Java IoT Authors: Andreas Grabner, Roger Strukhoff, Carmen Gonzalez, John Mertic, Ruxit Blog

Related Topics: Java IoT

Java IoT: Article

A Time Zone Patch

A flexible solution

The java.util.TimeZone abstract class that represents a time zone is used to produce local time for a particular global time zone. A TimeZone comprises three basic pieces of information: an ID, a time zone offset, and the logic necessary to deal with DST (Daylight Savings Time).

While working with the TimeZone class provided with JRE 1.3 and 1.4, however, I discovered that it provides erroneous times for several time zones. This article describes this DST transition date problem, presents TimeZone test scenarios, and introduces TimeZonePatch. This patch is a flexible solution that enables the java.util.TimeZone to produce correct time zone data.

TimeZone Problem
I encountered the problem while working in a Java application that delivers Short Message Service (SMS) to wireless devices. The company's SMS application was being used in several countries and users were registering from several distinct time zones. A key requirement for the application is to have the user's local time as part of the SMS message.

The TimeZone JRE class was being used to retrieve the user's local time in the SMS message according to the user's registered time zone. It was discovered, however, that the application was delivering erroneous local times, and further investigation showed that the DST transition dates were not accurate for a number of time zones.

Testing TimeZone
The following test case was used to identify the time zone DST transition dates problem. It's based on the JUnit framework and is composed by TestTimeZone and DST classes (see Listings 1 and 2, respectively). The source code can be downloaded from www.caroli.org.

The correct DST entry and exit dates can be selected from trusted sources. For this article the dates were selected from the world clock Web site: www.timeanddate.com/worldclock/full.html.

To verify the DST transition problem the TestTimeZone test case was executed for two distinct time zones: America/Sao_Paulo and America/Santiago. The time zone data in the DST classes was retrieved from the world clock Web site.The tests results are depicted in Figures 1 and 2. Note that these tests are based on the JDK TimeZone class usage.

TimeZone Test 1:
America/Santiago time zone

public class DST{
public static final String DATE_FORMAT = "MM/dd/yyyy";
public static final String START_DST = "10/10/2004";
public static final String END_DST = "03/14/2004";
public static final String TIMEZONE_LOCATION = "America/Santiago";

TimeZone Test 2:
America/Sao_Paulo time zone

public class DST{
public static final String DATE_FORMAT = "MM/dd/yyyy";
public static final String START_DST = "11/02/2004";
public static final String END_DST = "02/15/2005";
public static final String TIMEZONE_LOCATION = "America/Sao_Paulo";

Test 2 for TimeZone shows the inaccuracy in the DST entry date of the TimeZone class with the America/Sao_Paulo time zone.

Patching TimeZone
The tests were executed with JRE 1.3 and 1.4 and both showed the same problem. Both versions of the TimeZone class read time zone IDs from the the tzmappings file in the jre/lib subdirectory. JRE 1.4 also contains time zone data files for various world regions in the jre/lib/zi subdirectory.

One solution for the 1.4 TimeZone class is to update the time zone files; however, these are binary and its change is dependent on you having access to and intimate knowledge of the JRE. The JRE provider could supply updates to the time zone files, however, it's not straightforward even for them to keep track of all the time zones' correct data. Although there are conventions about the DST transition dates and times, countries have the freedom to decide their own transition dates and times, and this has occurred in several places.

For these reasons I developed a patch for the SDK TimeZone, which solves the wrong DST transition dates problem independent of the original TimeZone implementation.

TimeZone Test Set-Up

public class TestTimeZone extends TestCase {
protected void setUp() throws Exception {
// timeZone = TimeZonePatch.getTimeZone(DST.TIMEZONE_LOCATION);
timeZone = TimeZone.getTimeZone(DST.TIMEZONE_LOCATION);

The TimeZonePatch class has been created for patching time zones according to an elected time zone data source. Listing 3 shows the TimeZonePatch code.

The fix works by having the TimeZonePatch class return your desired version of TimeZone. In case there is a time zone correction, this correction will be set in the timezonePatchList, which holds the patched TimeZone's objects. The TimeZonePatchListFactory class builds timezonePatchList.

A Factory of Your Time Zone Data
TimeZonePatchListFactory can get the time zone data from different sources. For example, the time zone data source can be an XML file, text file, database, Web service, or any other data source appropriate for your application.

Listing 4 shows TimeZonePatchListFactory, a Factory Method implementation that creates a time zone patch list based on an XML time zone data source. (Listings 4-6 can be downloaded from www.sys-con.com/java/sourcec.cfm.)

Listing 5 has timezonePatch.xml, an XML data source read by TimeZonePatchListFactory for patching the America/Sao_Paulo time zone.

The presented TimeZonePatchListFactory implementation uses JOX (Java Objects in XML) library for reading the XML file into the TimeZonePatchList JavaBean.

When reading the XML document, a mapping between the root node name - TimezonePatchList - and the nested nodes - timezonePatch, dst, startDate, and endDate - is automatically made for the TimeZonePatchList bean, and the nested beans - TimeZonePatch, DST, and Date - respectively.

More Stories By Paulo Caroli

Paulo Caroli, www.caroli.org, is the J2EE architect at blah!, a Telecom Italia Mobile (TIM) value-added services provider. Paulo has a master's degree in software engineering and is a Sun Certified Architect for Java Technology, with expertise in high-performance enterprise application development.

Comments (2) 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
sven van t veer 04/01/05 11:07:45 AM EST

The way I see it, the problem was originally found by Marcelo Lavor. The study was done by myself and Bruno Goyanna. The actual implementation as far as I know was done by Bruno since I'd already left the company.

It's nice to be able to take credit for the work of others.

Jack Schueler 01/13/05 09:39:18 AM EST

public class DST{
public static final String DATE_FORMAT = "MM/dd/yyyy";
public static final String START_DST = "10/10/2004";
public static final String END_DST = "03/14/2004";
public static final String TIMEZONE_LOCATION = "America/Santiago";
Should this
END_DST = "03/14/2004";
be this
END_DST = "03/14/2005";
to put your end date after your start date?

@ThingsExpo Stories
What happens when the different parts of a vehicle become smarter than the vehicle itself? As we move toward the era of smart everything, hundreds of entities in a vehicle that communicate with each other, the vehicle and external systems create a need for identity orchestration so that all entities work as a conglomerate. Much like an orchestra without a conductor, without the ability to secure, control, and connect the link between a vehicle’s head unit, devices, and systems and to manage the ...
What are the successful IoT innovations from emerging markets? What are the unique challenges and opportunities from these markets? How did the constraints in connectivity among others lead to groundbreaking insights? In her session at @ThingsExpo, Carmen Feliciano, a Principal at AMDG, will answer all these questions and share how you can apply IoT best practices and frameworks from the emerging markets to your own business.
More and more brands have jumped on the IoT bandwagon. We have an excess of wearables – activity trackers, smartwatches, smart glasses and sneakers, and more that track seemingly endless datapoints. However, most consumers have no idea what “IoT” means. Creating more wearables that track data shouldn't be the aim of brands; delivering meaningful, tangible relevance to their users should be. We're in a period in which the IoT pendulum is still swinging. Initially, it swung toward "smart for smar...
In past @ThingsExpo presentations, Joseph di Paolantonio has explored how various Internet of Things (IoT) and data management and analytics (DMA) solution spaces will come together as sensor analytics ecosystems. This year, in his session at @ThingsExpo, Joseph di Paolantonio from DataArchon, will be adding the numerous Transportation areas, from autonomous vehicles to “Uber for containers.” While IoT data in any one area of Transportation will have a huge impact in that area, combining sensor...
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 impr...
Successful digital transformation requires new organizational competencies and capabilities. Research tells us that the biggest impediment to successful transformation is human; consequently, the biggest enabler is a properly skilled and empowered workforce. In the digital age, new individual and collective competencies are required. In his session at 19th Cloud Expo, Bob Newhouse, CEO and founder of Agilitiv, will draw together recent research and lessons learned from emerging and established ...
The best way to leverage your Cloud Expo presence as a sponsor and exhibitor is to plan your news announcements around our events. The press covering Cloud Expo and @ThingsExpo will have access to these releases and will amplify your news announcements. More than two dozen Cloud companies either set deals at our shows or have announced their mergers and acquisitions at Cloud Expo. Product announcements during our show provide your company with the most reach through our targeted audiences.
Amazon has gradually rolled out parts of its IoT offerings, but these are just the tip of the iceberg. In addition to optimizing their backend AWS offerings, Amazon is laying the ground work to be a major force in IoT - especially in the connected home and office. In his session at @ThingsExpo, Chris Kocher, founder and managing director of Grey Heron, explained how Amazon is extending its reach to become a major force in IoT by building on its dominant cloud IoT platform, its Dash Button strat...
@ThingsExpo has been named the Top 5 Most Influential M2M Brand by Onalytica in the ‘Machine to Machine: Top 100 Influencers and Brands.' Onalytica analyzed the online debate on M2M by looking at over 85,000 tweets to provide the most influential individuals and brands that drive the discussion. According to Onalytica the "analysis showed a very engaged community with a lot of interactive tweets. The M2M discussion seems to be more fragmented and driven by some of the major brands present in the...
We are reaching the end of the beginning with WebRTC, and real systems using this technology have begun to appear. One challenge that faces every WebRTC deployment (in some form or another) is identity management. For example, if you have an existing service – possibly built on a variety of different PaaS/SaaS offerings – and you want to add real-time communications you are faced with a challenge relating to user management, authentication, authorization, and validation. Service providers will w...
DevOps is being widely accepted (if not fully adopted) as essential in enterprise IT. But as Enterprise DevOps gains maturity, expands scope, and increases velocity, the need for data-driven decisions across teams becomes more acute. DevOps teams in any modern business must wrangle the ‘digital exhaust’ from the delivery toolchain, "pervasive" and "cognitive" computing, APIs and services, mobile devices and applications, the Internet of Things, and now even blockchain. In this power panel at @...
SYS-CON Media announced today that @WebRTCSummit Blog, the largest WebRTC resource in the world, has been launched. @WebRTCSummit Blog offers top articles, news stories, and blog posts from the world's well-known experts and guarantees better exposure for its authors than any other publication. @WebRTCSummit Blog can be bookmarked ▸ Here @WebRTCSummit conference site can be bookmarked ▸ Here
One of biggest questions about Big Data is “How do we harness all that information for business use quickly and effectively?” Geographic Information Systems (GIS) or spatial technology is about more than making maps, but adding critical context and meaning to data of all types, coming from all different channels – even sensors. In his session at @ThingsExpo, William (Bill) Meehan, director of utility solutions for Esri, will take a closer look at the current state of spatial technology and ar...
SYS-CON Events announced today that Streamlyzer 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. Streamlyzer is a powerful analytics for video streaming service that enables video streaming providers to monitor and analyze QoE (Quality-of-Experience) from end-user devices in real time.
You have great SaaS business app ideas. You want to turn your idea quickly into a functional and engaging proof of concept. You need to be able to modify it to meet customers' needs, and you need to deliver a complete and secure SaaS application. How could you achieve all the above and yet avoid unforeseen IT requirements that add unnecessary cost and complexity? You also want your app to be responsive in any device at any time. In his session at 19th Cloud Expo, Mark Allen, General Manager of...
SYS-CON Events announced today that SoftNet Solutions 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. SoftNet Solutions specializes in Enterprise Solutions for Hadoop and Big Data. It offers customers the most open, robust, and value-conscious portfolio of solutions, services, and tools for the shortest route to success with Big Data. The unique differentiator is the ability to architect and ...
The IoT industry is now at a crossroads, between the fast-paced innovation of technologies and the pending mass adoption by global enterprises. The complexity of combining rapidly evolving technologies and the need to establish practices for market acceleration pose a strong challenge to global enterprises as well as IoT vendors. In his session at @ThingsExpo, Clark Smith, senior product manager for Numerex, will discuss how Numerex, as an experienced, established IoT provider, has embraced a ...
Cloud based infrastructure deployment is becoming more and more appealing to customers, from Fortune 500 companies to SMEs due to its pay-as-you-go model. Enterprise storage vendors are able to reach out to these customers by integrating in cloud based deployments; this needs adaptability and interoperability of the products confirming to cloud standards such as OpenStack, CloudStack, or Azure. As compared to off the shelf commodity storage, enterprise storages by its reliability, high-availabil...
Donna Yasay, President of HomeGrid Forum, today discussed with a panel of technology peers how certification programs are at the forefront of interoperability, and the answer for vendors looking to keep up with today's growing industry for smart home innovation. "To ensure multi-vendor interoperability, accredited industry certification programs should be used for every product to provide credibility and quality assurance for retail and carrier based customers looking to add ever increasing num...
SYS-CON Events announced today that Super Micro Computer, Inc., a global leader in Embedded and IoT solutions, will exhibit at SYS-CON's 20th International Cloud Expo®, which will take place on June 7-9, 2017, at the Javits Center in New York City, NY. Supermicro (NASDAQ: SMCI), the leading innovator in high-performance, high-efficiency server technology, is a premier provider of advanced server Building Block Solutions® for Data Center, Cloud Computing, Enterprise IT, Hadoop/Big Data, HPC and ...