Welcome!

Java IoT Authors: AppDynamics Blog, Liz McMillan, Pat Romanski, Craig Lowell, Akhil Sahai

Related Topics: Java IoT

Java IoT: Article

GUI Design Patterns

Choosing data from long lists

Long lists of data present a problem for GUI development. This occurs when choosing records from large database tables or recipients from a long list of e-mail addresses, or any time a subset of data must be chosen from a long list or table.

Two issues arise when choosing from long lists of data. First, what is the best GUI for long lists so that the users understand how to navigate and manipulate their data? Second, if the list holds more than a few hundred items, performance become an issue.

In this article, simple examples show how to optimize usability for this common GUI design pattern. In a later article, more complex examples will show how to optimize performance for long lists.

GUI Design Patterns
In the late 1990s, a GUI design pattern emerged for choosing multiple objects from long lists. The book GUI Design Essentials by Susan Weinschenk, et al, called this the Selection Summary pattern. In "A Dual Listbox Selection Manager" by Steve Aube, it's also known as the Dual Listbox Selection interface. In "The Java Look and Feel Guidelines, Advanced Topics" by Sun Microsystems, it's called the Add-and-Remove idiom. Figure 1 shows an example of this GUI design pattern.

The Add-and-Remove design pattern has many variations. One common enhancement is to provide "Move Up" and "Move Down" buttons to reorder the chosen list. Sometimes the chosen list is displayed as a table (as in Figure 2) to show additional information.

This GUI design pattern has several advantages. By presenting the original and chosen lists in a symmetric layout, learning is simplified: once users learn one part of the GUI, the corresponding part works consistently. Also, because objects are moved from one location to another, directional icons and disabling can be used to guide the user.

The most important advantage of a standard GUI design like this is that because it is widely known, users will most likely have seen it before and therefore understand it quickly. A standard GUI design pattern is the simplest way to achieve usability.

Lay Out the Components
Listing 1 shows how this GUI design pattern can be implemented using the Swing components JList, JScrollPane, ImageIcon, and GridBagLayout. The GridBagLayout enables the alignment of unequal-sized components and provides good behavior on resizing. For a basic implementation, we need a grid with three columns and five rows. Lists, labels, and buttons are placed using GridBagConstraints so that when the component is resized, the lists grow or shrink while other components retain their original size (see Figure 3).

To support the Add-and-Remove pattern, the list contents must be mutable; i.e., the lists must dynamically change in response to the button presses. The DefaultListModel provides mutable storage that performs satisfactorily for lists of moderate size.

In Listing 1, the ActionListener interface connects the buttons to the lists. The actionPerformed method uses the button text to determine which of the four buttons was pressed.

The code in Listing 1 produces the GUI shown in Figure 4.

The DefaultListModel is not the default ListModel. By default, JLists use an internal ListModel that is immutable: you can't change its contents. This internal ListModel is efficient when applications only need to view a list because it doesn't carry the overhead of changing list contents.

To change list contents, as in the Add-and-Remove pattern, requires a mutable ListModel. Swing provides one in javax.swing.DefaultListModel, and it gives good performance for most applications. For long lists DefaultListModel is not particularly fast, and a later article will show how to improve on its performance.

Follow the Guidelines
"The Java Look and Feel Guidelines" specify precise spacings in multiples of six pixels between components. To follow these guidelines, EmptyBorders are added around the buttons and labels.

_originalLabel.setBorder(
  BorderFactory.createEmptyBorder( 0, 0, 6, 0 ));
_chosenLabel.setBorder(
  BorderFactory.createEmptyBorder( 0, 0, 6, 0 ));
_add.setBorder(
  BorderFactory.createCompoundBorder(
  BorderFactory.createEmptyBorder( 0, 11, 5, 11 ),
  _add.getBorder()));
_addAll.setBorder(
  BorderFactory.createCompoundBorder(
  BorderFactory.createEmptyBorder( 0, 11, 11, 11 ),
  _addAll.getBorder()));
_remove.setBorder(
  BorderFactory.createCompoundBorder(
  BorderFactory.createEmptyBorder( 0, 11, 5, 11 ),
  _remove.getBorder()));
_removeAll.setBorder(
  BorderFactory.createCompoundBorder(
  BorderFactory.createEmptyBorder( 0, 11, 0, 11 ),
  _removeAll.getBorder()));

The Guidelines also recommend mnemonics to support keyboard equivalents of mouse actions, as shown in the code below.

_add.setMnemonic( 'A' );
_addAll.setMnemonic( 'l' );
_remove.setMnemonic( 'R' );
_removeAll.setMnemonic( 'v' );

Note the difference between Figures 4 and 5. By following the guidelines, the GUI appearance is improved.

This example uses the guidelines for the Java ("Metal") Look and Feel. If you target a different platform the guidelines will be different. For example, Windows Guidelines specify different spacings between the components.

Whatever the target platform, the reason for following guidelines is to make life easier for the user. When your application looks and works the way the users expect, they have less to learn.

Help the Users Learn
"The Java Look and Feel Guidelines, Advanced Topics" by Sun recommends the use of icons in the buttons. If icons are stored with the ListChooser class, they can be assigned with the following code.

_add.setIcon( new ImageIcon(
  ListSelector.class.getResource( "images/add.gif" )));
_add.setHorizontalTextPosition( SwingConstants.LEFT );
_addAll.setIcon( new ImageIcon(
  ListSelector.class.getResource( "images/addAll.gif" )));
_addAll.setHorizontalTextPosition( SwingConstants.LEFT );
_remove.setIcon( new ImageIcon(
  ListSelector.class.getResource( "images/remove.gif" )));
_remove.setHorizontalTextPosition( SwingConstants.RIGHT );
_removeAll.setIcon( new ImageIcon(
  ListSelector.class.getResource( "images/removeAll.gif")));
_removeAll.setHorizontalTextPosition( SwingConstants.RIGHT );

These simple icons transform the buttons into a diagram of information flow through the GUI. The icons make the users' possible actions clear before they read the buttons' text, enabling new users to understand the buttons' functions at a glance.

The icons in Figure 6 are chosen because they're familiar to most users; similar icons appear on most tape and disk players. "The Java Look and Feel Guidelines, Advanced Topics" illustrate other icons specific to the Java look and feel. Whatever icons are chosen, the program should provide equal margins on the left and right to ensure consistent spacing between the icons and the button text. A slight margin below the icon, as shown in Figure 7, can improve vertical alignment.

Prevent User Errors
One of the best ways to improve usability is to prevent the user from making a mistake. The authors of GUI Design Essentials recommend disabling unavailable actions. This technique guides users through the GUI, preventing them from taking actions that make no sense.

This effective GUI design pattern is trivially easy to code. The ActionListener interface enables the "Add All" and "Remove All" buttons when the lists contain objects, and disables them when the lists are empty.

public void actionPerformed(
  ActionEvent e )
{    .
    .
    .
  _addAll.setEnabled(
   originalModel.getSize() > 0 );
  _removeAll.setEnabled(
   chosenModel.getSize() > 0 );
}

The ListSelectionListener interface enables the "Add" and "Remove" buttons when objects are selected, and disables them when no objects are selected.

public void valueChanged(
   ListSelectionEvent e )
{ _add.setEnabled( _originalList.
   getSelectedValues().length > 0 );
  _remove.setEnabled( _chosenList.
   getSelectedValues().length > 0 );
}

As shown in Listing 1, the ListChooser registers itself as an ActionListener to receive events when buttons are pressed. To receive events when list contents are selected, the ListChooser registers itself as a ListSelectionListener. Also, at the end of the constructor, two dummy events are initiated to set the default enabled states.

public ListChooser(
  Object[] original, Object[] chosen )
{     .
     .
     .
  _originalList.
   addListSelectionListener( this );
  _chosenList.
   addListSelectionListener( this );
  actionPerformed(
   new ActionEvent( this, 0, "" ));
  valueChanged(
   new ListSelectionEvent(
   this, 0, 0, false ));
}

The effect of this code is shown in Figure 8. Rather than trying to deal with the user pressing the wrong button, the program uses disabling to prevent the mistake from occurring. Disabling unavailable actions is one of the simplest and most effective GUI design patterns.

GUI Variations
All of the GUI design patterns described above apply to tables as well as lists. Listing 2 shows an implementation using JTable and TableModel instead of JList and ListModel. "The Java Look and Feel Guidelines" recommend only one table column in the original list and multiple columns in the chosen list. As shown in Listing 2, this can be done by disabling the header and grid lines in the original table, and by assigning the preferred viewport size based on TableColumn widths.

The GridBagLayout code is omitted from Listing 2 as it is similar to the simpler variation of Listing 1. If "Move Up" and "Move Down" buttons are provided, the GridBagLayout contains seven rows instead of five. Following "The Java Look and Feel Guidelines," the spacing between these optional buttons is six pixels greater than between the "Add" and "Remove" buttons.

The ActionListener implementation is slightly different in Listing 2 because of the use of TableModels instead of ListModels. The code in Listing 2 produces the GUI shown in Figure 2.

Details of the JTable and TableModel can be found in The JFC Swing Tutorial (by Kathy Walrath and Mary Campione), along with descriptions of the JList and ListModel. The JTable is more complex than the JList, but when displaying long lists they share many of the same performance issues. A future article will discuss these issues and how to optimize performance for this common GUI design pattern.

Conclusion
The Add-and-Remove pattern enables users to choose multiple objects from long lists. This standard GUI design pattern improves usability by easing the user's learning curve. Standard spacing, directional icons, and button disabling all reduce the users' efforts, enabling them to accomplish their tasks easily in a professional user interface.

Resources

  • Aube, S. (2000). "A Dual Listbox Selection Manager": www.codeguru.com/Cpp/controls/listbox/article.php/c4755
  • Walrath, K., and Campione, M. (2004). The JFC Swing Tutorial: A Guide to Constructing GUIs. Addison-Wesley Professional: java.sun.com/docs/books/tutorial/uiswing/components/
  • "Official Guidelines for User Interface Developers and Designers." Microsoft Inc. (2004): msdn.microsoft.com/library/default.asp?url=/library/en-us/dnwue/html/welcome.asp
  • Sun Microsystems Inc. (2001). Java Look and Feel Design Guidelines, Second Edition. Addison-Wesley Professional: java.sun.com/products/jlf/ed2/book/HIG.Misc.html
  • Sun MicroSystems Inc. (2002). Java Look and Feel Design Guidelines: Advanced Topics. Addison-Wesley Professional: java.sun.com/products/jlf/at/book/Idioms6.html
  • Weinschenk, S., Jamar, P., and Yeo, S. (1997). GUI Design Essentials. John Wiley & Sons.
  • More Stories By Heman Robinson

    Heman Robinson is a senior developer with SAS Institute in Cary, N.C. He holds a BS in mathematics from the University of North Carolina and an MS in computer science from the University of Southern California. He has specialized in GUI design and development for 15 years and has been a Java developer since 1996.

    Comments (1) View Comments

    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.


    Most Recent Comments
    steve 02/14/05 07:04:05 PM EST

    Does anyone have code that accomplishes this for VB.NET?

    @ThingsExpo Stories
    Early adopters of IoT viewed it mainly as a different term for machine-to-machine connectivity or M2M. This is understandable since a prerequisite for any IoT solution is the ability to collect and aggregate device data, which is most often presented in a dashboard. The problem is that viewing data in a dashboard requires a human to interpret the results and take manual action, which doesn’t scale to the needs of IoT.
    SYS-CON Events announced today that 910Telecom will exhibit at the 19th International Cloud Expo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. Housed in the classic Denver Gas & Electric Building, 910 15th St., 910Telecom is a carrier-neutral telecom hotel located in the heart of Denver. Adjacent to CenturyLink, AT&T, and Denver Main, 910Telecom offers connectivity to all major carriers, Internet service providers, Internet backbones and ...
    CenturyLink has announced that application server solutions from GENBAND are now available as part of CenturyLink’s Networx contracts. The General Services Administration (GSA)’s Networx program includes the largest telecommunications contract vehicles ever awarded by the federal government. CenturyLink recently secured an extension through spring 2020 of its offerings available to federal government agencies via GSA’s Networx Universal and Enterprise contracts. GENBAND’s EXPERiUS™ Application...
    IoT generates lots of temporal data. But how do you unlock its value? You need to discover patterns that are repeatable in vast quantities of data, understand their meaning, and implement scalable monitoring across multiple data streams in order to monetize the discoveries and insights. Motif discovery and deep learning platforms are emerging to visualize sensor data, to search for patterns and to build application that can monitor real time streams efficiently. In his session at @ThingsExpo, ...
    Verizon Communications Inc. (NYSE, Nasdaq: VZ) and Yahoo! Inc. (Nasdaq: YHOO) have entered into a definitive agreement under which Verizon will acquire Yahoo's operating business for approximately $4.83 billion in cash, subject to customary closing adjustments. Yahoo informs, connects and entertains a global audience of more than 1 billion monthly active users** -- including 600 million monthly active mobile users*** through its search, communications and digital content products. Yahoo also co...
    "There's a growing demand from users for things to be faster. When you think about all the transactions or interactions users will have with your product and everything that is between those transactions and interactions - what drives us at Catchpoint Systems is the idea to measure that and to analyze it," explained Leo Vasiliou, Director of Web Performance Engineering at Catchpoint Systems, in this SYS-CON.tv interview at 18th Cloud Expo, held June 7-9, 2016, at the Javits Center in New York Ci...
    "Tintri was started in 2008 with the express purpose of building a storage appliance that is ideal for virtualized environments. We support a lot of different hypervisor platforms from VMware to OpenStack to Hyper-V," explained Dan Florea, Director of Product Management at Tintri, in this SYS-CON.tv interview at 18th Cloud Expo, held June 7-9, 2016, at the Javits Center in New York City, NY.
    The best-practices for building IoT applications with Go Code that attendees can use to build their own IoT applications. In his session at @ThingsExpo, Indraneel Mitra, Senior Solutions Architect & Technology Evangelist at Cognizant, provided valuable information and resources for both novice and experienced developers on how to get started with IoT and Golang in a day. He also provided information on how to use Intel Arduino Kit, Go Robotics API and AWS IoT stack to build an application tha...
    SYS-CON Events announced today that LeaseWeb USA, a cloud Infrastructure-as-a-Service (IaaS) provider, will exhibit at the 19th International Cloud Expo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. LeaseWeb is one of the world's largest hosting brands. The company helps customers define, develop and deploy IT infrastructure tailored to their exact business needs, by combining various kinds cloud solutions.
    Whether your IoT service is connecting cars, homes, appliances, wearable, cameras or other devices, one question hangs in the balance – how do you actually make money from this service? The ability to turn your IoT service into profit requires the ability to create a monetization strategy that is flexible, scalable and working for you in real-time. It must be a transparent, smoothly implemented strategy that all stakeholders – from customers to the board – will be able to understand and comprehe...
    The cloud market growth today is largely in public clouds. While there is a lot of spend in IT departments in virtualization, these aren’t yet translating into a true “cloud” experience within the enterprise. What is stopping the growth of the “private cloud” market? In his general session at 18th Cloud Expo, Nara Rajagopalan, CEO of Accelerite, explored the challenges in deploying, managing, and getting adoption for a private cloud within an enterprise. What are the key differences between wh...
    SYS-CON Events announced today that Venafi, the Immune System for the Internet™ and the leading provider of Next Generation Trust Protection, will exhibit at @DevOpsSummit at 19th International Cloud Expo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. Venafi is the Immune System for the Internet™ that protects the foundation of all cybersecurity – cryptographic keys and digital certificates – so they can’t be misused by bad guys in attacks...
    Large scale deployments present unique planning challenges, system commissioning hurdles between IT and OT and demand careful system hand-off orchestration. In his session at @ThingsExpo, Jeff Smith, Senior Director and a founding member of Incenergy, will discuss some of the key tactics to ensure delivery success based on his experience of the last two years deploying Industrial IoT systems across four continents.
    There will be new vendors providing applications, middleware, and connected devices to support the thriving IoT ecosystem. This essentially means that electronic device manufacturers will also be in the software business. Many will be new to building embedded software or robust software. This creates an increased importance on software quality, particularly within the Industrial Internet of Things where business-critical applications are becoming dependent on products controlled by software. Qua...
    SYS-CON Events has announced today that Roger Strukhoff has been named conference chair of Cloud Expo and @ThingsExpo 2016 Silicon Valley. The 19th Cloud Expo and 6th @ThingsExpo will take place on November 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. "The Internet of Things brings trillions of dollars of opportunity to developers and enterprise IT, no matter how you measure it," stated Roger Strukhoff. "More importantly, it leverages the power of devices and the Interne...
    Machine Learning helps make complex systems more efficient. By applying advanced Machine Learning techniques such as Cognitive Fingerprinting, wind project operators can utilize these tools to learn from collected data, detect regular patterns, and optimize their own operations. In his session at 18th Cloud Expo, Stuart Gillen, Director of Business Development at SparkCognition, discussed how research has demonstrated the value of Machine Learning in delivering next generation analytics to imp...
    In addition to all the benefits, IoT is also bringing new kind of customer experience challenges - cars that unlock themselves, thermostats turning houses into saunas and baby video monitors broadcasting over the internet. This list can only increase because while IoT services should be intuitive and simple to use, the delivery ecosystem is a myriad of potential problems as IoT explodes complexity. So finding a performance issue is like finding the proverbial needle in the haystack.
    The Internet of Things will challenge the status quo of how IT and development organizations operate. Or will it? Certainly the fog layer of IoT requires special insights about data ontology, security and transactional integrity. But the developmental challenges are the same: People, Process and Platform. In his session at @ThingsExpo, Craig Sproule, CEO of Metavine, demonstrated how to move beyond today's coding paradigm and shared the must-have mindsets for removing complexity from the develo...
    SYS-CON Events announced today that MangoApps will exhibit at the 19th International Cloud Expo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. MangoApps provides modern company intranets and team collaboration software, allowing workers to stay connected and productive from anywhere in the world and from any device.
    Basho Technologies has announced the latest release of Basho Riak TS, version 1.3. Riak TS is an enterprise-grade NoSQL database optimized for Internet of Things (IoT). The open source version enables developers to download the software for free and use it in production as well as make contributions to the code and develop applications around Riak TS. Enhancements to Riak TS make it quick, easy and cost-effective to spin up an instance to test new ideas and build IoT applications. In addition to...