updated readme files for al patterns with pattern expanation

Author: vicmar57

AdapterPattern/README.md

@@ -1,5 +1,12 @@
 # Adapter Pattern
 
+The adapter pattern converts the interface of a class into an other interface that clients expect.
+Useful when slowly deprecating class/methods
+
+The pattern we want to maintain:
+Itarget target = new Adapter(new Adaptee());
+target. request();
+
 ## UML diagram:
 
 ![Alt text](AdapterPatternUML.jpg?raw=true "Pattern's UML diagram")

BridgePattern/README.md

@@ -1,5 +1,11 @@
 # Bridge Pattern
 
+The intent of the bridge pattern is to decouple an abstraction from 
+its implementation so that the two can vary independantly.
+
+Builds 2 polimorphic hirarcies.
+Prevents creation of all implementor-abstraction claas options.
+
 ## UML diagram:
 
 ![Alt text](BridgeUML.jpg?raw=true "Pattern's UML diagram")

CommandPattern/README.md

@@ -1,5 +1,9 @@
 # Command Pattern
 
+Encapsulates a request as an object thereby letting you parameterize other 
+objects with different requests, queue/log requests, and support undo-able operations.
+Useful when putting commands in a queue for instance/ building macros/ making a programmable remote control..
+
 ## UML diagram:
 
 ![Alt text](CommandUML.jpg?raw=true "Pattern's UML diagram")

CompositePattern/README.md

@@ -1,5 +1,8 @@
 # Composite Pattern
 
+The composite pattern composes objects into tree structures to represent part-whole hirarcies.
+Lets clients treat individual objects and composition objects, uniformaly.
+
 ## UML diagram:
 
 ![Alt text](CompositeUML.jpg?raw=true "Pattern's UML diagram")

Decorator_Pattern/README.md

@@ -1,5 +1,8 @@
 # Decorator Pattern
 
+Attaches additional responsibility to an object, dynamically. 
+Example - coffee+toppings (addons) price calculation.
+
 ## UML diagram:
 
 ![Alt text](DecoratorUML.jpg?raw=true "Pattern's UML diagram")

FacadePattern/README.md

@@ -1,5 +1,7 @@
 # Facade Pattern
 
+The facade pattern provides a unified interface to a set of interfaces in a sub-system.
+Facade defines a higher-level interface that makes the sub-system easier to use.
 ## UML diagram:
 
 ![Alt text](FacadeUML.jpg?raw=true "Pattern's UML diagram")

Factory_Pattern/README.md

@@ -1,5 +1,7 @@
 # Factory Pattern
 
+Defines an interface to creating objects but lets the subclasses decide which object to create.
+
 ## UML diagram:
 
 ![Alt text](FactoryUML.png?raw=true "Pattern's UML diagram")

IteratorPattern/README.md

@@ -1,5 +1,7 @@
 # Iterator Pattern
 
+Allows to iterate over a data structure sequencially, without knowing how the data structure is implemented.
+
 ## UML diagram:
 
 ![Alt text](IteratorUML.png?raw=true "Pattern's UML diagram")

NullObjectPattern/README.md

@@ -1,5 +1,10 @@
 # Null Object Pattern
 
+Replacing conditionals (if obj == null {...} else {...}) with polymorpism.
+Replaces a null with a null-object to avoid if statements.
+Also can represent a null-behaviour (for instance when collecting a power-up in a game,
+ that doesn't allow the player to move for x number of seconds).
+
 ## UML diagram:
 
 ![Alt text](NullObjectUML.png?raw=true "Pattern's UML diagram")

Observer_Pattern/README.md

@@ -1,5 +1,8 @@
 # Observer Pattern
 
+Tranfers control from a poll-push architecture, to a push-pull architecture, making the code event-driven.
+RxJava, the reactive java programming library (event driven programming), makes use of the Observer Pattern.
+
 ## UML diagram:
 
 ![Alt text](ObserverUML.png?raw=true "Pattern's UML diagram")