n" + response.getEnvelope());
      }
      MessageContext axisOutMsgCtx =
          ((Axis2MessageContext) synapseOutMsgCtx).getAxis2MessageContext();

      // Processes 'Accept-Encoding'
      ResponseAcceptEncodingProcessor.process(response, axisOutMsgCtx);

      response.setServiceContext(null);
      response.setOperationContext(axisOutMsgCtx.getOperationContext());
      response.setAxisMessage(
          axisOutMsgCtx.getAxisOperation().getMessage(WSDLConstants.MESSAGE_LABEL_OUT_VALUE));

      // set properties on response
      response.setServerSide(true);
      response.setProperty(SynapseConstants.ISRESPONSE_PROPERTY, Boolean.TRUE);
      response.setProperty(
          MessageContext.TRANSPORT_OUT, axisOutMsgCtx.getProperty(MessageContext.TRANSPORT_OUT));
      response.setProperty(
          org.apache.axis2.Constants.OUT_TRANSPORT_INFO,
          axisOutMsgCtx.getProperty(org.apache.axis2.Constants.OUT_TRANSPORT_INFO));
      response.setTransportIn(axisOutMsgCtx.getTransportIn());
      response.setTransportOut(axisOutMsgCtx.getTransportOut());

      // If request is REST assume that the response is REST too
      response.setDoingREST(axisOutMsgCtx.isDoingREST());
      if (axisOutMsgCtx.isDoingMTOM()) {
        response.setDoingMTOM(true);
        response.setProperty(
            org.apache.axis2.Constants.Configuration.ENABLE_MTOM,
            org.apache.axis2.Constants.VALUE_TRUE);
      }
      if (axisOutMsgCtx.isDoingSwA()) {
        response.setDoingSwA(true);
        response.setProperty(
            org.apache.axis2.Constants.Configuration.ENABLE_SWA,
            org.apache.axis2.Constants.VALUE_TRUE);
      }

      // when axis2 receives a soap message without addressing headers it users
      // DISABLE_ADDRESSING_FOR_OUT_MESSAGES property to keep it and hence avoid addressing
      // headers on the response. this causes a problem for synapse if the original message
      // it receivs (from client) has addressing and the synaspse service invocation has not
      // engage addressing. in this case when synapse receives the response from the server
      // addessing In handler dissable addressing since that response does not have addressing
      // headers. synapse sends the response to its orignal client using the same message
      // context. Then this response does not have addressing headers since it already
      // disable. to avoid this we need to set the DISABLE_ADDRESSING_FOR_OUT_MESSAGES
      // property state to original state.
      if (axisOutMsgCtx.getProperty(AddressingConstants.DISABLE_ADDRESSING_FOR_OUT_MESSAGES)
          != null) {

        response.setProperty(
            AddressingConstants.DISABLE_ADDRESSING_FOR_OUT_MESSAGES,
            axisOutMsgCtx.getProperty(AddressingConstants.DISABLE_ADDRESSING_FOR_OUT_MESSAGES));
      } else {
        response.removeProperty(AddressingConstants.DISABLE_ADDRESSING_FOR_OUT_MESSAGES);
      }

      Object messageType =
          axisOutMsgCtx.getProperty(org.apache.axis2.Constants.Configuration.MESSAGE_TYPE);
      if (!HTTPConstants.MEDIA_TYPE_X_WWW_FORM.equals(messageType)) {
        // copy the message type property that's used by the out message to the
        // response message
        response.setProperty(org.apache.axis2.Constants.Configuration.MESSAGE_TYPE, messageType);
      }

      // compare original received message (axisOutMsgCtx) soap version with the response
      // if they are different change to original version
      if (axisOutMsgCtx.isSOAP11() != response.isSOAP11()) {
        if (axisOutMsgCtx.isSOAP11()) {
          SOAPUtils.convertSOAP12toSOAP11(response);
        } else {
          SOAPUtils.convertSOAP11toSOAP12(response);
        }
      }

      if (axisOutMsgCtx.getMessageID() != null) {
        response.setRelationships(new RelatesTo[] {new RelatesTo(axisOutMsgCtx.getMessageID())});
      }

      response.setReplyTo(axisOutMsgCtx.getReplyTo());
      response.setFaultTo(axisOutMsgCtx.getFaultTo());

      if (axisOutMsgCtx.isPropertyTrue(NhttpConstants.IGNORE_SC_ACCEPTED)) {
        response.setProperty(NhttpConstants.FORCE_SC_ACCEPTED, Constants.VALUE_TRUE);
      }

      // create the synapse message context for the response
      Axis2MessageContext synapseInMessageContext =
          new Axis2MessageContext(
              response, synapseOutMsgCtx.getConfiguration(), synapseOutMsgCtx.getEnvironment());
      synapseInMessageContext.setResponse(true);

      Object obj = synapseOutMsgCtx.getProperty(SynapseConstants.FORCE_ERROR_PROPERTY);
      String errorOnSOAPFault = (String) obj;

      if (Constants.VALUE_TRUE.equals(errorOnSOAPFault) && successfulEndpoint != null) {

        if (log.isDebugEnabled()) {
          log.debug("FORCE_ERROR_ON_SOAP_FAULT is true, checking for SOAPFault");
        }

        try {
          RelayUtils.buildMessage(
              ((Axis2MessageContext) synapseInMessageContext).getAxis2MessageContext(), true);
        } catch (Exception e) {
          // handleException("Error while building message", e, synapseInMessageContext);
        }

        if ((synapseInMessageContext.getEnvelope() != null)
            && synapseInMessageContext.getEnvelope().hasFault()) {

          if (log.isDebugEnabled()) {
            log.debug(
                "SOAPFault found in response message, forcing endpoint "
                    + successfulEndpoint.getName()
                    + " to fail");
          }

          // setup new pipe configuration..if failure happens (this will be setup as the source
          // writer and during the TargetContext
          // clean up operation the writer will be reset and pull to the buffer
          MessageContext axis2OUTMC =
              ((Axis2MessageContext) synapseOutMsgCtx).getAxis2MessageContext();
          NHttpServerConnection conn =
              (NHttpServerConnection) axis2OUTMC.getProperty("pass-through.Source-Connection");
          if (conn != null) {
            SourceConfiguration sourceConfiguration =
                (SourceConfiguration) axis2OUTMC.getProperty("PASS_THROUGH_SOURCE_CONFIGURATION");
            Pipe pipe =
                new Pipe(
                    conn,
                    sourceConfiguration.getBufferFactory().getBuffer(),
                    "source",
                    sourceConfiguration);
            axis2OUTMC.setProperty(PassThroughConstants.PASS_THROUGH_PIPE, pipe);
          }

          StatisticsReporter.reportFaultForAll(
              synapseOutMsgCtx, ErrorLogFactory.createErrorLog(response));
          synapseOutMsgCtx.setProperty(SynapseConstants.SENDING_FAULT, Boolean.TRUE);
          synapseOutMsgCtx.setProperty(
              SynapseConstants.ERROR_CODE, SynapseConstants.ENDPOINT_CUSTOM_ERROR);
          ((FaultHandler) successfulEndpoint).handleFault(synapseOutMsgCtx, null);
          return;
        } else {
          successfulEndpoint.onSuccess();
        }

      } else if (successfulEndpoint != null) {
        successfulEndpoint.onSuccess();
      }

      synapseInMessageContext.setTo(
          new EndpointReference(AddressingConstants.Final.WSA_ANONYMOUS_URL));
      synapseInMessageContext.setTracingState(synapseOutMsgCtx.getTracingState());

      // set the properties of the original MC to the new MC

      for (Object key : synapseOutMsgCtx.getPropertyKeySet()) {
        synapseInMessageContext.setProperty(
            (String) key, synapseOutMsgCtx.getProperty((String) key));
      }

      // Copy SequenceCallStack from original MC to the new MC
      if (synapseOutMsgCtx.isContinuationEnabled()) {

        // Set the message direction
        if (!synapseOutMsgCtx.isResponse()) {
          synapseInMessageContext.setResponse(false);
        }

        Stack<ContinuationState> seqContinuationStates =
            synapseOutMsgCtx.getContinuationStateStack();
        for (int i = 0; i < seqContinuationStates.size(); i++) {
          synapseInMessageContext.pushContinuationState(seqContinuationStates.get(i));
        }
      }

      // If this response is related to session affinity endpoints -Server initiated session
      Dispatcher dispatcher =
          (Dispatcher)
              synapseOutMsgCtx.getProperty(SynapseConstants.PROP_SAL_ENDPOINT_CURRENT_DISPATCHER);
      if (dispatcher != null && dispatcher.isServerInitiatedSession()) {
        dispatcher.updateSession(synapseInMessageContext);
      }

      StatisticsReporter.reportForAllOnResponseReceived(synapseInMessageContext);

      // send the response message through the synapse mediation flow
      try {
        synapseOutMsgCtx.getEnvironment().injectMessage(synapseInMessageContext);
      } catch (SynapseException syne) {
        Stack stack = synapseInMessageContext.getFaultStack();
        if (stack != null && !stack.isEmpty()) {
          ((FaultHandler) stack.pop()).handleFault(synapseInMessageContext, syne);
        } else {
          log.error(
              "Synapse encountered an exception, "
                  + "No error handlers found - [Message Dropped]\n"
                  + syne.getMessage());
        }
      }
    }
  }
  public void send(MessageContext synCtx) {

    logSetter();

    Integer statisticReportingIndex = null;
    boolean isStatisticsEnabled = RuntimeStatisticCollector.isStatisticsEnabled();
    if (isStatisticsEnabled) {
      statisticReportingIndex =
          OpenEventCollector.reportEntryEvent(
              synCtx,
              getReportingName(),
              definition.getAspectConfiguration(),
              ComponentType.ENDPOINT);
    }

    boolean traceOn = isTraceOn(synCtx);
    boolean traceOrDebugOn = isTraceOrDebugOn(traceOn);

    if (!initialized) {
      // can't send to a non-initialized endpoint. This is a program fault
      throw new IllegalStateException(
          "not initialized, " + "endpoint must be in initialized state");
    }

    prepareForEndpointStatistics(synCtx);

    if (traceOrDebugOn) {
      String address = definition.getAddress();
      if (address == null && synCtx.getTo() != null && synCtx.getTo().getAddress() != null) {
        // compute address for the default endpoint only for logging purposes
        address = synCtx.getTo().getAddress();
      }

      traceOrDebug(
          traceOn,
          "Sending message through endpoint : " + getName() + " resolving to address = " + address);
      traceOrDebug(
          traceOn,
          "SOAPAction: " + (synCtx.getSoapAction() != null ? synCtx.getSoapAction() : "null"));
      traceOrDebug(
          traceOn,
          "WSA-Action: " + (synCtx.getWSAAction() != null ? synCtx.getWSAAction() : "null"));
      if (traceOn && trace.isTraceEnabled()) {
        trace.trace("Envelope : \n" + synCtx.getEnvelope());
      }
    }

    // push the errorHandler sequence into the current message as the fault handler
    if (errorHandler != null) {
      Mediator errorHandlerMediator = synCtx.getSequence(errorHandler);
      if (errorHandlerMediator != null) {
        if (traceOrDebugOn) {
          traceOrDebug(
              traceOn,
              "Setting the onError handler : "
                  + errorHandler
                  + " for the endpoint : "
                  + endpointName);
        }
        synCtx.pushFaultHandler(new MediatorFaultHandler(errorHandlerMediator));
      } else {
        log.warn(
            "onError handler sequence : "
                + errorHandler
                + " for : "
                + endpointName
                + " cannot be found");
      }
    }

    // register this as the immediate fault handler for this message.
    synCtx.pushFaultHandler(this);
    // add this as the last endpoint to process this message - used by statistics counting code
    synCtx.setProperty(SynapseConstants.LAST_ENDPOINT, this);
    // set message level metrics collector
    org.apache.axis2.context.MessageContext axis2Ctx =
        ((Axis2MessageContext) synCtx).getAxis2MessageContext();
    axis2Ctx.setProperty(BaseConstants.METRICS_COLLECTOR, metricsMBean);

    if (contentAware) {
      try {
        RelayUtils.buildMessage(((Axis2MessageContext) synCtx).getAxis2MessageContext(), false);
        axis2Ctx.setProperty(RelayConstants.FORCE_RESPONSE_EARLY_BUILD, Boolean.TRUE);
        if (forceBuildMC) {
          ((Axis2MessageContext) synCtx).getAxis2MessageContext().getEnvelope().build();
        }
      } catch (Exception e) {
        handleException("Error while building message", e);
      }
    }

    evaluateProperties(synCtx);

    // if the envelope preserving set build the envelope
    MediatorProperty preserveEnv = getProperty(SynapseConstants.PRESERVE_ENVELOPE);
    if (preserveEnv != null
        && JavaUtils.isTrueExplicitly(
            preserveEnv.getValue() != null
                ? preserveEnv.getValue()
                : preserveEnv.getEvaluatedExpression(synCtx))) {
      if (traceOrDebugOn) {
        traceOrDebug(
            traceOn,
            "Preserving the envelope by building it before "
                + "sending, since it is explicitly set");
      }
      synCtx.getEnvelope().build();
    }

    // Send the message through this endpoint
    synCtx.getEnvironment().send(definition, synCtx);

    if (isStatisticsEnabled) {
      CloseEventCollector.closeEntryEvent(
          synCtx, getReportingName(), ComponentType.ENDPOINT, statisticReportingIndex, false);
    }
  }