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What is the chain of responsibility design pattern?
Chain-of-responsibility pattern. In object-oriented design, the chain-of-responsibility pattern is a design pattern consisting of a source of command objects and a series of processing objects.
What happens at the end of a chain of responsibility?
A mechanism also exists for adding new processing objects to the end of this chain. In a variation of the standard chain-of-responsibility model, some handlers may act as dispatchers, capable of sending commands out in a variety of directions, forming a tree of responsibility.
How is a chain of receiver objects defined?
Define a chain of receiver objects having the responsibility, depending on run-time conditions, to either handle a request or forward it to the next receiver on the chain (if any). This enables us to send a request to a chain of receivers without having to know which one handles the request.
Why do we use arrays instead of other data structures?
While an array offers less functionality, it takes up less RAM, and the compiler can optimize code more efficiently for look-ups into arrays. I am sure I am leaving out a number of the benefits for these cases, but I hope you get the point.
Are there any design patterns for handling errors?
I have, however, never seen any design pattern covering the issue of where and how best to handle errors and how best to propagate an error appearing in a low-level function up the levels of abstraction. Best approach is never to swallow any exceptions within your application code.
How are handlers handled in a chain of responsibility?
Each of the handlers in the chain takes its turn at trying to handle the request it receives from the client. If ConcreteHandler1 can handle it, then the request is handled, if not it is sent to the handler ConcreteHandler2, the next one in the chain.
What are the two design patterns in messaing?
There are two patterns within messaing: one-to-one and one-to-many. We talked about some of the complexity synchronous style brings, but some of it is eliminated by default in the messaging style.