Behavioral Patterns target issues related to communication and interaction between objects. They focus on defining protocols for collaboration among objects that are often too complex to design statically, enabling dynamic delegation of responsibilities at runtime.
OK, Let’s go through the description of the 1st behavioral pattern — Chain of Responsibility.
Context:
In some scenarios, multiple objects may be able to handle a request:
request may be processed by all objects one by one
request may be processed by all objects in some order which matters
request may be processed by several objects rather than all
the objects maybe changed at runtime, and cannot be known in advance
Here, multiple objects actually means some ‘logic’, like an article, the system will do some checking before accept this article:
checking if the user valid
checking if the user authorized
checking if the article data is empty
checking if the article data contains dirty words
checking if the article data is copied from others (checking similarity)
