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• ADF Business Components

  - by Arda Eralp

  ADF Business Components and JDeveloper simplify the development, delivery, and customization of business applications for the Java EE platform. With ADF Business Components, developers aren't required to write the application infrastructure code required by the typical Java EE application to: Connect to the database Retrieve data Lock database records Manage transactions   ADF Business Components addresses these tasks through its library of reusable software components and through the supporting design time facilities in JDeveloper. Most importantly, developers save time using ADF Business Components since the JDeveloper design time makes typical development tasks entirely declarative. In particular, JDeveloper supports declarative development with ADF Business Components to: Author and test business logic in components which automatically integrate with databases Reuse business logic through multiple SQL-based views of data, supporting different application tasks Access and update the views from browser, desktop, mobile, and web service clients Customize application functionality in layers without requiring modification of the delivered application The goal of ADF Business Components is to make the business services developer more productive.   ADF Business Components provides a foundation of Java classes that allow your business-tier application components to leverage the functionality provided in the following areas: Simplifying Data Access Design a data model for client displays, including only necessary data Include master-detail hierarchies of any complexity as part of the data model Implement end-user Query-by-Example data filtering without code Automatically coordinate data model changes with business services layer Automatically validate and save any changes to the database   Enforcing Business Domain Validation and Business Logic Declaratively enforce required fields, primary key uniqueness, data precision-scale, and foreign key references Easily capture and enforce both simple and complex business rules, programmatically or declaratively, with multilevel validation support Navigate relationships between business domain objects and enforce constraints related to compound components   Supporting Sophisticated UIs with Multipage Units of Work Automatically reflect changes made by business service application logic in the user interface Retrieve reference information from related tables, and automatically maintain the information when the user changes foreign-key values Simplify multistep web-based business transactions with automatic web-tier state management Handle images, video, sound, and documents without having to use code Synchronize pending data changes across multiple views of data Consistently apply prompts, tooltips, format masks, and error messages in any application Define custom metadata for any business components to support metadata-driven user interface or application functionality Add dynamic attributes at runtime to simplify per-row state management   Implementing High-Performance Service-Oriented Architecture Support highly functional web service interfaces for business integration without writing code Enforce best-practice interface-based programming style Simplify application security with automatic JAAS integration and audit maintenance "Write once, run anywhere": use the same business service as plain Java class, EJB session bean, or web service   Streamlining Application Customization Extend component functionality after delivery without modifying source code Globally substitute delivered components with extended ones without modifying the application   ADF Business Components implements the business service through the following set of cooperating components: Entity object An entity object represents a row in a database table and simplifies modifying its data by handling all data manipulation language (DML) operations for you. These are basically your 1 to 1 representation of a database table. Each table in the database will have 1 and only 1 EO. The EO contains the mapping between columns and attributes. EO's also contain the business logic and validation. These are you core data services. They are responsible for updating, inserting and deleting records. The Attributes tab displays the actual mapping between attributes and columns, the mapping has following fields: Name : contains the name of the attribute we expose in our data model. Type : defines the data type of the attribute in our application. Column : specifies the column to which we want to map the attribute with Column Type : contains the type of the column in the database   View object A view object represents a SQL query. You use the full power of the familiar SQL language to join, filter, sort, and aggregate data into exactly the shape required by the end-user task. The attributes in the View Objects are actually coming from the Entity Object. In the end the VO will generate a query but you basically build a VO by selecting which EO need to participate in the VO and which attributes of those EO you want to use. That's why you have the Entity Usage column so you can see the relation between VO and EO. In the query tab you can clearly see the query that will be generated for the VO. At this stage we don't need it and just use it for information purpose. In later stages we might use it. Application module An application module is the controller of your data layer. It is responsible for keeping hold of the transaction. It exposes the data model to the view layer. You expose the VO's through the Application Module. This is the abstraction of your data layer which you want to show to the outside word.It defines an updatable data model and top-level procedures and functions (called service methods) related to a logical unit of work related to an end-user task. While the base components handle all the common cases through built-in behavior, customization is always possible and the default behavior provided by the base components can be easily overridden or augmented. When you create EO's, a foreign key will be translated into an association in our model. It defines the type of relation and who is the master and child as well as how the visibility of the association looks like. A similar concept exists to identify relations between view objects. These are called view links. These are almost identical as association except that a view link is based upon attributes defined in the view object. It can also be based upon an association. Here's a short summary: Entity Objects: representations of tables Association: Relations between EO's. Representations of foreign keys View Objects: Logical model View Links: Relationships between view objects Application Model: interface to your application  

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• QuadTree: store only points, or regions?

  - by alekop

  I am developing a quadtree to keep track of moving objects for collision detection. Each object has a bounding shape, let's say they are all circles. (It's a 2D top-down game) I am unsure whether to store only the position of each object, or the whole bounding shape. If working with points, insertion and subdivision is easy, because objects will never span multiple nodes. On the other hand, a proximity query for an object may miss collisions, because it won't take the objects' dimensions into account. How to calculate the query region when you only have points? If working with regions, how to handle an object that spans multiple nodes? Should it be inserted in the nearest parent node that completely contains it, even if this exceeds the node's capacity? Thanks.

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• Passing data between engine layers

  - by spaceOwl

  I am building a software system (game engine with networking support ) that is made up of (roughly) these layers: Game Layer Messaging Layer Networking Layer Game related data is passed to the messaging layer (this could be anything that is game specific), where they are to be converted to network specific messages (which are then serialized to byte arrays). I'm looking for a way to be able to convert "game" data into "network" data, such that no strong coupling between these layers will exist. As it looks now, the Messaging layer sits between both layers (game and network) and "knows" both of them (it contains Converter objects that know how to translate between data objects of both layers back and forth). I am not sure this is the best solution. Is there a good design for passing objects between layers? I'd like to learn more about the different options.

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• Find Nearest Object

  - by ultifinitus

  I have a fairly sizable game engine created, and I'm adding some needed features, such as this, how do I find the nearest object from a list of points? In this case, I could simply use the Pythagorean theorem to find the distance, and check the results. I know I can't simply add x and y, because that's the distance to the object, if you only took right angle turns. However I'm wondering if there's something else I could do? I also have a collision system, where essentially I turn objects into smaller objects on a smaller grid, kind of like a minimap, and only if objects exist in the same gridspace do I check for collisions, I could do the same thing, only make the gridspace larger to check for closeness. (rather than checking every. single. object) however that would take additional setup in my base class and clutter up the already cluttered object. TL;DR Question: Is there something efficient and accurate that I can use to detect which object is closest, based on a list of points and sizes?

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• Optimizing hierarchical transform

  - by Geotarget

  I'm transforming objects in 3D space by transforming each vector with the object's 4x4 transform matrix. In order to achieve hierarchical transform, I transform the child by its own matrix, and then the child by the parent matrix. This becomes costly because objects deeper in the display tree have to be transformed by all the parent objects. This is what's happening, in summary: Root -- transform its verts by Root matrix Parent -- transform its verts by Parent, Root matrix Child -- transform its verts by Child, Parent, Root matrix Is there a faster way to transform vertices to achieve hierarchical transform? What If I first concatenated each transform matrix with the parent matrices, and then transform verts by that final resulting matrix, would that work and wouldn't that be faster? Root -- transform its verts by Root matrix Parent -- concat Parent, Root matrices, transform its verts by Concated matrix Child -- concat Child, Parent, Root matrices, transform its verts by Concated matrix

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• What would be a good game making engine supporting Vector images?

  - by Qqwy

  I want to create a simple platforming game, in which you are a square in a wonderful world. I would like this game to be able to be played in browsers. Basically I am searching for something similar to "Flixel", but with the following features: Support Vector Graphics Allow zooming/rotating objects without producing huge amounts of lag as soon as you are using more objects. (Because I want to rotate the map around the player) So in other words, preferably zoom the viewport/camera instead of the objects themselves. Does an engine like that exist?

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• World to Pixel Transformation

  - by D00d

  My objects have a location in world coordinates (basically 1.0f is a meter). If I simply draw my objects using their world coordinates, each meter will correspond to a pixel. Obviously that's not what I want. Now, I don't want to have to apply a transformation to each and every object's position when I draw them. As I happen to be using XNA, and spritebatch allows a Matrix to be passed in as an argument in it's begin method, I was wondering if there is a way to pass the World to Pixel transformation in there. Any suggestions? So far Matrix.CreateScale(new Vector3(zoom, zoom, 1)) puts the objects in their proper spot, but it also scales up the sprites. Is there a way to transform the position without enlarging the sprite? Thanks

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• EBS Applications Technology Group (ATG) Advisor Webcast December 2012

  - by LuciaC

  Invitation : Advisor Webcast December 2012 In December 2012 we have scheduled an Advisor Webcast, where we want to give you a closer look into the invalid objects in an E-Business Suite Environment. E-Business Suite - Troubleshooting invalid objectsAgenda : Introduction Activities that generate invalid objects EBS Architecture EBS Patching Concepts Troubleshooting Invalid Objects References EMEA Session : Tuesday December 11th, 2012 at 09:00 AM UK / 10:00 AM CET / 13:30 India / 17:00 Japan / 18:00 Australia Details & Registration : Doc ID 1501696.1Direct link to register in WebExUS Session : Wednesday December 12th, 2012 at 18:00 UK / 19:00 CET / 10:00 AM Pacific / 11:00 AM Mountain/ 01:00 PM Eastern Details & Registration : Doc ID 1501697.1Direct link to register in WebExIf you have any question about the schedules or if you have a suggestion for an Advisor Webcast to be planned in future, please send an E-Mail to Ruediger Ziegler.

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• Generic Handler vs Direct Reference

  - by JNF

  In a project where I'm working on the data access layer I'm trying to make a decision how to send data and objects to the next layer (and programmer). Is it better to tell him to reference my dll, OR should I build a generic handler and let him take the objects from there (i.e. json format) If I understand correctly, In case of 2. he would have to handle the objects on his own, whereas in case 1. he will have the entities I've built. Note: It is very probable that other people would need to take the same data, though, we're not up to that yet. Same question here - should I make it into a webservice, or have them access the handler?

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• Should Business Interfaces be part of the Model layer?

  - by Mik378

  In an oriented-services enterprise application, isn't it an antipattern to mix Service APIs (containing interface that external users depends on) with Model objects (entities, custom exceptions objects etc...) ? According to me, Services should only depends on Model layer but never mixed with it. In fact, my colleague told me that it doesn't make sense to separate it since client need both. (model and service interfaces) But I notice that everytime a client asks for some changes, like adding a new method in some interface (means a new service), Model layer has to be also delivered... Thus, client who has not interested by this "addition" is constrained to be concerned by this update of Model... and in a large enterprise application, this kind of delivery is known to be very risked... What is the best practice ? Separate services(only interfaces so) and model objects or mix it ?

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• F# - When do you use a class instead of a record when you do not want to use mutable fields?

  - by fairflow

  I'm imagining a situation where you are creating an F# module in a purely functional style. This means objects do not have mutable fields and are not modified in place. I'm assuming for simplicity that there is no need to use .NET objects or other kinds of objects. There are two possible ways of implementing an object-oriented kind of solution: the first is to use type classes and the second to use records which have fields of functional type, to implement methods. I imagine you'd use classes when you want to use inheritance but that otherwise records would be adequate, if perhaps clumsier to express. Or do you find classes more convenient than records in any case?

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• F# - When do you use a type class instead of a record when you do not want to use mutable fields?

  - by fairflow

  I'm imagining a situation where you are creating an F# module in a purely functional style. This means objects do not have mutable fields and are not modified in place. I'm assuming for simplicity that there is no need to use .NET objects or other kinds of objects. There are two possible ways of implementing an object-oriented kind of solution: the first is to use type classes and the second to use records which have fields of functional type, to implement methods. I imagine you'd use classes when you want to use inheritance but that otherwise records would be adequate, if perhaps clumsier to express. Or do you find classes more convenient than records in any case?

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• Orchestrating the Virtual Enterprise

  - by John Murphy

  During the American Industrial Revolution, the Ford Motor Company did it all. It turned raw materials into a showroom full of Model Ts. It owned a steel mill, a glass factory, and an automobile assembly line. The company was both self-sufficient and innovative and went on to become one of the largest and most profitable companies in the world. Nowadays, it's unusual for any business to follow this vertical integration model because its much harder to be best in class across such a wide a range of capabilities and services. Instead, businesses focus on their core competencies and outsource other business functions to specialized suppliers. They exchange vertical integration for collaboration. When done well, all parties benefit from this arrangement and the collaboration leads to the creation of an agile, lean and successful "virtual enterprise." Case in point: For Sun hardware, Oracle outsources most of its manufacturing and all of its logistics to third parties. These are vital activities, but ones where Oracle doesn't have a core competency, so we shift them to business partners who do. Within our enterprise, we always retain the core functions of product development, support, and most of the sales function, because that's what constitutes our core value to our customers. This is a perfect example of a virtual enterprise.  What are the implications of this? It means that we must exchange direct internal control for indirect external collaboration. This fundamentally changes the relative importance of different business processes, the boundaries of security and information sharing, and the relationship of the supply chain systems to the ERP. The challenge is that the systems required to support this virtual paradigm are still mired in "island enterprise" thinking. But help is at hand. Developments such as the Web, social networks, collaboration, and rules-based orchestration offer great potential to fundamentally re-architect supply chain systems to better support the virtual enterprise.  Supply Chain Management Systems in a Virtual Enterprise Historically enterprise software was constructed to automate the ERP - and then the supply chain systems extended the ERP. They were joined at the hip. In virtual enterprises, the supply chain system needs to be ERP agnostic, sitting above each of the ERPs that are distributed across the virtual enterprise - most of which are operating in other businesses. This is vital so that the supply chain system can manage the flow of material and the related information through the multiple enterprises. It has to have strong collaboration tools. It needs to be highly flexible. Users need to be able to see information that's coming from multiple sources and be able to react and respond to events across those sources.  Oracle Fusion Distributed Order Orchestration (DOO) is a perfect example of a supply chain system designed to operate in this virtual way. DOO embraces the idea that a company's fulfillment challenge is a distributed, multi-enterprise problem. It enables users to manage the process and the trading partners in a uniform way and deliver a consistent user experience while operating over a heterogeneous, virtual enterprise. This is a fundamental shift at the core of managing supply chains. It forces virtual enterprises to think architecturally about how best to construct their supply chain systems.  Case in point, almost everyone has ordered from Amazon.com at one time or another. Our orders are as likely to be fulfilled by third parties as they are by Amazon itself. To deliver the order promptly and efficiently, Amazon has to send it to the right fulfillment location and know the availability in that location. It needs to be able to track status of the fulfillment and deal with exceptions. As a virtual enterprise, Amazon's operations, using thousands of trading partners, requires a very different approach to fulfillment than the traditional 'take an order and ship it from your own warehouse' model. Amazon had no choice but to develop a complex, expensive and custom solution to tackle this problem as there used to be no product solution available. Now, other companies who want to follow similar models have a better off-the-shelf choice -- Oracle Distributed Order Orchestration (DOO).  Consider how another of our customers is using our distributed orchestration solution. This major airplane manufacturer has a highly complex business and interacts regularly with the U.S. Government and major airlines. It sits in the middle of an intricate supply chain and needed to improve visibility across its many different entities. Oracle Fusion DOO gives the company an orchestration mechanism so it could improve quality, speed, flexibility, and consistency without requiring an organ transplant of these highly complex legacy systems. Many retailers face the challenge of dealing with brick and mortar, Web, and reseller channels. They all need to be knitted together into a virtual enterprise experience that is consistent for their customers. When a large U.K. grocer with a strong brick and mortar retail operation added an online business, they turned to Oracle Fusion DOO to bring these entities together. Disturbing the Peace with Acquisitions Quite often a company's ERP system is disrupted when it acquires a new company. An acquisition can inject a new set of processes and systems -- or even introduce an entirely new business like Sun's hardware did at Oracle. This challenge has been a driver for some of our DOO customers. A large power management company is using Oracle Fusion DOO to provide the flexibility to rapidly integrate additional products and services into its central fulfillment operation. The Flip Side of Fulfillment Meanwhile, we haven't ignored similar challenges on the supply side of the equation. Specifically, how to manage complex supply in a flexible way when there are multiple trading parties involved? How to manage the supply to suppliers? How to manage critical components that need to merge in a tier two or tier three supply chain? By investing in supply orchestration solutions for the virtual enterprise, we plan to give users better visibility into their network of suppliers to help them drive down costs. We also think this technology and full orchestration process can be applied to the financial side of organizations. An example is transactions that flow through complex internal structures to minimize tax exposure. We can help companies manage those transactions effectively by thinking about the internal organization as a virtual enterprise and bringing the same solution set to this internal challenge.  The Clear Front Runner No other company is investing in solving the virtual enterprise supply chain issues like Oracle is. Oracle is in a unique position to become the gold standard in this market space. We have the infrastructure of Oracle technology. We already have an Oracle Fusion DOO application which embraces the best of what's required in this area. And we're absolutely committed to extending our Fusion solution to other use cases and delivering even more business value.

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• Is your team is a high-performing team?

  As a child I can remember looking out of the car window as my father drove along the Interstate in Florida while seeing prisoners wearing bright orange jump suits and prison guards keeping a watchful eye on them. The prisoners were taking part in a prison road gang. These road gangs were formed to help the state maintain the state highway infrastructure. The prisoner’s primary responsibilities are to pick up trash and debris from the roadway. This is a prime example of a work group or working group used by most prison systems in the United States. Work groups or working groups can be defined as a collection of individuals or entities working together to achieve a specific goal or accomplish a specific set of tasks. Typically these groups are only established for a short period of time and are dissolved once the desired outcome has been achieved. More often than not group members usually feel as though they are expendable to the group and some even dread that they are even in the group. "A team is a small number of people with complementary skills who are committed to a common purpose, performance goals, and approach for which they are mutually accountable." (Katzenbach and Smith, 1993) So how do you determine that a team is a high-performing team?  This can be determined by three base line criteria that include: consistently high quality output, the promotion of personal growth and well being of all team members, and most importantly the ability to learn and grow as a unit. Initially, a team can successfully create high-performing output without meeting all three criteria, however this will erode over time because team members will feel detached from the group or that they are not growing then the quality of the output will decline. High performing teams are similar to work groups because they both utilize a collection of individuals or entities to accomplish tasks. What distinguish a high-performing team from a work group are its characteristics. High-performing teams contain five core characteristics. These characteristics are what separate a group from a team. The five characteristics of a high-performing team include: Purpose, Performance Measures, People with Tasks and Relationship Skills, Process, and Preparation and Practice. A high-performing team is much more than a work group, and typically has a life cycle that can vary from team to team. The standard team lifecycle consists of five states and is comparable to a human life cycle. The five states of a high-performing team lifecycle include: Formulating, Storming, Normalizing, Performing, and Adjourning. The Formulating State of a team is first realized when the team members are first defined and roles are assigned to all members. This initial stage is very important because it can set the tone for the team and can ultimately determine its success or failure. In addition, this stage requires the team to have a strong leader because team members are normally unclear about specific roles, specific obstacles and goals that my lay ahead of them.  Finally, this stage is where most team members initially meet one another prior to working as a team unless the team members already know each other. The Storming State normally arrives directly after the formulation of a new team because there are still a lot of unknowns amongst the newly formed assembly. As a general rule most of the parties involved in the team are still getting used to the workload, pace of work, deadlines and the validity of various tasks that need to be performed by the group.  In this state everything is questioned because there are so many unknowns. Items commonly questioned include the credentials of others on the team, the actual validity of a project, and the leadership abilities of the team leader.  This can be exemplified by looking at the interactions between animals when they first meet.  If we look at a scenario where two people are walking directly toward each other with their dogs. The dogs will automatically enter the Storming State because they do not know the other dog. Typically in this situation, they attempt to define which is more dominating via play or fighting depending on how the dogs interact with each other. Once dominance has been defined and accepted by both dogs then they will either want to play or leave depending on how the dogs interacted and other environmental variables. Once the Storming State has been realized then the Normalizing State takes over. This state is entered by a team once all the questions of the Storming State have been answered and the team has been tested by a few tasks or projects.  Typically, participants in the team are filled with energy, and comradery, and a strong alliance with team goals and objectives.  A high school football team is a perfect example of the Normalizing State when they start their season.  The player positions have been assigned, the depth chart has been filled and everyone is focused on winning each game. All of the players encourage and expect each other to perform at the best of their abilities and are united by competition from other teams. The Performing State is achieved by a team when its history, working habits, and culture solidify the team as one working unit. In this state team members can anticipate specific behaviors, attitudes, reactions, and challenges are seen as opportunities and not problems. Additionally, each team member knows their role in the team’s success, and the roles of others. This is the most productive state of a group and is where all the time invested working together really pays off. If you look at an Olympic figure skating team skate you can easily see how the time spent working together benefits their performance. They skate as one unit even though it is comprised of two skaters. Each skater has their routine completely memorized as well as their partners. This allows them to anticipate each other’s moves on the ice makes their skating look effortless. The final state of a team is the Adjourning State. This state is where accomplishments by the team and each individual team member are recognized. Additionally, this state also allows for reflection of the interactions between team members, work accomplished and challenges that were faced. Finally, the team celebrates the challenges they have faced and overcome as a unit. Currently in the workplace teams are divided into two different types: Co-located and Distributed Teams. Co-located teams defined as the traditional group of people working together in an office, according to Andy Singleton of Assembla. This traditional type of a team has dominated business in the past due to inadequate technology, which forced workers to primarily interact with one another via face to face meetings.  Team meetings are primarily lead by the person with the highest status in the company. Having personally, participated in meetings of this type, usually a select few of the team members dominate the flow of communication which reduces the input of others in group discussions. Since discussions are dominated by a select few individuals the discussions and group discussion are skewed in favor of the individuals who communicate the most in meetings. In addition, Team members might not give their full opinions on a topic of discussion in part not to offend or create controversy amongst the team and can alter decision made in meetings towards those of the opinions of the dominating team members. Distributed teams are by definition spread across an area or subdivided into separate sections. That is exactly what distributed teams when compared to a more traditional team. It is common place for distributed teams to have team members across town, in the next state, across the country and even with the advances in technology over the last 20 year across the world. These teams allow for more diversity compared to the other type of teams because they allow for more flexibility regarding location. A team could consist of a 30 year old male Italian project manager from New York, a 50 year old female Hispanic from California and a collection of programmers from India because technology allows them to communicate as if they were standing next to one another.  In addition, distributed team members consult with more team members prior to making decisions compared to traditional teams, and take longer to come to decisions due to the changes in time zones and cultural events. However, team members feel more empowered to speak out when they do not agree with the team and to notify others of potential issues regarding the work that the team is doing. Virtual teams which are a subset of the distributed team type is changing organizational strategies due to the fact that a team can now in essence be working 24 hrs a day because of utilizing employees in various time zones and locations.  A primary example of this is with customer services departments, a company can have multiple call centers spread across multiple time zones allowing them to appear to be open 24 hours a day while all a employees work from 9AM to 5 PM every day. Virtual teams also allow human resources departments to go after the best talent for the company regardless of where the potential employee works because they will be a part of a virtual team all that is need is the proper technology to be setup to allow everyone to communicate. In addition to allowing employees to work from home, the company can save space and resources by not having to provide a desk for every team member. In fact, those team members that randomly come into the office can actually share one desk amongst multiple people. This is definitely a cost cutting plus given the current state of the economy. One thing that can turn a team into a high-performing team is leadership. High-performing team leaders need to focus on investing in ongoing personal development, provide team members with direction, structure, and resources needed to accomplish their work, make the right interventions at the right time, and help the team manage boundaries between the team and various external parties involved in the teams work. A team leader needs to invest in ongoing personal development in order to effectively manage their team. People have said that attitude is everything; this is very true about leaders and leadership. A team takes on the attitudes and behaviors of its leaders. This can potentially harm the team and the team’s output. Leaders must concentrate on self-awareness, and understanding their team’s group dynamics to fully understand how to lead them. In addition, always learning new leadership techniques from other effective leaders is also very beneficial. Providing team members with direction, structure, and resources that they need to accomplish their work collectively sounds easy, but it is not.  Leaders need to be able to effectively communicate with their team on how their work helps the company reach for its organizational vision. Conversely, the leader needs to allow his team to work autonomously within specific guidelines to turn the company’s vision into a reality.  This being said the team must be appropriately staffed according to the size of the team’s tasks and their complexity. These tasks should be clear, and be meaningful to the company’s objectives and allow for feedback to be exchanged with the leader and the team member and the leader and upper management. Now if the team is properly staffed, and has a clear and full understanding of what is to be done; the company also must supply the workers with the proper tools to achieve the tasks that they are asked to do. No one should be asked to dig a hole without being given a shovel.  Finally, leaders must reward their team members for accomplishments that they achieve. Awards could range from just a simple congratulatory email, a party to close the completion of a large project, or other monetary rewards. Managing boundaries is very important for team leaders because it can alter attitudes of team members and can add undue stress to the team which will force them to loose focus on the tasks at hand for the group. Team leaders should promote communication between team members so that burdens are shared amongst the team and solutions can be derived from hearing the opinions of multiple sources. This also reinforces team camaraderie and working as a unit. Team leaders must manage the type and timing of interventions as to not create an even bigger mess within the team. Poorly timed interventions can really deflate team members and make them question themselves. This could really increase further and undue interventions by the team leader. Typically, the best time for interventions is when the team is just starting to form so that all unproductive behaviors are removed from the team and that it can retain focus on its agenda. If an intervention is effectively executed the team will feel energized about the work that they are doing, promote communication and interaction amongst the group and improve moral overall. High-performing teams are very import to organizations because they consistently produce high quality output and develop a collective purpose for their work. This drive to succeed allows team members to utilize specific talents allowing for growth in these areas.  In addition, these team members usually take on a sense of ownership with their projects and feel that the other team members are irreplaceable. References: http://blog.assembla.com/assemblablog/tabid/12618/bid/3127/Three-ways-to-organize-your-team-co-located-outsourced-or-global.aspx Katzenbach, J.R. & Smith, D.K. (1993). The Wisdom of Teams: Creating the High-performance Organization. Boston: Harvard Business School.

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• C#/.NET Fundamentals: Choosing the Right Collection Class

  - by James Michael Hare

  The .NET Base Class Library (BCL) has a wide array of collection classes at your disposal which make it easy to manage collections of objects. While it's great to have so many classes available, it can be daunting to choose the right collection to use for any given situation. As hard as it may be, choosing the right collection can be absolutely key to the performance and maintainability of your application! This post will look at breaking down any confusion between each collection and the situations in which they excel. We will be spending most of our time looking at the System.Collections.Generic namespace, which is the recommended set of collections. The Generic Collections: System.Collections.Generic namespace The generic collections were introduced in .NET 2.0 in the System.Collections.Generic namespace. This is the main body of collections you should tend to focus on first, as they will tend to suit 99% of your needs right up front. It is important to note that the generic collections are unsynchronized. This decision was made for performance reasons because depending on how you are using the collections its completely possible that synchronization may not be required or may be needed on a higher level than simple method-level synchronization. Furthermore, concurrent read access (all writes done at beginning and never again) is always safe, but for concurrent mixed access you should either synchronize the collection or use one of the concurrent collections. So let's look at each of the collections in turn and its various pros and cons, at the end we'll summarize with a table to help make it easier to compare and contrast the different collections. The Associative Collection Classes Associative collections store a value in the collection by providing a key that is used to add/remove/lookup the item. Hence, the container associates the value with the key. These collections are most useful when you need to lookup/manipulate a collection using a key value. For example, if you wanted to look up an order in a collection of orders by an order id, you might have an associative collection where they key is the order id and the value is the order. The Dictionary<TKey,TVale> is probably the most used associative container class. The Dictionary<TKey,TValue> is the fastest class for associative lookups/inserts/deletes because it uses a hash table under the covers. Because the keys are hashed, the key type should correctly implement GetHashCode() and Equals() appropriately or you should provide an external IEqualityComparer to the dictionary on construction. The insert/delete/lookup time of items in the dictionary is amortized constant time - O(1) - which means no matter how big the dictionary gets, the time it takes to find something remains relatively constant. This is highly desirable for high-speed lookups. The only downside is that the dictionary, by nature of using a hash table, is unordered, so you cannot easily traverse the items in a Dictionary in order. The SortedDictionary<TKey,TValue> is similar to the Dictionary<TKey,TValue> in usage but very different in implementation. The SortedDictionary<TKey,TValye> uses a binary tree under the covers to maintain the items in order by the key. As a consequence of sorting, the type used for the key must correctly implement IComparable<TKey> so that the keys can be correctly sorted. The sorted dictionary trades a little bit of lookup time for the ability to maintain the items in order, thus insert/delete/lookup times in a sorted dictionary are logarithmic - O(log n). Generally speaking, with logarithmic time, you can double the size of the collection and it only has to perform one extra comparison to find the item. Use the SortedDictionary<TKey,TValue> when you want fast lookups but also want to be able to maintain the collection in order by the key. The SortedList<TKey,TValue> is the other ordered associative container class in the generic containers. Once again SortedList<TKey,TValue>, like SortedDictionary<TKey,TValue>, uses a key to sort key-value pairs. Unlike SortedDictionary, however, items in a SortedList are stored as an ordered array of items. This means that insertions and deletions are linear - O(n) - because deleting or adding an item may involve shifting all items up or down in the list. Lookup time, however is O(log n) because the SortedList can use a binary search to find any item in the list by its key. So why would you ever want to do this? Well, the answer is that if you are going to load the SortedList up-front, the insertions will be slower, but because array indexing is faster than following object links, lookups are marginally faster than a SortedDictionary. Once again I'd use this in situations where you want fast lookups and want to maintain the collection in order by the key, and where insertions and deletions are rare. The Non-Associative Containers The other container classes are non-associative. They don't use keys to manipulate the collection but rely on the object itself being stored or some other means (such as index) to manipulate the collection. The List<T> is a basic contiguous storage container. Some people may call this a vector or dynamic array. Essentially it is an array of items that grow once its current capacity is exceeded. Because the items are stored contiguously as an array, you can access items in the List<T> by index very quickly. However inserting and removing in the beginning or middle of the List<T> are very costly because you must shift all the items up or down as you delete or insert respectively. However, adding and removing at the end of a List<T> is an amortized constant operation - O(1). Typically List<T> is the standard go-to collection when you don't have any other constraints, and typically we favor a List<T> even over arrays unless we are sure the size will remain absolutely fixed. The LinkedList<T> is a basic implementation of a doubly-linked list. This means that you can add or remove items in the middle of a linked list very quickly (because there's no items to move up or down in contiguous memory), but you also lose the ability to index items by position quickly. Most of the time we tend to favor List<T> over LinkedList<T> unless you are doing a lot of adding and removing from the collection, in which case a LinkedList<T> may make more sense. The HashSet<T> is an unordered collection of unique items. This means that the collection cannot have duplicates and no order is maintained. Logically, this is very similar to having a Dictionary<TKey,TValue> where the TKey and TValue both refer to the same object. This collection is very useful for maintaining a collection of items you wish to check membership against. For example, if you receive an order for a given vendor code, you may want to check to make sure the vendor code belongs to the set of vendor codes you handle. In these cases a HashSet<T> is useful for super-quick lookups where order is not important. Once again, like in Dictionary, the type T should have a valid implementation of GetHashCode() and Equals(), or you should provide an appropriate IEqualityComparer<T> to the HashSet<T> on construction. The SortedSet<T> is to HashSet<T> what the SortedDictionary<TKey,TValue> is to Dictionary<TKey,TValue>. That is, the SortedSet<T> is a binary tree where the key and value are the same object. This once again means that adding/removing/lookups are logarithmic - O(log n) - but you gain the ability to iterate over the items in order. For this collection to be effective, type T must implement IComparable<T> or you need to supply an external IComparer<T>. Finally, the Stack<T> and Queue<T> are two very specific collections that allow you to handle a sequential collection of objects in very specific ways. The Stack<T> is a last-in-first-out (LIFO) container where items are added and removed from the top of the stack. Typically this is useful in situations where you want to stack actions and then be able to undo those actions in reverse order as needed. The Queue<T> on the other hand is a first-in-first-out container which adds items at the end of the queue and removes items from the front. This is useful for situations where you need to process items in the order in which they came, such as a print spooler or waiting lines. So that's the basic collections. Let's summarize what we've learned in a quick reference table.  Collection Ordered? Contiguous Storage? Direct Access? Lookup Efficiency Manipulate Efficiency Notes Dictionary No Yes Via Key Key: O(1) O(1) Best for high performance lookups. SortedDictionary Yes No Via Key Key: O(log n) O(log n) Compromise of Dictionary speed and ordering, uses binary search tree. SortedList Yes Yes Via Key Key: O(log n) O(n) Very similar to SortedDictionary, except tree is implemented in an array, so has faster lookup on preloaded data, but slower loads. List No Yes Via Index Index: O(1) Value: O(n) O(n) Best for smaller lists where direct access required and no ordering. LinkedList No No No Value: O(n) O(1) Best for lists where inserting/deleting in middle is common and no direct access required. HashSet No Yes Via Key Key: O(1) O(1) Unique unordered collection, like a Dictionary except key and value are same object. SortedSet Yes No Via Key Key: O(log n) O(log n) Unique ordered collection, like SortedDictionary except key and value are same object. Stack No Yes Only Top Top: O(1) O(1)* Essentially same as List<T> except only process as LIFO Queue No Yes Only Front Front: O(1) O(1) Essentially same as List<T> except only process as FIFO   The Original Collections: System.Collections namespace The original collection classes are largely considered deprecated by developers and by Microsoft itself. In fact they indicate that for the most part you should always favor the generic or concurrent collections, and only use the original collections when you are dealing with legacy .NET code. Because these collections are out of vogue, let's just briefly mention the original collection and their generic equivalents: ArrayList A dynamic, contiguous collection of objects. Favor the generic collection List<T> instead. Hashtable Associative, unordered collection of key-value pairs of objects. Favor the generic collection Dictionary<TKey,TValue> instead. Queue First-in-first-out (FIFO) collection of objects. Favor the generic collection Queue<T> instead. SortedList Associative, ordered collection of key-value pairs of objects. Favor the generic collection SortedList<T> instead. Stack Last-in-first-out (LIFO) collection of objects. Favor the generic collection Stack<T> instead. In general, the older collections are non-type-safe and in some cases less performant than their generic counterparts. Once again, the only reason you should fall back on these older collections is for backward compatibility with legacy code and libraries only. The Concurrent Collections: System.Collections.Concurrent namespace The concurrent collections are new as of .NET 4.0 and are included in the System.Collections.Concurrent namespace. These collections are optimized for use in situations where multi-threaded read and write access of a collection is desired. The concurrent queue, stack, and dictionary work much as you'd expect. The bag and blocking collection are more unique. Below is the summary of each with a link to a blog post I did on each of them. ConcurrentQueue Thread-safe version of a queue (FIFO). For more information see: C#/.NET Little Wonders: The ConcurrentStack and ConcurrentQueue ConcurrentStack Thread-safe version of a stack (LIFO). For more information see: C#/.NET Little Wonders: The ConcurrentStack and ConcurrentQueue ConcurrentBag Thread-safe unordered collection of objects. Optimized for situations where a thread may be bother reader and writer. For more information see: C#/.NET Little Wonders: The ConcurrentBag and BlockingCollection ConcurrentDictionary Thread-safe version of a dictionary. Optimized for multiple readers (allows multiple readers under same lock). For more information see C#/.NET Little Wonders: The ConcurrentDictionary BlockingCollection Wrapper collection that implement producers & consumers paradigm. Readers can block until items are available to read. Writers can block until space is available to write (if bounded). For more information see C#/.NET Little Wonders: The ConcurrentBag and BlockingCollection Summary The .NET BCL has lots of collections built in to help you store and manipulate collections of data. Understanding how these collections work and knowing in which situations each container is best is one of the key skills necessary to build more performant code. Choosing the wrong collection for the job can make your code much slower or even harder to maintain if you choose one that doesn’t perform as well or otherwise doesn’t exactly fit the situation. Remember to avoid the original collections and stick with the generic collections.  If you need concurrent access, you can use the generic collections if the data is read-only, or consider the concurrent collections for mixed-access if you are running on .NET 4.0 or higher.   Tweet Technorati Tags: C#,.NET,Collecitons,Generic,Concurrent,Dictionary,List,Stack,Queue,SortedList,SortedDictionary,HashSet,SortedSet

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• What's up with OCFS2?

  - by wcoekaer

  On Linux there are many filesystem choices and even from Oracle we provide a number of filesystems, all with their own advantages and use cases. Customers often confuse ACFS with OCFS or OCFS2 which then causes assumptions to be made such as one replacing the other etc... I thought it would be good to write up a summary of how OCFS2 got to where it is, what we're up to still, how it is different from other options and how this really is a cool native Linux cluster filesystem that we worked on for many years and is still widely used. Work on a cluster filesystem at Oracle started many years ago, in the early 2000's when the Oracle Database Cluster development team wrote a cluster filesystem for Windows that was primarily focused on providing an alternative to raw disk devices and help customers with the deployment of Oracle Real Application Cluster (RAC). Oracle RAC is a cluster technology that lets us make a cluster of Oracle Database servers look like one big database. The RDBMS runs on many nodes and they all work on the same data. It's a Shared Disk database design. There are many advantages doing this but I will not go into detail as that is not the purpose of my write up. Suffice it to say that Oracle RAC expects all the database data to be visible in a consistent, coherent way, across all the nodes in the cluster. To do that, there were/are a few options : 1) use raw disk devices that are shared, through SCSI, FC, or iSCSI 2) use a network filesystem (NFS) 3) use a cluster filesystem(CFS) which basically gives you a filesystem that's coherent across all nodes using shared disks. It is sort of (but not quite) combining option 1 and 2 except that you don't do network access to the files, the files are effectively locally visible as if it was a local filesystem. So OCFS (Oracle Cluster FileSystem) on Windows was born. Since Linux was becoming a very important and popular platform, we decided that we would also make this available on Linux and thus the porting of OCFS/Windows started. The first version of OCFS was really primarily focused on replacing the use of Raw devices with a simple filesystem that lets you create files and provide direct IO to these files to get basically native raw disk performance. The filesystem was not designed to be fully POSIX compliant and it did not have any where near good/decent performance for regular file create/delete/access operations. Cache coherency was easy since it was basically always direct IO down to the disk device and this ensured that any time one issues a write() command it would go directly down to the disk, and not return until the write() was completed. Same for read() any sort of read from a datafile would be a read() operation that went all the way to disk and return. We did not cache any data when it came down to Oracle data files. So while OCFS worked well for that, since it did not have much of a normal filesystem feel, it was not something that could be submitted to the kernel mail list for inclusion into Linux as another native linux filesystem (setting aside the Windows porting code ...) it did its job well, it was very easy to configure, node membership was simple, locking was disk based (so very slow but it existed), you could create regular files and do regular filesystem operations to a certain extend but anything that was not database data file related was just not very useful in general. Logfiles ok, standard filesystem use, not so much. Up to this point, all the work was done, at Oracle, by Oracle developers. Once OCFS (1) was out for a while and there was a lot of use in the database RAC world, many customers wanted to do more and were asking for features that you'd expect in a normal native filesystem, a real "general purposes cluster filesystem". So the team sat down and basically started from scratch to implement what's now known as OCFS2 (Oracle Cluster FileSystem release 2). Some basic criteria were : Design it with a real Distributed Lock Manager and use the network for lock negotiation instead of the disk Make it a Linux native filesystem instead of a native shim layer and a portable core Support standard Posix compliancy and be fully cache coherent with all operations Support all the filesystem features Linux offers (ACL, extended Attributes, quotas, sparse files,...) Be modern, support large files, 32/64bit, journaling, data ordered journaling, endian neutral, we can mount on both endian /cross architecture,.. Needless to say, this was a huge development effort that took many years to complete. A few big milestones happened along the way... OCFS2 was development in the open, we did not have a private tree that we worked on without external code review from the Linux Filesystem maintainers, great folks like Christopher Hellwig reviewed the code regularly to make sure we were not doing anything out of line, we submitted the code for review on lkml a number of times to see if we were getting close for it to be included into the mainline kernel. Using this development model is standard practice for anyone that wants to write code that goes into the kernel and having any chance of doing so without a complete rewrite or.. shall I say flamefest when submitted. It saved us a tremendous amount of time by not having to re-fit code for it to be in a Linus acceptable state. Some other filesystems that were trying to get into the kernel that didn't follow an open development model had a lot harder time and a lot harsher criticism. March 2006, when Linus released 2.6.16, OCFS2 officially became part of the mainline kernel, it was accepted a little earlier in the release candidates but in 2.6.16. OCFS2 became officially part of the mainline Linux kernel tree as one of the many filesystems. It was the first cluster filesystem to make it into the kernel tree. Our hope was that it would then end up getting picked up by the distribution vendors to make it easy for everyone to have access to a CFS. Today the source code for OCFS2 is approximately 85000 lines of code. We made OCFS2 production with full support for customers that ran Oracle database on Linux, no extra or separate support contract needed. OCFS2 1.0.0 started being built for RHEL4 for x86, x86-64, ppc, s390x and ia64. For RHEL5 starting with OCFS2 1.2. SuSE was very interested in high availability and clustering and decided to build and include OCFS2 with SLES9 for their customers and was, next to Oracle, the main contributor to the filesystem for both new features and bug fixes. Source code was always available even prior to inclusion into mainline and as of 2.6.16, source code was just part of a Linux kernel download from kernel.org, which it still is, today. So the latest OCFS2 code is always the upstream mainline Linux kernel. OCFS2 is the cluster filesystem used in Oracle VM 2 and Oracle VM 3 as the virtual disk repository filesystem. Since the filesystem is in the Linux kernel it's released under the GPL v2 The release model has always been that new feature development happened in the mainline kernel and we then built consistent, well tested, snapshots that had versions, 1.2, 1.4, 1.6, 1.8. But these releases were effectively just snapshots in time that were tested for stability and release quality. OCFS2 is very easy to use, there's a simple text file that contains the node information (hostname, node number, cluster name) and a file that contains the cluster heartbeat timeouts. It is very small, and very efficient. As Sunil Mushran wrote in the manual : OCFS2 is an efficient, easily configured, quickly installed, fully integrated and compatible, feature-rich, architecture and endian neutral, cache coherent, ordered data journaling, POSIX-compliant, shared disk cluster file system. Here is a list of some of the important features that are included : Variable Block and Cluster sizes Supports block sizes ranging from 512 bytes to 4 KB and cluster sizes ranging from 4 KB to 1 MB (increments in power of 2). Extent-based Allocations Tracks the allocated space in ranges of clusters making it especially efficient for storing very large files. Optimized Allocations Supports sparse files, inline-data, unwritten extents, hole punching and allocation reservation for higher performance and efficient storage. File Cloning/snapshots REFLINK is a feature which introduces copy-on-write clones of files in a cluster coherent way. Indexed Directories Allows efficient access to millions of objects in a directory. Metadata Checksums Detects silent corruption in inodes and directories. Extended Attributes Supports attaching an unlimited number of name:value pairs to the file system objects like regular files, directories, symbolic links, etc. Advanced Security Supports POSIX ACLs and SELinux in addition to the traditional file access permission model. Quotas Supports user and group quotas. Journaling Supports both ordered and writeback data journaling modes to provide file system consistency in the event of power failure or system crash. Endian and Architecture neutral Supports a cluster of nodes with mixed architectures. Allows concurrent mounts on nodes running 32-bit and 64-bit, little-endian (x86, x86_64, ia64) and big-endian (ppc64) architectures. In-built Cluster-stack with DLM Includes an easy to configure, in-kernel cluster-stack with a distributed lock manager. Buffered, Direct, Asynchronous, Splice and Memory Mapped I/Os Supports all modes of I/Os for maximum flexibility and performance. Comprehensive Tools Support Provides a familiar EXT3-style tool-set that uses similar parameters for ease-of-use. The filesystem was distributed for Linux distributions in separate RPM form and this had to be built for every single kernel errata release or every updated kernel provided by the vendor. We provided builds from Oracle for Oracle Linux and all kernels released by Oracle and for Red Hat Enterprise Linux. SuSE provided the modules directly for every kernel they shipped. With the introduction of the Unbreakable Enterprise Kernel for Oracle Linux and our interest in reducing the overhead of building filesystem modules for every minor release, we decide to make OCFS2 available as part of UEK. There was no more need for separate kernel modules, everything was built-in and a kernel upgrade automatically updated the filesystem, as it should. UEK allowed us to not having to backport new upstream filesystem code into an older kernel version, backporting features into older versions introduces risk and requires extra testing because the code is basically partially rewritten. The UEK model works really well for continuing to provide OCFS2 without that extra overhead. Because the RHEL kernel did not contain OCFS2 as a kernel module (it is in the source tree but it is not built by the vendor in kernel module form) we stopped adding the extra packages to Oracle Linux and its RHEL compatible kernel and for RHEL. Oracle Linux customers/users obviously get OCFS2 included as part of the Unbreakable Enterprise Kernel, SuSE customers get it by SuSE distributed with SLES and Red Hat can decide to distribute OCFS2 to their customers if they chose to as it's just a matter of compiling the module and making it available. OCFS2 today, in the mainline kernel is pretty much feature complete in terms of integration with every filesystem feature Linux offers and it is still actively maintained with Joel Becker being the primary maintainer. Since we use OCFS2 as part of Oracle VM, we continue to look at interesting new functionality to add, REFLINK was a good example, and as such we continue to enhance the filesystem where it makes sense. Bugfixes and any sort of code that goes into the mainline Linux kernel that affects filesystems, automatically also modifies OCFS2 so it's in kernel, actively maintained but not a lot of new development happening at this time. We continue to fully support OCFS2 as part of Oracle Linux and the Unbreakable Enterprise Kernel and other vendors make their own decisions on support as it's really a Linux cluster filesystem now more than something that we provide to customers. It really just is part of Linux like EXT3 or BTRFS etc, the OS distribution vendors decide. Do not confuse OCFS2 with ACFS (ASM cluster Filesystem) also known as Oracle Cloud Filesystem. ACFS is a filesystem that's provided by Oracle on various OS platforms and really integrates into Oracle ASM (Automatic Storage Management). It's a very powerful Cluster Filesystem but it's not distributed as part of the Operating System, it's distributed with the Oracle Database product and installs with and lives inside Oracle ASM. ACFS obviously is fully supported on Linux (Oracle Linux, Red Hat Enterprise Linux) but OCFS2 independently as a native Linux filesystem is also, and continues to also be supported. ACFS is very much tied into the Oracle RDBMS, OCFS2 is just a standard native Linux filesystem with no ties into Oracle products. Customers running the Oracle database and ASM really should consider using ACFS as it also provides storage/clustered volume management. Customers wanting to use a simple, easy to use generic Linux cluster filesystem should consider using OCFS2. To learn more about OCFS2 in detail, you can find good documentation on http://oss.oracle.com/projects/ocfs2 in the Documentation area, or get the latest mainline kernel from http://kernel.org and read the source. One final, unrelated note - since I am not always able to publicly answer or respond to comments, I do not want to selectively publish comments from readers. Sometimes I forget to publish comments, sometime I publish them and sometimes I would publish them but if for some reason I cannot publicly comment on them, it becomes a very one-sided stream. So for now I am going to not publish comments from anyone, to be fair to all sides. You are always welcome to email me and I will do my best to respond to technical questions, questions about strategy or direction are sometimes not possible to answer for obvious reasons.

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• CodePlex Daily Summary for Sunday, February 06, 2011

  CodePlex Daily Summary for Sunday, February 06, 2011Popular ReleasesMVVM Light Toolkit: MVVM Light Toolkit V3 SP1 (4): There was a small issue with the previous release that caused errors when installing the templates in VS10 Express. This release corrects the error. Only use this if you encountered issues when installing the previous release. No changes in the binaries.Finestra Virtual Desktops: 1.0: Finally the version 1.0 release! Sorry for the long delay since the last release, but I think that you'll find this release to be really smooth, really stable, and a really great enhancement to Windows. New features include: Windows 7 taskbar integration Major performance and usability improvements Redesigned look and feel New name: Finestra Better automatic updating Much faster full-screen switcher Fixes Windows 7 hotkey collisions by default Updated installerEnhSim: EnhSim 2.3.4 ALPHA: 2.3.3 ALPHAThis release supports WoW patch 4.06 at level 85 To use this release, you must have the Microsoft Visual C++ 2010 Redistributable Package installed. This can be downloaded from http://www.microsoft.com/downloads/en/details.aspx?FamilyID=A7B7A05E-6DE6-4D3A-A423-37BF0912DB84 To use the GUI you must have the .NET 4.0 Framework installed. This can be downloaded from http://www.microsoft.com/downloads/en/details.aspx?FamilyID=9cfb2d51-5ff4-4491-b0e5-b386f32c0992 - Updated Unheeded ...Nuclex Framework: R1323: This release is a pure XNA 4.0 release that no longer includes any XNA 3.1 binaries or projects. All x86 assemblies have been compiled targeting the .NET 4.0 Client Profile. Requires either Visual C# 2010 Express or Visual Studio 2010, both with XNA Game Studio 4.0. 3rd party libraries needed to compile and run the source code are included, so everything will compile out of the box. Changes: - Thanks to a generous contribution by Adrian Tsai, the TrueType importer now accepts standard Windo...Community Forums NNTP bridge: Community Forums NNTP Bridge V43: Release of the Community Forums NNTP Bridge to access the social and anwsers MS forums with a single, open source NNTP bridge. This release has added some features / bugfixes: Bugfix: Now supporting multi-line headers in all headers ;) / Thanks to Kai Schätzl for reporting this! Debug output optimized / Added a "Copy to clipboard" button in the debug windowFacebook C# SDK: 5.0.2 (BETA): PLEASE TAKE A FEW MINUTES TO GIVE US SOME FEEDBACK: Facebook C# SDK Survey This is third BETA release of the version 5 branch of the Facebook C# SDK. Remember this is a BETA build. Some things may change or not work exactly as planned. We are absolutely looking for feedback on this release to help us improve the final 5.X.X release. This release contains some breaking changes. Particularly with authentication. After spending time reviewing the trouble areas that people are having using th...ASP.NET MVC SiteMap provider: MvcSiteMapProvider 3.0.0 for MVC3: Using NuGet?MvcSiteMapProvider is also listed in the NuGet feed. Learn more... Like the project? Consider a donation!Donate via PayPal via PayPal. ChangelogTargeting ASP.NET MVC 3 and .NET 4.0 Additional UpdatePriority options for generating XML sitemaps Allow to specify target on SiteMapTitleAttribute One action with multiple routes and breadcrumbs Medium Trust optimizations Create SiteMapTitleAttribute for setting parent title IntelliSense for your sitemap with MvcSiteMapSchem...Rawr: Rawr 4.0.18 Beta: Rawr is now web-based. The link to use Rawr4 is: http://elitistjerks.com/rawr.phpThis is the Cataclysm Beta Release. More details can be found at the following link http://rawr.codeplex.com/Thread/View.aspx?ThreadId=237262 As of the 4.0.16 release, you can now also begin using the new Downloadable WPF version of Rawr!This is a pre-alpha release of the WPF version, there are likely to be a lot of issues. If you have a problem, please follow the Posting Guidelines and put it into the Issue Trac...patterns & practices SharePoint Guidance: SharePoint Guidance 2010 Hands On Lab: SharePoint Guidance 2010 Hands On Lab consists of six labs: one for logging, one for service location, and four for application setting manager. Each lab takes about 20 minutes to walk through. Each lab consists of a PDF document. You can go through the steps in the doc to create solution and then build/deploy the solution and run the lab. For those of you who wants to save the time, we included the final solution so you can just build/deploy the solution and run the lab.Value Injecter - object(s) to -> object mapper: 2.3: it lets you define your own convention-based matching algorithms (ValueInjections) in order to match up (inject) source values to destination values. inject from multiple sources in one InjectFrom added ConventionInjectionTweetSharp: TweetSharp v2.0.0.0 - Preview 10: Documentation for this release may be found at http://tweetsharp.codeplex.com/wikipage?title=UserGuide&referringTitle=Documentation. Note: This code is currently preview quality. Preview 9 ChangesAdded support for trends Added support for Silverlight 4 Elevated WP7 fixes Third Party Library VersionsHammock v1.1.7: http://hammock.codeplex.com Json.NET 4.0 Release 1: http://json.codeplex.comFacebook Graph Toolkit: Facebook Graph Toolkit 0.7: Version 0.7 updates (2 Feb 2011)new Facebook Graph objects: Link, Note, StatusMessage new publish features: status update, post with link attachment new Graph Api connections in User object: statuses, links, notes internal code path improvement on Api object bug fixed: extra "r" character appears for strings with "\r" symbols in Json Objects bug fixed: error when performing Postback to the same page Tutorial and documentation available at http://fbgraph.computerbeacon.netChemistry Add-in for Word: Chemistry Add-in for Word - Version 1.0: On February 1, 2011, we announced the availability of version 1 of the Chemistry Add-in for Word, as well as the assignment of the open source project to the Outercurve Foundation by Microsoft Research and the University of Cambridge. System RequirementsHardware RequirementsAny computer that can run Office 2007 or Office 2010. Software RequirementsYour computer must have the following software: Any version of Windows that can run Office 2007 or Office 2010, which includes Windows XP SP3 and...Minemapper: Minemapper v0.1.4: Updated mcmap, now supports new block types. Added a Worlds->'View Cache Folder' menu item.StyleCop for ReSharper: StyleCop for ReSharper 5.1.15005.000: Applied patch from rodpl for merging of stylecop setting files with settings in parent folder. Previous release: A considerable amount of work has gone into this release: Huge focus on performance around the violation scanning subsystem: - caching added to reduce IO operations around reading and merging of settings files - caching added to reduce creation of expensive objects Users should notice condsiderable perf boost and a decrease in memory usage. Bug Fixes: - StyleCop's new Objec...Minecraft Tools: Minecraft Topographical Survey 1.4: MTS requires version 4 of the .NET Framework - you must download it from Microsoft if you have not previously installed it. This version of MTS adds MCRegion support and fixes bugs that caused rendering to fail for some users. New in this version of MTS: Support for rendering worlds compressed with MCRegion Fixed rendering failure when encountering non-NBT files with the .dat extension Fixed rendering failure when encountering corrupt NBT files Minor GUI updates Note that the command...MVC Controls Toolkit: Mvc Controls Toolkit 0.8: Fixed the following bugs: *Variable name error in the jvascript file that prevented the use of the deleted item template of the Datagrid *Now after the changes applied to an item of the DataGrid are cancelled all input fields are reset to the very initial value they had. *Other minor bugs. Added: *This version is available both for MVC2, and MVC 3. The MVC 3 version has a release number of 0.85. This way one can install both version. *Client Validation support has been added to all control...Office Web.UI: Beta preview (Source): This is the first Beta. it includes full source code and all available controls. Some designers are not ready, and some features are not finalized allready (missing properties, draft styles) ThanksASP.net Ribbon: Version 2.2: This release brings some new controls (part of Office Web.UI). A few bugs are fixed and it includes the "auto resize" feature as you resize the window. (It can cause an infinite loop when the window is too reduced, it's why this release is not marked as "stable"). I will release more versions 2.3, 2.4... until V3 which will be the official launch of Office Web.UI. Both products will evolve at the same speed. Thanks.xUnit.net - Unit Testing for .NET: xUnit.net 1.7: xUnit.net release 1.7Build #1540 Important notes for Resharper users: Resharper support has been moved to the xUnit.net Contrib project. Important note for TestDriven.net users: If you are having issues running xUnit.net tests in TestDriven.net, especially on 64-bit Windows, we strongly recommend you upgrade to TD.NET version 3.0 or later. This release adds the following new features: Added support for ASP.NET MVC 3 Added Assert.Equal(double expected, double actual, int precision) Ad...New ProjectsADE: ADE cmsAlicia - Elastic LoadBalancer: Alicia is a HTTP & HTTPS LoadBalancer. It is meant to be put in front of a server cluster. It implements a simple round robin mechanism. The default ports used are 1) HTTP 10080 2) HTTPS 10443 3) Admin 10010CMake syntax highlighting for Visual Studio 2010: CMake (http://cmake.org) is a cross platform build tool that works just as well with Visual Studio as it does with Xcode or the gnu make environment. This project aims to add syntax highlighting for the CMake script language to Visual Studio 2010 and is written in C#. ConCatJS: ConCatJS is a simple application that is capable of recursively processing directories and concatenating the JavaScript files therein into a single file.FicusFactor Image Watermarking Plugin for Windows Live Photo Gallery: Simple plugin for Windows Live Photo Gallery that can be used for applying watermarks to images. Can configure text, font, and placement of watermarks.FlMML: FlMML is a actionscript 3.0 library. It is made for generating sounds with MML. GSMock: GSMock is a mocking utility for the Google Search Appliance. It enables search responses to be mocked for search requests. GUIMaLoRT: The GUI for the MaLoRT.HushDB: This is a simple relational database. Its main purpose is to help people improve the understanding of how RDBMS is implemented after taking the database cource in university.Medical Log: Crear un registro de consultas medicas que facilite la gestión de los pacientes y manejo de información por reportes. Medical Log facilita el uso de registros de pacientes a médicos para obtener mayor información y más rápida de sus pacientes. Desarrollado con WPF .NET 4.0 MetaMold: semantic data through dynamic objects: MetaMold is a library to simplify the manipulation of semantic data through the usage of dynamic objects and pluggable convention-based mappings.My First Facebook Application: This is devoted to my first Facebook application.Nintemulator: A single software solution that offers support for a wide array of nintendo consoles.Orchard Facebook Like Widget: This is the project for the Facebook Like Widget module for the Orchard Project.Peggle: Its 2d game developed in c++ using qt and box2d. it helps developers to understand how to use box2d and qt efficiently. Pet Shelter - ASP.NET MVC 3 Learning Experiment: A web site for pet shelter managers and simple users who try to find their own pets, or to adopt one. This project is basically an ASP.NET MVC 3 learning experiment so if you want to join please contact me. It is developed in .NET 4.0, specifically C#. Robot-One ITI Cesena: Programma e documentazione per il Robot-One, il robottone cingolato dell'ITI di Cesena. Running Portal: Portal of 100loopRunning SharePoint List Based 404 Handler: A SharePoint WSP that customises the 404 handler for a web application, allowing you to define how to handle missing page requests via a SharePoint list.SharpSerializer: SharpSerializer is an open source XML and binary serializer for .NET Framework, .NET Compact Framework and Silverlight. It was developed with C#. Actually SharpSerializer can serialize to Xml and to its own binary format.SocialTank: Fill up the tank with social stuff!SQL Space Map: SQL Space Map is a tool that lets you quickly and easily view the relative size of database objects on a map, so you can compare them visually. It helps identify large objects, objects with a high index/data ratio, and tables which may be growing more quickly than expected.Supernover framework: SAF( SuperNover Application Framework)ToolBlog: Space reserved for the ToolBlog, which is a study about a site/blog in ASP.NET MVC 3Useful C# Extensions and Code generator: Initially a private repository, I want to make my collection of extensions and a code generating framework public. XnaLoop: simple test of xna game loop

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• concurrency::accelerator_view

  - by Daniel Moth

  Overview We saw previously that accelerator represents a target for our C++ AMP computation or memory allocation and that there is a notion of a default accelerator. We ended that post by introducing how one can obtain accelerator_view objects from an accelerator object through the accelerator class's default_view property and the create_view method. The accelerator_view objects can be thought of as handles to an accelerator. You can also construct an accelerator_view given another accelerator_view (through the copy constructor or the assignment operator overload). Speaking of operator overloading, you can also compare (for equality and inequality) two accelerator_view objects between them to determine if they refer to the same underlying accelerator. We'll see later that when we use concurrency::array objects, the allocation of data takes place on an accelerator at array construction time, so there is a constructor overload that accepts an accelerator_view object. We'll also see later that a new concurrency::parallel_for_each function overload can take an accelerator_view object, so it knows on what target to execute the computation (represented by a lambda that the parallel_for_each also accepts). Beyond normal usage, accelerator_view is a quality of service concept that offers isolation to multiple "consumers" of an accelerator. If in your code you are accessing the accelerator from multiple threads (or, in general, from different parts of your app), then you'll want to create separate accelerator_view objects for each thread. flush, wait, and queuing_mode When you create an accelerator_view via the create_view method of the accelerator, you pass in an option of immediate or deferred, which are the two members of the queuing_mode enum. At any point you can access this value from the queuing_mode property of the accelerator_view. When the queuing_mode value is immediate (which is the default), any commands sent to the device such as kernel invocations and data transfers (e.g. parallel_for_each and copy, as we'll see in future posts), will get submitted as soon as the runtime sees fit (that is the definition of immediate). When the value of queuing_mode is deferred, the commands will be batched up. To send all buffered commands to the device for execution, there is a non-blocking flush method that you can call. If you wish to block until all the commands have been sent, there is a wait method you can call. Deferring is a more advanced scenario aimed at performance gains when you are submitting many device commands and you want to avoid the tiny overhead of flushing/submitting each command separately. Querying information Just like accelerator, accelerator_view exposes the is_debug and version properties. In fact, you can always access the accelerator object from the accelerator property on the accelerator_view class to access the accelerator interface we looked at previously. Interop with D3D (aka DX) In a later post I'll show an example of an app that uses C++ AMP to compute data that is used in pixel shaders. In those scenarios, you can benefit by integrating C++ AMP into your graphics pipeline and one of the building blocks for that is being able to use the same device context from both the compute kernel and the other shaders. You can do that by going from accelerator_view to device context (and vice versa), through part of our interop API in amp.h: *get_device, create_accelerator_view. More on those in a later post. Comments about this post by Daniel Moth welcome at the original blog.

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• Having fun with Reflection

  - by Nick Harrison

  I was once asked in a technical interview what I could tell them about Reflection.   My response, while a little tongue in cheek was that "I can tell you it is one of my favorite topics to talk about" I did get a laugh out of that and it was a great ice breaker.    Reflection may not be the answer for everything, but it often can be, or maybe even should be.     I have posted in the past about my favorite CopyTo method.   It can come in several forms and is often very useful.   I explain it further and expand on the basic idea here  The basic idea is to allow reflection to loop through the properties of two objects and synchronize the ones that are in common.   I love this approach for data binding and passing data across the layers in an application. Recently I have been working on a project leveraging Data Transfer Objects to pass data through WCF calls.   We won't go into how the architecture got this way, but in essence there is a partial duplicate inheritance hierarchy where there is a related Domain Object for each Data Transfer Object.     The matching objects do not share a common ancestor or common interface but they will have the same properties in common.    By passing the problems with this approach, let's talk about how Reflection and our friendly CopyTo could make the most of this bad situation without having to change too much. One of the problems is keeping the two sets of objects in synch.   For this particular project, the DO has all of the functionality and the DTO is used to simply transfer data back and forth.    Both sets of object have parallel hierarchies with the same properties being defined at the corresponding levels.   So we end with BaseDO,  BaseDTO, GenericDO, GenericDTO, ProcessAreaDO,  ProcessAreaDTO, SpecializedProcessAreaDO, SpecializedProcessAreaDTO, TableDo, TableDto. and so on. Without using Reflection and a CopyTo function, tremendous care and effort must be made to keep the corresponding objects in synch.    New properties can be added at any level in the inheritance and must be kept in synch at all subsequent layers.    For this project we have come up with a clever approach of calling a base GetDo or UpdateDto making sure that the same method at each level of inheritance is called.    Each level is responsible for updating the properties at that level. This is a lot of work and not keeping it in synch can create all manner of problems some of which are very difficult to track down.    The other problem is the type of code that this methods tend to wind up with. You end up with code like this: Transferable dto = new Transferable(); base.GetDto(dto); dto.OfficeCode = GetDtoNullSafe(officeCode); dto.AccessIndicator = GetDtoNullSafe(accessIndicator); dto.CaseStatus = GetDtoNullSafe(caseStatus); dto.CaseStatusReason = GetDtoNullSafe(caseStatusReason); dto.LevelOfService = GetDtoNullSafe(levelOfService); dto.ReferralComments = referralComments; dto.Designation = GetDtoNullSafe(designation); dto.IsGoodCauseClaimed = GetDtoNullSafe(isGoodCauseClaimed); dto.GoodCauseClaimDate = goodCauseClaimDate;       One obvious problem is that this is tedious code.   It is error prone code.    Adding helper functions like GetDtoNullSafe help out immensely, but there is still an easier way. We can bypass the tedious code, by pass the complex inheritance tricks, and reduce all of this to a single method in the base class. TransferObject dto = new TransferObject(); CopyTo (this, dto); return dto; In the case of this one project, such a change eliminated the need for 20% of the total code base and a whole class of unit test cases that made sure that all of the properties were in synch. The impact of such a change also needs to include the on going time savings and the improvements in quality that can arise from them.    Developers who are not worried about keeping the properties in synch across mirrored object hierarchies are freed to worry about more important things like implementing business requirements.

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• With 2 superposed cameras at different depths and switching their culling masks between layers to implement object-selective antialising:

  - by user36845

  We superposed two cameras, one of which uses AA as post-processing effect (AA filtering is cancelled). The camera with the AA effect has depth 0 and the camera with no effect has depth 1 as can be seen in the 5th and 6th Picture. The objects seen on the left are in layer 1 and the ones on the right are in layer 2. We then wrote a script that switches the culling masks of the cameras between the two layers at the push of buttons 1 and 2 respectively, and accomplishes object-selective antialiasing as seen in the first the three pictures. (The way two cameras separately switch culling masks between layers is illustrated in pictures 7,8 & 9.) HOWEVER, after making the environment 3D (see pictures 1-4), by parenting the 2 cameras under First-Person Controller, we started moving around in the environment and stumbled upon a big issue: When we look at the objects from such an angle as in the 4th Picture and we want to apply antialiasing to the first object (object on the left) which stands closer to our cameras now, the culling mask of 1st camera which is at depth 0, has to be switched to that object’s layer while the second object has to be in the culling mask of the 2nd camera at depth 1. And since the two image outputs of two superposed cameras are laid on top of one another; we obtain the erroneous/unrealistic result of the object farther in the back appearing closer to the camera than the front object (see 4th Picture). We already tried switching depths of cameras so that the 1st camera –with AA- now has depth 1 and the second has depth 0; BUT the camera with the AA effect Works in such a way that it applies the AA effect to its full view. So; the camera with the AA effect always has to remain at the lowest depth and the layer of the object to be antialiased has to be then assigned to the culling mask of the AA camera; otherwise all objects in the AA camera’s view (the two cubes in our case) become antialised, which we don’t want. So; how can we resolve this? The pictures are below and in the comments since each post can have 2 pics: Pic 1. No button is pushed: Both objects seem aliased. Pic 2. Button 1 is pushed: Left (1st) object is antialiased. 2nd object remains aliased. Pic 3. Button 2 is pushed: Right (2nd) object is antialiased. 1st object remains aliased. Pic 4. The problematic result in 3D, when using two superposed cameras with different depths Pic 5. Camera 1’s properties can be seen: using AA post-processing and its depth is 0 Pic 6. Camera 2’s properties can be seen: NOT using AA post-processing and its depth is 1 Pic 7. When no button is pushed, both objects are in the culling mask of Camera 2 and are aliased Pic 8. When pushed 1, camera 1 (bottom) shows the 1st object and camera 2 (top) shows the 2nd Pic 9. When pushed 2, camera 1 (bottom) shows the 2nd object and camera 2 (top) shows the 1st

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• ResourceSerializable: an alternate to ORM and ActiveRecord

  - by Levi Morrison

  A few opinionated reasons I don't like the traditional ORM and ActiveRecord patterns: They work only with a database. Sometimes I'm dealing with objects from an API and other objects from a database. All the implementations I have seen don't allow for that. Feel free to clue me in if I'm wrong on this. They are brittle. Changes in the database will likely break your implemenation. Some implementations can help reduce this, but a few of the ones I've seen don't. Their very design is influenced by the database. If I want to switch to using an API, I'll have to redesign the object to get it to work (likely). It seems to violate the single-responsibility pattern. They know what they are and how they act, but they also know how they are created, destroyed and saved? Seems a bit much. What about an approach that is somewhat more familiar in PHP: implementing an interface? In php 5.4, we'll have the JsonSerializable interface that defines the data to be json_encoded, so users will become accustomed to this type of thing. What if there was a ResourceSerializable interface? This is still an ORM by name, but certainly not by tradition. interface ResourceSerializable { /** * Returns the id that identifies the resource. */ function resourceId(); /** * Returns the 'type' of the resource. */ function resourceType(); /** * Returns the data to be serialized. */ function resourceSerialize(); } Things might be poorly named, I'll take suggestions. Notes: ResourceId will work for API's and databases. As long as your primary key in the database is the same as the resource ID in the API, there is no conflict. All of the API's I've worked with have a unique ID for the resource, so I don't see any issues there. ResourceType is the group or type associated with the resource. You can use this to map the resource to an API call or a database table. If the ResourceType was person, it could map to /api/1/person/{resourceId} and the table persons (or people, if it's smart enough). resourceSerialize() returns the data to be stored. Keys would identify API parameters and database table columns. This also seems easier to test than ActiveRecord / Orm implemenations. I haven't done much automated testing on traditional ActiveRecord/ORM implemenations, so this is merely a guess. But it seems that I being able to create objects independently of the library helps me. I don't have to use load() to get an existing resource, I can simply create one and set all the right properties. This is not so easy in the ActiveRecord / Orm implemenations I've dealt with. Downsides: You need another object to serialize it. This also means you have more code in general as you have to use more objects. You have to map resource types to API calls and database tables. This is even more work, but some ORMs and ActiveRecord implementations require you to map objects to table names anyway. Are there other downsides that you see? Does this seem feasible to you? How would you improve it? Note: I almost asked this on StackOverflow because it might be too vague for their standards, but I'm still not really familiar with programmers.stackexchange.com, so please help me improve my question if it doesn't shape up to standards here.

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• Why should I use Amazon Route 53 over my registrar's DNS servers?

  - by Abtin Forouzandeh

  I am building a site that I anticipate will have high usage. Currently, my registrar (GoDaddy) is handling DNS. However, Amazon's Route 53 looks interesting. They promise high speed and offer globally distributed DNS servers and a programmable interface. While GoDaddy doesn't offer a programmable interface, I assume their servers are geographically distributed as well. What are the main reasons I should opt to use Amazon Route 53 over free registrar-based DNS?

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• Doubts about several best practices for rest api + service layer

  - by TheBeefMightBeTough

  I'm going to be starting a project soon that exposes a restful api for business intelligence. It may not be limited to a restful api, so I plan to delegate requests to a service layer that then coordinates multiple domain objects (each of which have business logic local to the object). The api will likely have many calls as it is a long-term project. While thinking about the design, I recalled a few best practices. 1) Use command objects at the controller layer (I'm using Spring MVC). 2) Use DTOs at the service layer. 3) Validate in both the controller and service layer, though for different reasons. I have my doubts about these recommendations. 1) Using command objects adds a lot of extra single-purpose classes (potentially one per request). What exactly is the benefit? Annotation based validation can be done using this approach, sure. What if I have two requests that take the same parameters, but have different validation requirements? I would have to have two different classes with exactly the same members but different annotations? Bleh. 2) I have heard that using DTOs is preferable to parameters because it makes for more maintainable code down the road (say, e.g., requirements change and the service parameters need to be altered). I don't quite understand this. Shouldn't an api be more-or-less set in stone? I would understand that in the early phases of a project (or, especially, an entire company) the domain itself will not be well understood, and thus core domain objects may change along with the apis that manipulate these objects. At this point however the number of api methods should be small and their dependents few, so changes to the methods could easily be tolerated from a maintainability standpoint. In a large api with many methods and a substantial domain model, I would think having a DTO for potentially each domain object would become unwieldy. Am I misunderstanding something here? 3) I see validation in the controller and service layer as redundant in most cases. Why would I validate that parameters are not null and are in general well formed in the controller if the service is going to do exactly the same (and more). Couldn't I just do all the validation in the service and throw a runtime exception with a list of bad parameters then catch that in the controller to make the error messages more presentable? Better yet, couldn't I just make the error messages user-friendly in the service and let the exception trickle up to a global handler (ControllerAdvice in spring, for example)? Is there something wrong with either of these approaches? (I do see a use case for controller validation if the input does not map one-to-one with the service input, but since the controllers are for a rest api and not forms, the api parameters will probably map directly to service parameters.) I do also have a question about unchecked vs checked exceptions. Namely, I'm not really sure why I'd ever want to use a checked exception. Every time I have seen them used they just get wrapped into general exceptions (DomainException, SystemException, ApplicationException, w/e) to reduce the signature length of methods, or devs catch Exception rather than dealing with the App1Exception, App2Exception, Sys1Exception, Sys2Exception. I don't see how either of these practices is very useful. Why not just use unchecked exceptions always and catch the ones you actually do care about? You could just document what unchecked exceptions the method throws.

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• WF4 &ndash; Guess the number game!

  - by MarkPearl

  I posted yesterday how really good WF4 was looking. Today I thought I would show some real basics that I was able to figure out. This will be a simple example, I am going to make a flowchart workflow – which will prompt the user to guess the number until they guess the right number. Lets begin… Make a new project and make it a Workflow console Application. Then select the Workflow file and drag a FlowChart (2) to point 3. This will now show a green start circle in the designer form. We are going to work with primitives to start with. We are now going to drag a few objects onto the Workflow, We drag the WriteLine, Assign & Decision items onto the designer. Once they are dragged onto the designer we will want to link them up. The order that they are linked is critical since this will determine the order of the solution. In this case, we want the system to first ask “Guess a number”, then to wait for the user to input some code, and then to display “You got it” if they got it right, and “Try again” if they got it wrong. So we now link the arrows to the objects. This is done by moving the mouse pointer over the start objects and clicking on one of the toggles and then dragging it to the next object and releasing the button over one of the toggles. This will place an arrow from the source object to the target object. Okay… pretty simple stuff – now we just need these primitive objects to do stuff. Lets start with the WriteLine primitive. We place the text in inverted commas in the Text field. Because this field accepts any valid VB expression we could have put variables etc. in there if we wanted to. The next thing we want to do is allow the user to input a number. This brings up an interesting problem, if a user were to type in a number, there would need to be someway to declare a variable to hold that value for the life of the workflow. We can achieve this by declaring a variable. To declare a variable, move your cursor over the variables tab at the bottom of the workflow, and then type the name of the new variable in the “Create Variable” field and set it as shown in the image above. Now that we have a variable, we want to call the Console.Readline method and assign the inputted value from the Console to that variable. The code that cannot be seen is actually this – Convert.ToInt32(Console.ReadLine()) We now have a workflow that first prompts the user for a number, then allows the user to type in a number. We are almost done, we just need to make the system react to the value inputted. There are a few ways we could do this, I am going to use the Decision item. So select the Decision object on the designer and then view its properties (F4 for me), and in the condition field place a condition. For simplicity sake I have decided that if the user guesses 10, they will have guessed the number. This is now the completed workflow. Its really easy to understand and shows some really powerful principles for Business applications. You can run the application and see what it does. Imagine writing business solutions that do not worry about the exact flow of objects, but simply allows a business analyst or someone to configure the solution to work exactly as the business rules would dictate. And if the rules changed six months later all they would need to do is re-drag some of the flows. Now I do not know if WF4 will allow for this, but it feels like it is a step in the right direct.

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• Writing a method to 'transform' an immutable object: how should I approach this?

  - by Prog

  (While this question has to do with a concrete coding dilemma, it's mostly about what's the best way to design a function.) I'm writing a method that should take two Color objects, and gradually transform the first Color into the second one, creating an animation. The method will be in a utility class. My problem is that Color is an immutable object. That means that I can't do color.setRGB or color.setBlue inside a loop in the method. What I can do, is instantiate a new Color and return it from the method. But then I won't be able to gradually change the color. So I thought of three possible solutions: 1- The client code includes the method call inside a loop. For example: int duration = 1500; // duration of the animation in milliseconds int steps = 20; // how many 'cycles' the animation will take for(int i=0; i<steps; i++) color = transformColor(color, targetColor, duration, steps); And the method would look like this: Color transformColor(Color original, Color target, int duration, int steps){ int redDiff = target.getRed() - original.getRed(); int redAddition = redDiff / steps; int newRed = original.getRed() + redAddition; // same for green and blue .. Thread.sleep(duration / STEPS); // exception handling omitted return new Color(newRed, newGreen, newBlue); } The disadvantage of this approach is that the client code has to "do part of the method's job" and include a for loop. The method doesn't do it's work entirely on it's own, which I don't like. 2- Make a mutable Color subclass with methods such as setRed, and pass objects of this class into transformColor. Then it could look something like this: void transformColor(MutableColor original, Color target, int duration){ final int STEPS = 20; int redDiff = target.getRed() - original.getRed(); int redAddition = redDiff / steps; int newRed = original.getRed() + redAddition; // same for green and blue .. for(int i=0; i<STEPS; i++){ original.setRed(original.getRed() + redAddition); // same for green and blue .. Thread.sleep(duration / STEPS); // exception handling omitted } } Then the calling code would usually look something like this: // The method will usually transform colors of JComponents JComponent someComponent = ... ; // setting the Color in JComponent to be a MutableColor Color mutableColor = new MutableColor(someComponent.getForeground()); someComponent.setForeground(mutableColor); // later, transforming the Color in the JComponent transformColor((MutableColor)someComponent.getForeground(), new Color(200,100,150), 2000); The disadvantage is - the need to create a new class MutableColor, and also the need to do casting. 3- Pass into the method the actual mutable object that holds the color. Then the method could do object.setColor or similar every iteration of the loop. Two disadvantages: A- Not so elegant. Passing in the object that holds the color just to transform the color feels unnatural. B- While most of the time this method will be used to transform colors inside JComponent objects, other kinds of objects may have colors too. So the method would need to be overloaded to receive other types, or receive Objects and have instanceof checks inside.. Not optimal. Right now I think I like solution #2 the most, than solution #1 and solution #3 the least. However I'd like to hear your opinions and suggestions regarding this.

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