Welcome!

SOA & WOA Authors: Carmen Gonzalez, Pat Romanski, Elizabeth White, Victoria Livschitz, Larry Dragich

Related Topics: Java, XML, SOA & WOA, AJAX & REA

Java: Product Review

Design Patterns in Java LiveLessons Review

LiveLessons Video Training the Downloadable Version

I have spent the past few weeks watching this video series. I started watching it on the treadmill in the morning before work. I did that until I hit lesson 5. It is 4 hours and 20 minutes long. I started watching lesson 5 in front of the computer, not because I didn't want to walk for over four hours, but because I wanted to look at the code you can download with these lessons.

In lesson 5 covers a ton of patterns. The thing I like most about the way the patterns are introduced is that they are introduced working with other patterns. The way patterns should be used, together.

He uses lots of diagrams and walks through the tons of code making sure the patterns are thoroughly cover.

The thing I liked most about the course was that the speaker is not a pattern zealot. He makes sure to tell you when you would not want to use patterns and why. He gives the advantages and disadvantages of each pattern.

The downloadable code is very well organized and usable. It was really nice to just import the project, build it, and run it. No issues at all. I am not usually that lucky with Java samples.

You do not need to know Java to watch this course. I do very very little in Java. I am in Objective-C or C# 90% of the time I am in code. I do have a lot of experience with patterns at all levels (code, integration, architectural, information management, enterprise, etc.). Although you can do without Java, I do recommend you have OOP under your belt. I also felt having the past experience with pattern really helped me keep up.

If you don't have pattern experience, I think you may have to work a little harder to keep up. That is not a bad thing because the material covered is real worth the extra effort to get under your belt. The more you work at understanding the concepts the the speaker cover, the more embedded in your development thought process it will become.

Below is a brief overview of each lesson. They are taken from the publisher's web site.

Lesson 1:
Experts in most domains perform quite differently than beginners. For example, professional athletes, musicians, and dancers move fluidly and effortlessly, without focusing on each individual movement. Likewise, when master software developers write code, they approach it differently than novices, drawing on years of design experience to help guide their solutions.

When watching experts perform, it's often easy to forget how much effort they put into reaching these high levels of achievement. Continuous practice, repetition, and mentoring from other experts are crucial to their success. At the heart of all these activities is knowledge and mastery of patterns, which are reusable solutions to common problems that arise within particular contexts.

In this lesson you learn to recognize the importance of design experience when becoming a master software developer. You also learn what patterns are and how they help codify design experience to improve software quality and developer productivity. In addition, you learn the common characteristics of patterns and pattern descriptions. Finally, you learn about the history of the Gang of Four book and its patterns, as well as learn about key types of relationships among patterns.

Lesson 2:
While it’s certainly possible to discuss patterns in the abstract, good design and programming practices are not best learned through generalities and platitudes. Instead, it’s more effective to see how significant programs can be made easier to write and read, easier to maintain and modify, and more efficient and robust via the application of time-proven software patterns.

This lesson therefore presents an overview of an expression tree processing app that we use as a case study throughout the course. You learn about the goals of this case study, which provides a realistic–yet tractable–context in which to explore the why, the how, and the benefits and limitations of applying many Gang of Four design patterns to an application written in Java. Using the case study as a guide, you also learn how to recognize key structural and behavioral properties in a domain, as well as understand the case study's functional and non-functional requirements.

All the pattern-oriented software presented in the case study is available in open-source form from the course website. You can see throughout the course that applying Gang of Four patterns in the case study not only improves the application’s modularity, extensibility, and quality but also enhances its portability so that it runs on a range of Java platforms, including Android and Eclipse.

Lesson 3:
Algorithmic decomposition is a historically popular software development method that structures software based on the actions performed by algorithms in a program. It decomposes general actions in an algorithm iteratively and recursively into more specific actions. The design components in an algorithmic decomposition typically correspond to processing steps in an execution sequence, which are usually implemented via functions or procedures.

In this lesson you learn how to develop an algorithmic decomposition of the expression tree processing app case study. You also learn how to evaluate the benefits and limitations of algorithmic decomposition. This material provides a baseline for comparison with our pattern- and object-oriented expression tree processing app presented in subsequent lessons.

Lesson 4:
Object-oriented design is a method of planning a system of interacting objects to solve software problems. This design paradigm employs hierarchical data abstraction, where components are structured based on stable class/object roles and relationships, rather than functions corresponding to actions (as is the case with algorithmic decomposition). Moreover, object-oriented design associates actions with classes of objects in a manner that emphasizes high cohesion and low coupling. In many well-designed object-oriented programs, classes and objects are defined and associated in accordance with patterns and combined to form frameworks.

In this lesson you learn how to develop an object-oriented design for the expression tree processing app case study. In addition, you learn how to evaluate the benefits and limitations of object-oriented design relative to the algorithmic decomposition approach presented in Lesson 3.

Lesson 5:
The book Design Patterns: Elements of Reusable Object-Oriented Software (the so-called “Gang of Four” book) presents 23 patterns that document recurring solutions to common problems that arise when developing software in particular contexts. In this lesson you learn how more than a dozen patterns from the Gang of Four book can be applied to the Java-based expression tree processing app case study to resolve key design problems and improve the apps modularity, extensibility, portability, and quality. This lesson forms the bulk of the course and covers the following patterns:

• Composite, which treats individual objects and multiple, recursively-composed objects uniformly.
• Bridge, which separates an abstraction from its implementation(s) so the two can vary independently.
• Interpreter, which when given a language, defines a representation for its grammar.
• Builder, which separates the construction of a complex object from its representation.
• Iterator, which accesses elements of an aggregate without exposing its representation.
• Strategy, which defines a family of algorithms, encapsulates each one, and makes them interchangeable.
• Visitor, which centralizes operations on an object structure so that they can vary independently.
• Command, which encapsulates the request for a service as an object.
• Factory Method, which provides an interface for creating an object, but leaves the choice of the concrete type to a subclass.
• State, which allows an object to alter its behavior when its internal state changes, making object appear to change its class.
• Template Method, which provides a skeleton of an algorithm in a method, deferring some steps to subclasses.
• Singleton, which ensures a class only has one instance and provides a global point of access.

The lesson also touches on several other Gang of Four patterns, including Abstract Factory, Adaptor, Decorator, and Observer.

Lesson 6:
The pattern- and object-oriented version of the expression tree processing app case study presented in Lesson 5 provided many improvements compared with the algorithmic decomposition approach described in Lesson 3. For example, it's much more modular and extensible, its design matches the domain better, and it incurs less space overhead. The design of the expression tree process app also exhibits “high pattern density.” For instance, nearly all its classes play a role in one or more Gang of Four patterns. In addition, patterns help clarify the relationships of the many classes comprising the case study’s design. The same pattern-oriented design can be implemented readily in many popular object-oriented programming languages. For example, the Java and C++ solutions are nearly identical, modulo minor syntactic and semantic differences in these two languages. Although pattern- and object-oriented solutions are powerful, becoming a master software developer requires a balanced and nuanced understanding of the pros and cons of patterns. In this lesson, you learn how to evaluate both the benefits and limitations of patterns.

I highly recommend this video series to anyone working in an object oriented language.

Get the video series here.

If you have no design pattern experience at all, below are a few of the best available on the topic.

More Stories By Tad Anderson

Tad Anderson has been doing Software Architecture for 18 years and Enterprise Architecture for the past few.

@ThingsExpo Stories
The 3rd International Internet of @ThingsExpo, co-located with the 16th International Cloud Expo - to be held June 9-11, 2015, at the Javits Center in New York City, NY - announces that its Call for Papers is now open. The Internet of Things (IoT) is the biggest idea since the creation of the Worldwide Web more than 20 years ago.
Cultural, regulatory, environmental, political and economic (CREPE) conditions over the past decade are creating cross-industry solution spaces that require processes and technologies from both the Internet of Things (IoT), and Data Management and Analytics (DMA). These solution spaces are evolving into Sensor Analytics Ecosystems (SAE) that represent significant new opportunities for organizations of all types. Public Utilities throughout the world, providing electricity, natural gas and water, are pursuing SmartGrid initiatives that represent one of the more mature examples of SAE. We have s...
The security devil is always in the details of the attack: the ones you've endured, the ones you prepare yourself to fend off, and the ones that, you fear, will catch you completely unaware and defenseless. The Internet of Things (IoT) is nothing if not an endless proliferation of details. It's the vision of a world in which continuous Internet connectivity and addressability is embedded into a growing range of human artifacts, into the natural world, and even into our smartphones, appliances, and physical persons. In the IoT vision, every new "thing" - sensor, actuator, data source, data con...
The Internet of Things is tied together with a thin strand that is known as time. Coincidentally, at the core of nearly all data analytics is a timestamp. When working with time series data there are a few core principles that everyone should consider, especially across datasets where time is the common boundary. In his session at Internet of @ThingsExpo, Jim Scott, Director of Enterprise Strategy & Architecture at MapR Technologies, discussed single-value, geo-spatial, and log time series data. By focusing on enterprise applications and the data center, he will use OpenTSDB as an example t...
How do APIs and IoT relate? The answer is not as simple as merely adding an API on top of a dumb device, but rather about understanding the architectural patterns for implementing an IoT fabric. There are typically two or three trends: Exposing the device to a management framework Exposing that management framework to a business centric logic Exposing that business layer and data to end users. This last trend is the IoT stack, which involves a new shift in the separation of what stuff happens, where data lives and where the interface lies. For instance, it's a mix of architectural styles ...
An entirely new security model is needed for the Internet of Things, or is it? Can we save some old and tested controls for this new and different environment? In his session at @ThingsExpo, New York's at the Javits Center, Davi Ottenheimer, EMC Senior Director of Trust, reviewed hands-on lessons with IoT devices and reveal a new risk balance you might not expect. Davi Ottenheimer, EMC Senior Director of Trust, has more than nineteen years' experience managing global security operations and assessments, including a decade of leading incident response and digital forensics. He is co-author of t...
The Internet of Things will greatly expand the opportunities for data collection and new business models driven off of that data. In her session at @ThingsExpo, Esmeralda Swartz, CMO of MetraTech, discussed how for this to be effective you not only need to have infrastructure and operational models capable of utilizing this new phenomenon, but increasingly service providers will need to convince a skeptical public to participate. Get ready to show them the money!
The Internet of Things will put IT to its ultimate test by creating infinite new opportunities to digitize products and services, generate and analyze new data to improve customer satisfaction, and discover new ways to gain a competitive advantage across nearly every industry. In order to help corporate business units to capitalize on the rapidly evolving IoT opportunities, IT must stand up to a new set of challenges. In his session at @ThingsExpo, Jeff Kaplan, Managing Director of THINKstrategies, will examine why IT must finally fulfill its role in support of its SBUs or face a new round of...
One of the biggest challenges when developing connected devices is identifying user value and delivering it through successful user experiences. In his session at Internet of @ThingsExpo, Mike Kuniavsky, Principal Scientist, Innovation Services at PARC, described an IoT-specific approach to user experience design that combines approaches from interaction design, industrial design and service design to create experiences that go beyond simple connected gadgets to create lasting, multi-device experiences grounded in people's real needs and desires.
Enthusiasm for the Internet of Things has reached an all-time high. In 2013 alone, venture capitalists spent more than $1 billion dollars investing in the IoT space. With "smart" appliances and devices, IoT covers wearable smart devices, cloud services to hardware companies. Nest, a Google company, detects temperatures inside homes and automatically adjusts it by tracking its user's habit. These technologies are quickly developing and with it come challenges such as bridging infrastructure gaps, abiding by privacy concerns and making the concept a reality. These challenges can't be addressed w...
The Domain Name Service (DNS) is one of the most important components in networking infrastructure, enabling users and services to access applications by translating URLs (names) into IP addresses (numbers). Because every icon and URL and all embedded content on a website requires a DNS lookup loading complex sites necessitates hundreds of DNS queries. In addition, as more internet-enabled ‘Things' get connected, people will rely on DNS to name and find their fridges, toasters and toilets. According to a recent IDG Research Services Survey this rate of traffic will only grow. What's driving t...
Scott Jenson leads a project called The Physical Web within the Chrome team at Google. Project members are working to take the scalability and openness of the web and use it to talk to the exponentially exploding range of smart devices. Nearly every company today working on the IoT comes up with the same basic solution: use my server and you'll be fine. But if we really believe there will be trillions of these devices, that just can't scale. We need a system that is open a scalable and by using the URL as a basic building block, we open this up and get the same resilience that the web enjoys.
Connected devices and the Internet of Things are getting significant momentum in 2014. In his session at Internet of @ThingsExpo, Jim Hunter, Chief Scientist & Technology Evangelist at Greenwave Systems, examined three key elements that together will drive mass adoption of the IoT before the end of 2015. The first element is the recent advent of robust open source protocols (like AllJoyn and WebRTC) that facilitate M2M communication. The second is broad availability of flexible, cost-effective storage designed to handle the massive surge in back-end data in a world where timely analytics is e...
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 want to use their existing identities, but these will have credentials already that are (hopefully) i...
"Matrix is an ambitious open standard and implementation that's set up to break down the fragmentation problems that exist in IP messaging and VoIP communication," explained John Woolf, Technical Evangelist at Matrix, in this SYS-CON.tv interview at @ThingsExpo, held Nov 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA.
P2P RTC will impact the landscape of communications, shifting from traditional telephony style communications models to OTT (Over-The-Top) cloud assisted & PaaS (Platform as a Service) communication services. The P2P shift will impact many areas of our lives, from mobile communication, human interactive web services, RTC and telephony infrastructure, user federation, security and privacy implications, business costs, and scalability. In his session at @ThingsExpo, Robin Raymond, Chief Architect at Hookflash, will walk through the shifting landscape of traditional telephone and voice services ...
Explosive growth in connected devices. Enormous amounts of data for collection and analysis. Critical use of data for split-second decision making and actionable information. All three are factors in making the Internet of Things a reality. Yet, any one factor would have an IT organization pondering its infrastructure strategy. How should your organization enhance its IT framework to enable an Internet of Things implementation? In his session at Internet of @ThingsExpo, James Kirkland, Chief Architect for the Internet of Things and Intelligent Systems at Red Hat, described how to revolutioniz...
Bit6 today issued a challenge to the technology community implementing Web Real Time Communication (WebRTC). To leap beyond WebRTC’s significant limitations and fully leverage its underlying value to accelerate innovation, application developers need to consider the entire communications ecosystem.
The definition of IoT is not new, in fact it’s been around for over a decade. What has changed is the public's awareness that the technology we use on a daily basis has caught up on the vision of an always on, always connected world. If you look into the details of what comprises the IoT, you’ll see that it includes everything from cloud computing, Big Data analytics, “Things,” Web communication, applications, network, storage, etc. It is essentially including everything connected online from hardware to software, or as we like to say, it’s an Internet of many different things. The difference ...
Cloud Expo 2014 TV commercials will feature @ThingsExpo, which was launched in June, 2014 at New York City's Javits Center as the largest 'Internet of Things' event in the world.