Axis client, omit empty tags from (RPC/encoded style) SOAP request xml

In RPC/encoded style SOAP requests, empty elements are typically omitted from the XML to minimize the payload size. However, not all SOAP libraries or clients automatically handle this optimization. If you're using the Axis client for Java, you might need to implement a custom SOAP handler to achieve this behavior.

To omit empty elements from the SOAP request XML using the Axis client, you can use a SOAP handler to modify the request before it is sent. Here's a general outline of how you can do this:

1. Create a custom SOAP handler that implements the org.apache.axis.Handler interface. This handler will be responsible for manipulating the SOAP request before it is sent.

2. Override the invoke method of the custom handler. This method is called when the SOAP request is being processed.

3. In the invoke method, access the SOAP message's content and remove any empty elements from the XML. You can use DOM manipulation techniques to achieve this.

4. Add your custom handler to the Axis client's handler chain before sending the request.

Here's a simplified example of how your custom SOAP handler might look like:

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import org.apache.axis.AxisFault;
import org.apache.axis.MessageContext;
import org.apache.axis.handlers.BasicHandler;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.NodeList;

public class EmptyTagOmissionHandler extends BasicHandler {

    @Override
    public void invoke(MessageContext msgContext) throws AxisFault {
        try {
            // Access the SOAP message as a DOM Document
            Document doc = msgContext.getEnvelope().getOwnerDocument();
            // Find and remove empty elements
            removeEmptyElements(doc.getDocumentElement());
        } catch (Exception e) {
            throw AxisFault.makeFault(e);
        }
    }

    private void removeEmptyElements(Element element) {
        NodeList childNodes = element.getChildNodes();
        for (int i = childNodes.getLength() - 1; i >= 0; i--) {
            if (childNodes.item(i).getNodeType() == org.w3c.dom.Node.ELEMENT_NODE) {
                Element childElement = (Element) childNodes.item(i);
                // Check if the element is empty (no child elements and no text content)
                if (!childElement.hasChildNodes() && childElement.getTextContent().trim().isEmpty()) {
                    element.removeChild(childElement);
                } else {
                    // Recursively check child elements
                    removeEmptyElements(childElement);
                }
            }
        }
    }
}

To use the custom handler with your Axis client, you need to add it to the client's handler chain before sending the request. Here's an example of how to add the custom handler:

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// Create your Axis client
YourAxisClient client = new YourAxisClient();

// Create an instance of your custom SOAP handler
EmptyTagOmissionHandler customHandler = new EmptyTagOmissionHandler();

// Add the custom handler to the client's handler chain
client.addOption(org.apache.axis.client.Service.REUSE_HANDLER, Boolean.TRUE);
client.addHandler(customHandler);

Make sure to replace YourAxisClient with the appropriate class name for your Axis client.

With this custom SOAP handler, empty elements will be removed from the SOAP request XML before the request is sent, optimizing the payload size for RPC/encoded style SOAP requests.