Few additions in README

Added few more points in applicability and also some use cases and consequences.

abstract-factory/README.md

@@ -27,6 +27,22 @@ Use the Abstract Factory pattern when
 * a system should be configured with one of multiple families of products
 * a family of related product objects is designed to be used together, and you need to enforce this constraint
 * you want to provide a class library of products, and you want to reveal just their interfaces, not their implementations
+* the lifetime of the dependency is conceptually shorter than the lifetime of the consumer.
+*	you need a run-time value to construct a particular dependency
+*	you want to decide which product to call from a family at runtime.
+*	you need to supply one or more parameters only known at run-time before you can resolve a dependency.
+
+## Use Cases:	
+
+*	Selecting to call the appropriate implementation of FileSystemAcmeService or DatabaseAcmeService or NetworkAcmeService at runtime.
+*	Unit test case writing becomes much easier
+
+## Consequences:
+
+*	Dependency injection in java hides the service class dependencies that can lead to runtime errors that would have been caught at compile time.
+
+
+
 
 ## Real world examples