birt barcode maximo Atomicity in Objective-C

Access gs1 datamatrix barcode in Objective-C Atomicity

The UML diagram of the Memento pattern is extremely simple in that Concrete Implementation implements the interface IOriginator. The interface IOriginator has two methods, CreateMemento and SetState, that create the state of the object and assign the state of the object to the type Memento. In code terms, the Memento pattern is implemented by the following source code: class Memento { private string _buffer; public Memento( string buffer) { _buffer = buffer; } public string Buffer { get { return _buffer; } set { _buffer = value; } } } interface IOriginator { Memento CreateMemento(); void SetState( Memento state); } class Simple : IOriginator { private string _buffer; public Simple( string buffer) { _buffer = buffer; } public Memento CreateMemento() { return new Memento( _buffer); } public void SetState( Memento state) { _buffer = state.Buffer; } } The class Simple implements the method IOriginator, which has two methods, CreateMemento and SetState. The method CreateMemento instantiates the type Memento and assigns to Memento the state of a Simple instance. The method SetState assigns to Simple a state, which is stored in the Memento type. In the preceding example, Simple and Memento are nearly identical. The main difference is that Memento will always be a data object with read and write properties, and it represents the internal state of Simple, whereas Simple is an application logic object that is immutable, and may or may not expose its internal state. Realize that Simple is a pure objectoriented object that doesn t expose its internal state. On the other hand, Memento isn t a pure object-oriented object, and its internal state is its external state. The state in Memento is a copy of the state in Simple. This is very important to remember when an object hierarchy needs to be

inner field. All the remaining row fields are outer fields. In Figure 2-1, District and City are the outer row fields, and Category is the inner row field.

Logically defining data access as a separate layer enforces a separation between the business logic and any interaction with a database (or any other data source). This separation provides the flexibility to choose later whether to run the data access code on the same machine as the business logic, or on a separate machine. It also makes it much easier to change data sources without affecting the application. This is important because it enables switching from one database vendor to another at some point.

The Common Runtime Language (CLR) is the core .NET engine. The .NET libraries allow you to create applications that run on the CLR. The applications you create are thus merely an instance of the CLR.

Open Program.cs and add the following using statement: using System.Data.Services.Client;

Ideally, your test subject will be somewhat familiar with the scope of your application. In my case, my wife made the perfect test subject for Trip Cubby. Her job required quite a bit of driving, and she had been tracking her reimbursable mileage with a convoluted combination of sticky notes and scribbles in her calendar. Plus, she had been using an iPhone for a few months but was definitely not a power user. Next, you need to set up a scenario and ask the test subjects to actually use your application. The first time I had my wife test Trip Cubby, I handed her the iPhone and said, You just drove 33 miles to give a presentation at 123 Main Street. Try entering that information into Trip Cubby. Once your test users are in action, it s time for you to observe and resist the urge to intervene. It s best to have the test subjects vocalize their thoughts as they perform the actions. By watching people interact with your application and listening to their thoughts as they walk through various scenarios, you should start seeing potential improvements in the UI. If no one figures out that your cute little disk icon means save, maybe you should just use the word Save onscreen. If the testers keep tapping the wrong button on a cramped toolbar, maybe you should leave a couple buttons off and make the remaining buttons bigger. If users are completely stumped, and you have to intervene with several minutes of explanation, you should consider a complete overhaul of the UI! Usability testing is sometimes tough for developers who are attached to a particular UI implementation, but being flexible and willing to adjust the application to real world users is incredibly important. My wife Elizabeth s first use of Trip Cubby is provided in the following section to give you an idea of the sorts of things you might hear from users during this process.