Sending the Request

This section covers the code for creating and sending the request for an updated price list. This is done in the getPriceList method of PriceListRequest, which follows the DTD price-list.dtd.

The getPriceList method begins by creating the connection that will be used to send the request. Then it gets the default MessageFactory object to be used for creating the SOAPMessage object msg.

SOAPConnectionFactory scf = SOAPConnectionFactory.newInstance();
SOAPConnection con = scf.createConnection();
SOAPFactory soapFactory = SOAPFactory.newInstance();

MessageFactory mf = MessageFactory.newInstance();
SOAPMessage msg = mf.createMessage();

The next step is to access the message’s SOAPBody object, to which the message’s content will be added.

SOAPBody body = msg.getSOAPBody();

The file price-list.dtd specifies that the topmost element inside the body is request-prices and that it contains the element request. The text node added to request is the text of the request being sent. Every new element that is added to the message must have a QName object to identify it. The following lines of code create the top-level element in the SOAPBody object body. The first element created in a SOAPBody object is always a SOAPBodyElement object.

Name bodyName = new QName("http://sonata.coffeebreak.com",
    "request-prices", "RequestPrices");
SOAPBodyElement requestPrices =
    body.addBodyElement(bodyName);

In the next few lines, the code adds the element request to the element request-prices (represented by the SOAPBodyElement requestPrices). Then the code adds a text node containing the text of the request. Next, because there are no other elements in the request, the code calls the method saveChanges on the message to save what has been done.

QName requestName = new QName("request");
SOAPElement request = requestPrices.addChildElement(requestName);
request.addTextNode("Send updated price list.");

msg.saveChanges();

With the creation of the request message completed, the code sends the message to the SAAJ coffee supplier. The message being sent is the SOAPMessage object msg, to which the elements created in the previous code snippets were added. The endpoint is the URI for the SAAJ coffee supplier, http://localhost:8080/saaj-coffee-supplier/getPriceList. The SOAPConnection object con is used to send the message, and because it is no longer needed, it is closed.

URL endpoint = new URL(url);
SOAPMessage response = con.call(msg, endpoint);
con.close();

When the call method is executed, the Application Server executes the servlet PriceListServlet. This servlet creates and returns a SOAPMessage object whose content is the SAAJ supplier’s price list. (PriceListServlet is discussed in Returning the Price List.) The Application Server knows to execute PriceListServlet because the given endpoint is mapped to that servlet.

Extracting the Price List

This section demonstrates (1) retrieving the price list that is contained in response, the SOAPMessage object returned by the method call, and (2) returning the price list as a PriceListBean.

The code creates an empty Vector object that will hold the coffee-name and price elements that are extracted from response. Then the code uses response to access its SOAPBody object, which holds the message’s content.

Vector<String> list = new Vector<String>();

SOAPBody responseBody = response.getSOAPBody();

The next step is to retrieve the SOAPBodyElement object. The method getChildElements returns an Iterator object that contains all the child elements of the element on which it is called, so in the following lines of code, it1 contains the SOAPBodyElement object bodyEl, which represents the price-list element.

Iterator it1 = responseBody.getChildElements();
 while (it1.hasNext()) {
     SOAPBodyElement bodyEl = (SOAPBodyElement)it1.next();

The Iterator object it2 holds the child elements of bodyEl, which represent coffee elements. Calling the method next on it2 retrieves the first coffee element in bodyEl. As long as it2 has another element, the method next will return the next coffee element.

    Iterator it2 = bodyEl.getChildElements();
    while (it2.hasNext()) {
        SOAPElement child2 = (SOAPElement)it2.next();

The next lines of code drill down another level to retrieve the coffee-name and price elements contained in it3. Then the message getValue retrieves the text (a coffee name or a price) that the SAAJ coffee supplier added to the coffee-name and price elements when it gave content to response. The final line in the following code fragment adds the coffee name or price to the Vector object list. Note that because of the nested while loops, for each coffee element that the code retrieves, both of its child elements (the coffee-name and price elements) are retrieved.

        Iterator it3 = child2.getChildElements();
        while (it3.hasNext()) {
            SOAPElement child3 = (SOAPElement)it3.next();
            String value = child3.getValue();
            list.addElement(value);
        }
    }
}

The final code fragment adds the coffee names and their prices (as a PriceListItem) to the ArrayList priceItems, and prints each pair on a separate line. Finally it constructs and returns a PriceListBean.

ArrayList<PriceItemBean> items = new ArrayList<PriceItemBean>();
for (int i = 0; i < list.size(); i = i + 2) {
    PriceItemBean pib = new PriceItemBean();
    pib.setCoffeeName(list.elementAt(i).toString());
    pib.setPricePerPound(new BigDecimal(list.elementAt(i + 1).toString()));
    items.add(pib);
    System.out.print(list.elementAt(i) + "        ");
    System.out.println(list.elementAt(i + 1));
}

Date today = new Date();
Date endDate = DateHelper.addDays(today, 30);
GregorianCalendar todayCal = new GregorianCalendar();
todayCal.setTime(today);
GregorianCalendar cal = new GregorianCalendar();
cal.setTime(endDate);
plb = new PriceListBean();
plb.setStartDate(DatatypeFactory.newInstance().newXMLGregorianCalendar(todayCal));

List<PriceItemBean> priceItems = new ArrayList<PriceItemBean>();
Iterator<PriceItemBean> i = items.iterator();
while (i.hasNext()) {
    PriceItemBean pib = i.next();
    plb.getPriceItems().add(pib);
}

plb.setEndDate(DatatypeFactory.newInstance().newXMLGregorianCalendar(cal));