Home > Articles > Programming > Java

  • Print
  • + Share This
This chapter is from the book

This chapter is from the book

JAXM

The Java API for XML Messaging (page 265) (JAXM) provides a standard way to send XML documents over the Internet from the Java platform. It is based on the SOAP 1.1 and SOAP with Attachments specifications and can be extended to work with higher level messaging protocols such as ebXML Transport, Routing, and Packaging that are built on top of SOAP.

Typically, a business uses a messaging provider service, which does the behind-the-scenes work required to transport and route messages. When a messaging provider is used, all JAXM messages go through it, so when a business sends a message, the message first goes to the sender's messaging provider, then to the recipient's messaging provider, and finally to the intended recipient. It is also possible to route a message to go to intermediate recipients before it goes to the ultimate destination.

Because messages go through it, a messaging provider can take care of housekeeping details like assigning message identifiers, storing messages, and keeping track of whether a message has been delivered before. A messaging provider can also try resending a message that did not reach its destination on the first attempt at delivery. The beauty of a messaging provider is that the client using JAXM technology (JAXM client) is totally unaware of what the provider is doing in the background. The JAXM client simply makes Java method calls, and the messaging provider in conjunction with the messaging infrastructure makes everything happen behind the scenes.

Though in the typical scenario a business uses a messaging provider, it is also possible to do JAXM messaging without using a messaging provider. In this case, the JAXM client (called a standalone client) is limited to sending point-to-point messages directly to a Web service that is implemented for request-response messaging. Request-response messaging is synchronous, meaning that a request is sent and its response is received in the same operation. A request-response message is sent over a SOAPConnection object via the method SOAPConnection.call, which sends the message and blocks until it receives a response. A standalone client can operate only in a client role, that is, it can only send requests and receive their responses. In contrast, a JAXM client that uses a messaging provider may act in either the client or server (service) role. In the client role, it can send requests; in the server role, it can receive requests, process them, and send responses.

Though it is not required, JAXM messaging usually takes place within a container, generally a servlet or a J2EE container. A Web service that uses a messaging provider and is deployed in a container has the capability of doing one-way messaging, meaning that it can receive a request as a one-way message and can return a response some time later as another one-way message.

Because of the features that a messaging provider can supply, JAXM can sometimes be a better choice for SOAP messaging than JAX-RPC. The following list includes features that JAXM can provide and that RPC, including JAX-RPC, does not generally provide:

  • One-way (asynchronous) messaging

  • Routing of a message to more than one party

  • Reliable messaging with features such as guaranteed delivery

A JAXM message is made up of two parts, a required SOAP part and an optional attachment part. The SOAP part, which consists of a SOAPEnvelope object containing a SOAPHeader object and a SOAPBody object. The SOAPBody object can hold XML fragments as the content of the message being sent. If you want to send content that is not in XML format or that is an entire XML document, your message will need to contain an attachment part in addition to the SOAP part. There is no limitation on the content in the attachment part, so it can include images or any other kind of content, including XML fragments and documents.

Getting a Connection

The first thing a JAXM client needs to do is get a connection, either a SOAPConnection object or a ProviderConnection object.

Getting a Point-to-Point Connection

A standalone client is limited to using a SOAPConnection object, which is a point-to-point connection that goes directly from the sender to the recipient. All JAXM connections are created by a connection factory. In the case of a SOAPConnection object, the factory is a SOAPConnectionFactory object. A client obtains the default implementation for SOAPConnectionFactory by calling the following line of code.

SOAPConnectionFactory factory =
        SOAPConnectionFactory.newInstance();

The client can use factory to create a SOAPConnection object.

SOAPConnection con = factory.createConnection();

Getting a Connection to the Messaging Provider

In order to use a messaging provider, an application must obtain a ProviderConnection object, which is a connection to the messaging provider rather than to a specified recipient. There are two ways to get a ProviderConnection object, the first being similar to the way a standalone client gets a SOAPConnection object. This way involves obtaining an instance of the default implementation for ProviderConnectionFactory, which is then used to create the connection.

ProviderConnectionFactory pcFactory =
      ProviderConnectionFactory.newInstance();
ProviderConnection pcCon = pcFactory.createConnection();

The variable pcCon represents a connection to the default implementation of a JAXM messaging provider.

The second way to create a ProviderConnection object is to retrieve a ProviderConnectionFactory object that is implemented to create connections to a specific messaging provider. The following code demonstrates getting such a ProviderConnectionFactory object and using it to create a connection. The first two lines use the JNDI API to retrieve the appropriate ProviderConnectionFactory object from the naming service where it has been registered with the name "CoffeeBreakProvider". When this logical name is passed as an argument, the method lookup returns the ProviderConnectionFactory object to which the logical name was bound. The value returned is a Java Object, which must be narrowed to a ProviderConnectionFactory object so that it can be used to create a connection. The third line uses a JAXM method to actually get the connection.

Context ctx = getInitialContext();
ProviderConnectionFactory pcFactory =  (ProviderConnectionFactory)ctx.lookup("CoffeeBreakProvider");
ProviderConnection con = pcFactory.createConnection();

The ProviderConnection instance con represents a connection to The Coffee Break's messaging provider.

Creating a Message

As is true with connections, messages are created by a factory. And similar to the case with connection factories, MessageFactory objects can be obtained in two ways. The first way is to get an instance of the default implementation for the MessageFactory class. This instance can then be used to create a basic SOAPMessage object.

MessageFactory messageFactory = MessageFactory.newInstance();
SOAPMessage m = messageFactory.createMessage();

All of the SOAPMessage objects that messageFactory creates, including m in the previous line of code, will be basic SOAP messages. This means that they will have no predefined headers.

Part of the flexibility of the JAXM API is that it allows a specific usage of a SOAP header. For example, protocols such as ebXML can be built on top of SOAP messaging. This usage of SOAP by a given standards group or industry is called a profile. In the second way to create a MessageFactory object, you use the ProviderConnection method createMessageFactory and give it a profile. The SOAPMessage objects produced by the resulting MessageFactory object will support the specified profile. For example, in the following code fragment, in which schemaURI is the URI of the schema for the desired profile, m2 will support the messaging profile that is supplied to createMessageFactory.

MessageFactory messageFactory2 =
          con.createMessageFactory(<schemaURI>);
SOAPMessage m2 = messageFactory2.createMessage();

Each of the new SOAPMessage objects m and m2 automatically contains the required elements SOAPPart, SOAPEnvelope, and SOAPBody, plus the optional element SOAPHeader (which is included for convenience). The SOAPHeader and SOAPBody objects are initially empty, and the following sections will illustrate some of the typical ways to add content.

Populating a Message

Content can be added to the SOAPPart object, to one or more AttachmentPart objects, or to both parts of a message.

Populating the SOAP Part of a Message

As stated earlier, all messages have a SOAPPart object, which has a SOAPEnvelope object containing a SOAPHeader object and a SOAPBody object. One way to add content to the SOAP part of a message is to create a SOAPHeaderElement object or a SOAPBodyElement object and add an XML document that you build with the method SOAPElement.addTextNode. The first three lines of the following code fragment access the SOAPBody object body, which is used to create a new SOAPBodyElement object and add it to body. The argument passed to the createName method is a Name object identifying the SOAPBodyElement being added. The last line adds the XML string passed to the method addTextNode.

SOAPPart sp = m.getSOAPPart();
SOAPEnvelope envelope = sp.getSOAPEnvelope();
SOAPBody body = envelope.getSOAPBody();
SOAPBodyElement bodyElement = body.addBodyElement(
        envelope.createName("text", "hotitems",
        "http://hotitems.com/products/gizmo");
bodyElement.addTextNode("some-xml-text");

Another way is to add content to the SOAPPart object by passing it a javax.xml.transform.Source object, which may be a SAXSource, DOMSource, or StreamSource object. The Source object contains content for the SOAP part of the message and also the information needed for it to act as source input. A StreamSource object will contain the content as an XML document; the SAXSource or DOMSource object will contain content and instructions for transforming it into an XML document.

The following code fragments illustrates adding content as a DOMSource object. The first step is to get the SOAPPart object from the SOAPMessage object. Next the code uses methods from the Java API for XML Processing (JAXP) to build the XML document to be added. It uses a DocumentBuilderFactory object to get a DocumentBuilder object. Then it parses the given file to produce the document that will be used to initialize a new DOMSource object. Finally, the code passes the DOMSource object domSource to the method SOAPPart.setContent.

SOAPPart soapPart = message.getSOAPPart();

DocumentBuilderFactory dbf=
      DocumentBuilderFactory.newInstance();
DocumentBuilder db = dbf.newDocumentBuilder();
Document doc = db.parse("file:///foo.bar/soap.xml");
DOMSource domSource = new DOMSource(doc);

soapPart.setContent(domSource);

Populating the Attachment Part of a Message

A Message object may have no attachment parts, but if it is to contain anything that is not in XML format, that content must be contained in an attachment part. There may be any number of attachment parts, and they may contain anything from plain text to image files. In the following code fragment, the content is an image in a JPEG file, whose URL is used to initialize the javax.activation.DataHandler object dh. The Message object m creates the AttachmentPart object attachPart, which is initialized with the data handler containing the URL for the image. Finally, the message adds attachPart to itself.

URL url = new URL("http://foo.bar/img.jpg");
DataHandler dh = new DataHandler(url);
AttachmentPart attachPart = m.createAttachmentPart(dh);
m.addAttachmentPart(attachPart);

A SOAPMessage object can also give content to an AttachmentPart object by passing an Object and its content type to the method createAttachmentPart.

AttachmentPart attachPart = 
  m.createAttachmentPart("content-string", "text/plain");
m.addAttachmentPart(attachPart);

A third alternative is to create an empty AttachmentPart object and then to pass the AttachmentPart.setContent method an Object and its content type. In this code fragment, the Object is a ByteArrayInputStream initialized with a jpeg image.

AttachmentPart ap = m.createAttachmentPart();
byte[] jpegData = ...;
ap.setContent(new ByteArrayInputStream(jpegData),
                "image/jpeg");
m.addAttachmentPart(ap);

1.6.4 Sending a Message

Once you have populated a SOAPMessage object, you are ready to send it. A standalone client uses the SOAPConnection method call to send a message. This method sends the message and then blocks until it gets back a response. The arguments to the method call are the message being sent and an Endpoint object that contains the URL of the receiver.

SOAPMessage response = 
        soapConnection.call(message, urlEndpoint);

An application that is using a messaging provider uses the ProviderConnection method send to send a message. This method sends the message asynchronously, meaning that it sends the message and returns immediately. The response, if any, will be sent as a separate operation at a later time. Note that this method takes only one parameter, the message being sent. The messaging provider will use header information to determine the destination.

providerConnection.send(message);
  • + Share This
  • 🔖 Save To Your Account

InformIT Promotional Mailings & Special Offers

I would like to receive exclusive offers and hear about products from InformIT and its family of brands. I can unsubscribe at any time.

Overview


Pearson Education, Inc., 221 River Street, Hoboken, New Jersey 07030, (Pearson) presents this site to provide information about products and services that can be purchased through this site.

This privacy notice provides an overview of our commitment to privacy and describes how we collect, protect, use and share personal information collected through this site. Please note that other Pearson websites and online products and services have their own separate privacy policies.

Collection and Use of Information


To conduct business and deliver products and services, Pearson collects and uses personal information in several ways in connection with this site, including:

Questions and Inquiries

For inquiries and questions, we collect the inquiry or question, together with name, contact details (email address, phone number and mailing address) and any other additional information voluntarily submitted to us through a Contact Us form or an email. We use this information to address the inquiry and respond to the question.

Online Store

For orders and purchases placed through our online store on this site, we collect order details, name, institution name and address (if applicable), email address, phone number, shipping and billing addresses, credit/debit card information, shipping options and any instructions. We use this information to complete transactions, fulfill orders, communicate with individuals placing orders or visiting the online store, and for related purposes.

Surveys

Pearson may offer opportunities to provide feedback or participate in surveys, including surveys evaluating Pearson products, services or sites. Participation is voluntary. Pearson collects information requested in the survey questions and uses the information to evaluate, support, maintain and improve products, services or sites, develop new products and services, conduct educational research and for other purposes specified in the survey.

Contests and Drawings

Occasionally, we may sponsor a contest or drawing. Participation is optional. Pearson collects name, contact information and other information specified on the entry form for the contest or drawing to conduct the contest or drawing. Pearson may collect additional personal information from the winners of a contest or drawing in order to award the prize and for tax reporting purposes, as required by law.

Newsletters

If you have elected to receive email newsletters or promotional mailings and special offers but want to unsubscribe, simply email information@informit.com.

Service Announcements

On rare occasions it is necessary to send out a strictly service related announcement. For instance, if our service is temporarily suspended for maintenance we might send users an email. Generally, users may not opt-out of these communications, though they can deactivate their account information. However, these communications are not promotional in nature.

Customer Service

We communicate with users on a regular basis to provide requested services and in regard to issues relating to their account we reply via email or phone in accordance with the users' wishes when a user submits their information through our Contact Us form.

Other Collection and Use of Information


Application and System Logs

Pearson automatically collects log data to help ensure the delivery, availability and security of this site. Log data may include technical information about how a user or visitor connected to this site, such as browser type, type of computer/device, operating system, internet service provider and IP address. We use this information for support purposes and to monitor the health of the site, identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents and appropriately scale computing resources.

Web Analytics

Pearson may use third party web trend analytical services, including Google Analytics, to collect visitor information, such as IP addresses, browser types, referring pages, pages visited and time spent on a particular site. While these analytical services collect and report information on an anonymous basis, they may use cookies to gather web trend information. The information gathered may enable Pearson (but not the third party web trend services) to link information with application and system log data. Pearson uses this information for system administration and to identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents, appropriately scale computing resources and otherwise support and deliver this site and its services.

Cookies and Related Technologies

This site uses cookies and similar technologies to personalize content, measure traffic patterns, control security, track use and access of information on this site, and provide interest-based messages and advertising. Users can manage and block the use of cookies through their browser. Disabling or blocking certain cookies may limit the functionality of this site.

Do Not Track

This site currently does not respond to Do Not Track signals.

Security


Pearson uses appropriate physical, administrative and technical security measures to protect personal information from unauthorized access, use and disclosure.

Children


This site is not directed to children under the age of 13.

Marketing


Pearson may send or direct marketing communications to users, provided that

  • Pearson will not use personal information collected or processed as a K-12 school service provider for the purpose of directed or targeted advertising.
  • Such marketing is consistent with applicable law and Pearson's legal obligations.
  • Pearson will not knowingly direct or send marketing communications to an individual who has expressed a preference not to receive marketing.
  • Where required by applicable law, express or implied consent to marketing exists and has not been withdrawn.

Pearson may provide personal information to a third party service provider on a restricted basis to provide marketing solely on behalf of Pearson or an affiliate or customer for whom Pearson is a service provider. Marketing preferences may be changed at any time.

Correcting/Updating Personal Information


If a user's personally identifiable information changes (such as your postal address or email address), we provide a way to correct or update that user's personal data provided to us. This can be done on the Account page. If a user no longer desires our service and desires to delete his or her account, please contact us at customer-service@informit.com and we will process the deletion of a user's account.

Choice/Opt-out


Users can always make an informed choice as to whether they should proceed with certain services offered by InformIT. If you choose to remove yourself from our mailing list(s) simply visit the following page and uncheck any communication you no longer want to receive: www.informit.com/u.aspx.

Sale of Personal Information


Pearson does not rent or sell personal information in exchange for any payment of money.

While Pearson does not sell personal information, as defined in Nevada law, Nevada residents may email a request for no sale of their personal information to NevadaDesignatedRequest@pearson.com.

Supplemental Privacy Statement for California Residents


California residents should read our Supplemental privacy statement for California residents in conjunction with this Privacy Notice. The Supplemental privacy statement for California residents explains Pearson's commitment to comply with California law and applies to personal information of California residents collected in connection with this site and the Services.

Sharing and Disclosure


Pearson may disclose personal information, as follows:

  • As required by law.
  • With the consent of the individual (or their parent, if the individual is a minor)
  • In response to a subpoena, court order or legal process, to the extent permitted or required by law
  • To protect the security and safety of individuals, data, assets and systems, consistent with applicable law
  • In connection the sale, joint venture or other transfer of some or all of its company or assets, subject to the provisions of this Privacy Notice
  • To investigate or address actual or suspected fraud or other illegal activities
  • To exercise its legal rights, including enforcement of the Terms of Use for this site or another contract
  • To affiliated Pearson companies and other companies and organizations who perform work for Pearson and are obligated to protect the privacy of personal information consistent with this Privacy Notice
  • To a school, organization, company or government agency, where Pearson collects or processes the personal information in a school setting or on behalf of such organization, company or government agency.

Links


This web site contains links to other sites. Please be aware that we are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of each and every web site that collects Personal Information. This privacy statement applies solely to information collected by this web site.

Requests and Contact


Please contact us about this Privacy Notice or if you have any requests or questions relating to the privacy of your personal information.

Changes to this Privacy Notice


We may revise this Privacy Notice through an updated posting. We will identify the effective date of the revision in the posting. Often, updates are made to provide greater clarity or to comply with changes in regulatory requirements. If the updates involve material changes to the collection, protection, use or disclosure of Personal Information, Pearson will provide notice of the change through a conspicuous notice on this site or other appropriate way. Continued use of the site after the effective date of a posted revision evidences acceptance. Please contact us if you have questions or concerns about the Privacy Notice or any objection to any revisions.

Last Update: November 17, 2020