Click here to close now.




















Welcome!

Related Topics: Java IoT

Java IoT: Article

Building a J2ME Multimedia Messaging Service Client

Host your own MMS content server and more

The Wireless Messaging API (WMA) reference implementation supports short message service (SMS) text and binary messages, but leaves the implementation of the hot area of multimedia messaging untouched. This article will demonstrate how to build a Multimedia Messaging Service (MMS) client using J2ME so you can get started writing new applications using this technology. By doing your own J2ME client implementation, you can bypass carrier lock-in of the content server or Multimedia Messaging Service Center (MMSC), as well as build your own server-side MMS applications, which you couldn't do before outside of the carrier network.

Software Requirements
A number of software requirements are needed to test the MMS client application. To run the basic emulation environment, make sure you have Sun's Wireless Toolkit 2.1 and JDK 1.4.2 or higher, both downloadable at http://java.sun.com. Download and compile the latest source code for the MMS Client and tools, available at http://sourceforge.net/projects/jvending. Next, set up either a Web or application server to act as the content server for the multimedia messages. Finally, you'll need to download the Nokia Mobile Internet Toolkit 4.0 from www.forum.nokia.com.

MMS Notification and Retrieval
The push registry maintains a list of inbound connections to mobile devices. It's one of the most exciting and least used features of the MIDP 2.0 spec. Under MIDP 1.0, a network-based application needed to constantly establish a connection and poll an application server for events. This ate up airtime and cost the user money, making network-based J2ME applications infeasible in many cases.

You can register inbound connections in the push registry by adding the connection information to the JAD file or by explicitly invoking the registerConnection static method on the PushRegistry class. In the J2SE world, registration is equivalent to opening a ServerSocket connection and waiting for a connection. The snippet below shows how we can register the connections in the JAD.

MIDlet-Push-1: serversocket://:1236, org.jvending.messaging.mmclient.MmsMidlet, *
MIDlet-Push-2: datagram://:1235, org.jvending.messaging.mmclient.MmsMidlet, *
MIDlet-Push-3: sms://:1234, org.jvending.messaging.mmclient.MmsMidlet, *

Why would you need to register so many push connections? There are a number of different ways to push the message notification, depending on the carrier network. You may need to set up push interfaces to cover push-over TCP (serversocket), WDP/UDP (datagram), and SMS. For instance, if we have an active GPRS or CSD connection, the server application may decide to send the MMS notification on the datagram connection, without failing over to the SMS connection. This means our MMS message is effectively lost.

Let's show how notification works in a carrier environment. Prior to the recipient MMS user agent retrieving an MMS message, the network must notify the user agent that the message is awaiting retrieval. There are a number of different ways for this notification to take place. The most common are SMS or WDP/UDP. If the user does not have a data session established, the notification will come over an SMS bearer. If a session has been established, the server just needs to push the request to the device over WDP/UDP (WAP 1.2+) or TCP (WAP 2.0).

Figure 1 shows a typical configuration within a carrier network for connectionless (asynchronous) notification through SMS. In step 1, the MMSC contacts the Push Proxy Gateway (PPG), which handles the pushing of messages to the mobile device. Next, the PPG contacts the Short Message Service Center (SMSC). In steps 3 and 4, the SMS is delivered over the GPRS network to the mobile device. If the MIDlet is not active, the application management software (AMS) detects that an SMS is destined, say, for port 1234. The AMS starts an instance of MmsMidlet, which extracts the MMS notification message from the body of the SMS message to find the MMS content location. In step 5, our application on the mobile device initiates an HTTP/GET connection to the content server.

Keep in mind that in most networks the connection is over the Wireless Session Protocol (WSP), which has an encoding that the content server does not understand. For steps 6 and 7, the network routes the HTTP request to the WAP gateway. The WAP gateway translates the WSP binary encoded HTTP headers into normal HTTP headers and forwards the request (step 8) onto the content server. The content server now delivers the WSP encapsulated MMS message over HTTP back to the mobile device. The MmsMidlet receives the MMS message, decodes it, and displays the graphical content to the user.

Testing Message Notification and Retrieval over an SMS Bearer
Let's test out retrieving an MMS message. First we need to set up a content server, which is merely an application or Web server that stores the MMS content. You can find sample MMS files in the Nokia Mobile Toolkit. Place marketupdate.nosmil.mms on the application server at, say, http://localhost:8080/ ROOT/marketupdate.nos mil.mms.

Now we need to generate an MMS message notification package. Do this by instantiating the org.jvending.tools .mms.MNotificationGenerator class, with parameters filename and content URL location (http://localhost:8080/ ROOT/marketupdate.nosmil.mms), which points to the location of the MMS message on the content server. You now have an MMS notification message stored on your local file system.

Next, open the WMA console within the Wireless Toolkit utilities tool. Make sure you're using version 2.1, since version 2.0 has a problem binary encoding characters within the 128-159 range. Click the "Send SMS" button followed by the Binary SMS tab. Import the contents of the MMS message that you generated with the MNotificationGenerator and type in port number 1234 within the text field.

Open up the emulator and click the MmsMidlet. You'll get a message asking if it's okay to receive text (or SMS) messages. Click OK. Go back to the WMA console and click "Send". This sends the binary SMS that contains the MMS notification to the recipient MMS user agent. Look at the package structure in Figure 2; the SMS body contains the MMS headers.

The MMS client application decodes this message and determines that it is an MMS notification message. The client reads the content URL location, opens an HTTP connection to the content server, pulls down the MMS message containing the mymessage.mms (see Figure 3), and displays the content on the mobile device. I'll explain exactly how to do this in the next sections.

Decoding the Multimedia Message
The MultimediaParser instance has a parse method that takes a PeekInputStream instance and a multimedia message object as parameters. A multimedia message object consists of two primary parts: the MMS headers and the MIME body (see Figure 3). The MultimediaParser instance delegates construction of the multimedia message object to two other objects, the HeaderFieldParser and the MimeParser.

The HeaderFieldParser's primary responsibility is to hand off the PeekInputStream object to an instance of WspTokenizer, which tokenizes the input stream into header fields according to the WSP spec. WSP encoding is a compact binary form that reduces the size of the headers.

The way this works is that if the first octet (or byte) is in the range of 32-127, the header is a text string, which ends with a 0 or null octet. If the first octet is in the range of 128-255, the header is binary encoded. For instance, if the value is 151, this maps to a TO field, which is subsequently followed by an encoded string. The less common values that begin in the range 0-31 are of variable length and center largely around date values.

This type of encoding makes tokenizing of the multimedia messaging surprisingly simple. You can decompose MMS into one of the following tokens: Text-String, Quoted-String, Extension-media, Short-integer, Multi-octet-integer, and Unitvar-Integer. The last two are integers of variable length, not something we have to deal with very often within the Java world. Essentially, they are just 128 base numbers and can be handled accordingly. See the source code to see how to encode/decode multi-octets. (The source code can be downloaded from www.sys-con.com/java/sourcec.cfm.)

With the exception of octets in the range of 0-31, the WspTokenizer object can determine the exact token and how to read the header based on the first octet. If the value is less than 32, however, the tokenizer peeks ahead one octet to determine the path that it needs to tokenize the header (see Listing 1).

After tokenization, the HeaderFieldParser object passes those tokens to an instance of the HeaderFieldAssembler, which takes the tokens and assembles them into easily readable Field objects to store within the target MultimediaMessage object.

Now that the HeaderFieldParser object has finished decoding the MMS headers, the MultimediaParser passes control to an instance of MimeParser, provided that the message contains a Content-Type field. The MimeParser object now assembles the MultipartEntry objects for the various MIME types and places them within the instance of MultimediaMessage. Our target MultimediaMessage object is now complete and ready to pass to the MessageConnection object, covered in the next section.

Extending the Wireless Message API
The wireless message API consists of five interfaces:

  1. BinaryMessage
  2. Message
  3. MessageConnection
  4. MessageListener
  5. TextMessage
The BinaryMessage and TextMessage classes extend the Message interface. For this article, we add an additional class, MultimediaMessage, which also extends the message interface.

The javax.wireless.messaging. MessageConnection class has its own implementation on the mobile devices. Modifying this implementation to return MultimediaMessage objects would require recompiling core MIDP 2.0 classes. Thus, the MMS client has its own implementation called org.jvending.messaging.MessageConnection, which functions in the same way with the same API. Look at the receive method of org.jvending.messaging.MessageConnection. This implementation accepts two kinds of connections: HTTP and SMS, both of which return a Message object of type MultimediaMessage.

If the URL connection is HTTP based, invoking the receive method on the MessageConnection instance results in the mobile device initiating an HTTP connection to the content server and pulling down an MMS message. The MessageConnection object casts the connection as an HttpConnection and invokes the openInputStream method to obtain an InputStream object. This does not involve the WMA messaging functionality

If the connection is SMS, we leverage the WMA by casting the connection as javax.wireless.messaging.MessageConnection and receiving a BinaryMessage. We now need to get it into an InputStream object since this type is required to pass into the instance of MultimediaParser. This requires invoking the getPayloadData() method on the BinaryMessage and feeding this in as a parameter to an instance of ByteArrayInputStream.

Finally, the MessageConnection object creates an instance of PeekInputStream and then invokes the parse method on the MultimediaParser object. The target MultimediaMessage object is now filled with all the MMS headers and MIME entries. Note that the MessageConnection is not concerned with the type of MMS message or how to handle notification and retrieval flow. The MmsMidlet client handles this logic (see Listing 2).

The MMS Client
The org.jvending.messaging. mmsclient package contains two classes: the MmsMidlet, which contains the logic for instantiating MessageConnection classes; and the MultimediaViewer class, which handles the display of the headers and media types. The first thing the MmsMidlet does is open an SMS connection and then wait to receive a MultimediaMessage on port 1234 (of course, in the actual source code this is threaded).

When the MMS notification comes over the SMS bearer, the MmsMidlet strips out the body and confirms that it is an M_NOTIFICATION message type. The MmsMidlet object takes the content URL location from the MMS notification and uses it as a parameter when invoking the open method on the Connector class. As discussed in the previous section, invoking the receive method on the MessageConnection returns a MultimediaMessage object containing the MIME entries. Next the MmsMidlet passes the MultimediaObject to an instance of MultimediaViewer that will, in turn, display the media content on the user's device (see Listing 3).

Conclusion
In the wireless data area, innovation and development are often difficult because carriers tightly couple device applications and server-side services. When you use J2ME and J2EE together to build client and server applications, it enables you to bypass many of these constraints. All it takes is access to basic SMS and HTTP protocols.

This article illustrates this flexibility by showing how building a J2ME MMS client allows developers to host their own MMS content server. This article also covers the basics of MMS retrieval and notification. The source code contains an MMS encoder that allows the user to send MMS messages. When combined with the Mobile Media API (JSR 135), this provides the ability to create a lot of interesting applications. You can find the latest updates and complete source code at http://sourceforge.net/projects/jvending.

Resources

  • Le Bodic, G. (2003). Mobile Messaging Technologies and Services. Wiley.
  • Metsker, S.J. (2001). Building Parsers with Java. Addison-Wesley.
  • now.sms: www.nowsms.com/messages/index.htm
  • Open Mobile Alliance, OMA-MMS-ENC-v1_1-20021030-C: Multimedia Messaging Service Encapsulation Protocol version 1.1, October 2002.
  • WAP Forum, WAP-230-WSP: Wireless Application Protocol, Wireless Session Protocol Specification Version 5, July 2001
  • More Stories By Shane Isbell

    Shane Isbell works as a software architect at a wireless carrier.

    Comments (0)

    Share your thoughts on this story.

    Add your comment
    You must be signed in to add a comment. Sign-in | Register

    In accordance with our Comment Policy, we encourage comments that are on topic, relevant and to-the-point. We will remove comments that include profanity, personal attacks, racial slurs, threats of violence, or other inappropriate material that violates our Terms and Conditions, and will block users who make repeated violations. We ask all readers to expect diversity of opinion and to treat one another with dignity and respect.


    Latest Stories
    WebRTC has had a real tough three or four years, and so have those working with it. Only a few short years ago, the development world were excited about WebRTC and proclaiming how awesome it was. You might have played with the technology a couple of years ago, only to find the extra infrastructure requirements were painful to implement and poorly documented. This probably left a bitter taste in your mouth, especially when things went wrong.
    Skeuomorphism usually means retaining existing design cues in something new that doesn’t actually need them. However, the concept of skeuomorphism can be thought of as relating more broadly to applying existing patterns to new technologies that, in fact, cry out for new approaches. In his session at DevOps Summit, Gordon Haff, Senior Cloud Strategy Marketing and Evangelism Manager at Red Hat, discussed why containers should be paired with new architectural practices such as microservices rathe...
    SYS-CON Events announced today that G2G3 will exhibit at SYS-CON's @DevOpsSummit Silicon Valley, which will take place on November 3–5, 2015, at the Santa Clara Convention Center in Santa Clara, CA. Based on a collective appreciation for user experience, design, and technology, G2G3 is uniquely qualified and motivated to redefine how organizations and people engage in an increasingly digital world.
    Any Ops team trying to support a company in today’s cloud-connected world knows that a new way of thinking is required – one just as dramatic than the shift from Ops to DevOps. The diversity of modern operations requires teams to focus their impact on breadth vs. depth. In his session at DevOps Summit, Adam Serediuk, Director of Operations at xMatters, Inc., will discuss the strategic requirements of evolving from Ops to DevOps, and why modern Operations has begun leveraging the “NoOps” approa...
    Too often with compelling new technologies market participants become overly enamored with that attractiveness of the technology and neglect underlying business drivers. This tendency, what some call the “newest shiny object syndrome,” is understandable given that virtually all of us are heavily engaged in technology. But it is also mistaken. Without concrete business cases driving its deployment, IoT, like many other technologies before it, will fade into obscurity.
    Organizations from small to large are increasingly adopting cloud solutions to deliver essential business services at a much lower cost. According to cyber security experts, the frequency and severity of cyber-attacks are on the rise, causing alarm to businesses and customers across a variety of industries. To defend against exploits like these, a company must adopt a comprehensive security defense strategy that is designed for their business. In 2015, organizations such as United Airlines, Sony...
    The Internet of Things is in the early stages of mainstream deployment but it promises to unlock value and rapidly transform how organizations manage, operationalize, and monetize their assets. IoT is a complex structure of hardware, sensors, applications, analytics and devices that need to be able to communicate geographically and across all functions. Once the data is collected from numerous endpoints, the challenge then becomes converting it into actionable insight.
    Puppet Labs has announced the next major update to its flagship product: Puppet Enterprise 2015.2. This release includes new features providing DevOps teams with clarity, simplicity and additional management capabilities, including an all-new user interface, an interactive graph for visualizing infrastructure code, a new unified agent and broader infrastructure support.
    Consumer IoT applications provide data about the user that just doesn’t exist in traditional PC or mobile web applications. This rich data, or “context,” enables the highly personalized consumer experiences that characterize many consumer IoT apps. This same data is also providing brands with unprecedented insight into how their connected products are being used, while, at the same time, powering highly targeted engagement and marketing opportunities. In his session at @ThingsExpo, Nathan Trel...
    Amazon and Google have built software-defined data centers (SDDCs) that deliver massively scalable services with great efficiency. Yet, building SDDCs has proven to be a near impossibility for ‘normal’ companies without hyper-scale resources. In his session at 17th Cloud Expo, David Cauthron, founder and chief executive officer of Nimboxx, will discuss the evolution of virtualization (hardware, application, memory, storage) and how commodity / open source hyper converged infrastructure (HCI) so...
    In their Live Hack” presentation at 17th Cloud Expo, Stephen Coty and Paul Fletcher, Chief Security Evangelists at Alert Logic, will provide the audience with a chance to see a live demonstration of the common tools cyber attackers use to attack cloud and traditional IT systems. This “Live Hack” uses open source attack tools that are free and available for download by anybody. Attendees will learn where to find and how to operate these tools for the purpose of testing their own IT infrastructu...
    The web app is agile. The REST API is agile. The testing and planning are agile. But alas, data infrastructures certainly are not. Once an application matures, changing the shape or indexing scheme of data often forces at best a top down planning exercise and at worst includes schema changes that force downtime. The time has come for a new approach that fundamentally advances the agility of distributed data infrastructures. Come learn about a new solution to the problems faced by software organ...
    With the Apple Watch making its way onto wrists all over the world, it’s only a matter of time before it becomes a staple in the workplace. In fact, Forrester reported that 68 percent of technology and business decision-makers characterize wearables as a top priority for 2015. Recognizing their business value early on, FinancialForce.com was the first to bring ERP to wearables, helping streamline communication across front and back office functions. In his session at @ThingsExpo, Kevin Roberts...
    IBM’s Blue Box Cloud, powered by OpenStack, is now available in any of IBM’s globally integrated cloud data centers running SoftLayer infrastructure. Less than 90 days after its acquisition of Blue Box, IBM has integrated its Blue Box Cloud Dedicated private-cloud-as-a-service into its broader portfolio of OpenStack® based solutions. The announcement, made today at the OpenStack Silicon Valley event, further highlights IBM’s continued support to deliver OpenStack solutions across all cloud depl...
    Red Hat is investing in Tesora, the number one contributor to OpenStack Trove Database as a Service (DBaaS) also ranked among the top 20 companies contributing to OpenStack overall. Tesora, the company bringing OpenStack Trove Database as a Service (DBaaS) to the enterprise, has announced that Red Hat and others have invested in the company as a part of Tesora's latest funding round. The funding agreement expands on the ongoing collaboration between Tesora and Red Hat, which dates back to Febr...