What is the benefit of implementing the design pattern?
Design patterns help you write code faster by providing a clearer picture of how you are implementing the design. Design patterns encourage code reuse and accommodate change by supplying well-tested mechanisms for delegation and composition, and other non-inheritance based reuse techniques.
What problem does the command pattern solve?
Using the command design pattern can solve these problems: Coupling the invoker of a request to a particular request should be avoided. That is, hard-wired requests should be avoided. It should be possible to configure an object (that invokes a request) with a request.
What are design patterns and its need?
A design pattern provides a general reusable solution for the common problems that occur in software design. Design patterns are meant for common problem-solving. Whenever there is a need, you have to implement a suitable pattern to avoid such problems in the future.
What is a command pattern in design patterns?
Design Patterns – Command Pattern. Command pattern is a data driven design pattern and falls under behavioral pattern category. A request is wrapped under an object as command and passed to invoker object.
Where does the next page command pattern fall?
Next Page Command pattern is a data driven design pattern and falls under behavioral pattern category. A request is wrapped under an object as command and passed to invoker object. Invoker object looks for the appropriate object which can handle this command and passes the command to the corresponding object which executes the command.
Why do we use simple if-else in a command pattern?
By using simple if-else we are coding to implementation rather than interface. Also there is tight coupling. So what we want to achieve is a design that provides loose coupling and remote control should not have much information about a particular device. The command pattern helps us do that.
How is the command pattern used in redo?
Using the command pattern, we can wrap a command as an object. We use the command history to support arbitrary-level undo and redo. The following simple description of command history is from the book, Design Patterns. Conceptually, the command history looks like the following graph, each circle represents a command object.