ChainOfResponsibility definition and applicability

Author: hbrawnak

README.md

@@ -44,7 +44,18 @@ Define the skeleton of an algorithm in an operation, deferring some steps to sub
 
   * A class defines many behaviors, and these appear as multiple conditional statements in its operations. Instead of many conditionals, move related conditional branches into their own Strategy class.
 
+ 
+  #### 5.Chain of Responsibility
+  Avoid coupling the sender of a request to its receiver by giving more than one object a chance to handle the request. Chain the receiving objects and pass request along the chain until an object handles it. [example](https://github.com/hbrawnak/php-design-pattern/blob/master/ChainOfResponsibility/index.php#L3)
+ 
+##### Applicability:
+Use the Chain of Responsibility pattern when
+ 
+  * More than one object may handle a request, and the handler isn't known a priori. The handler should be ascertained automatically.
+  
+  * You want to issue a request to one of several objects without specifying the receiver explicitly.
 
+  * The set of objects that can handle a request should be specified dynamically. 
 
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  Sources: