private boolean isValidTransformation(DataFormat clientFormat, DataFormat serverFormat) {
        return clientFormat != null && serverFormat != null && !clientFormat.equals(serverFormat);
    }
@see io.apiman.gateway.engine.policy.IDataPolicy#getResponseDataHandler(io.apiman.gateway.engine.beans.ApiResponse, io.apiman.gateway.engine.policy.IPolicyContext, java.lang.Object)
plugins/transformation-policy/src/main/java/io/apiman/plugins/transformation_policy/TransformationPolicy.java