Update README.md

Author: iluwatar

separated-interface/README.md

@@ -10,23 +10,35 @@ tags:
 
 
 ## Intent
-Separate the interface definition and implementation in different packages. This allows the client to be completely unaware of the implementation.
+
+Separate the interface definition and implementation in different packages. This allows the client 
+to be completely unaware of the implementation.
 
 ## Explanation
 
 Real world example
 
-> An Invoice generator may be created with ability to use different Tax calculators that may be added in the invoice depending upon type of purchase, region etc.         
+> An Invoice generator may be created with ability to use different Tax calculators that may be 
+> added in the invoice depending upon type of purchase, region etc.         
 
 In plain words
 
-> Separated interface pattern encourages to keep the implementations of an interface decoupled from the client and its definition, so the client is not dependent on the implementation.
+> Separated interface pattern encourages to keep the implementations of an interface decoupled from 
+> the client and its definition, so the client is not dependent on the implementation.
 
-A client code may abstract some specific functionality to an interface, and define the definition of the interface as an SPI ([Service Programming Interface](https://en.wikipedia.org/wiki/Service_provider_interface) is an API intended and open to be implemented or extended by a third party). Another package may implement this interface definition with a concrete logic, which will be injected into the client code at runtime (with a third class, injecting the implementation in the client) or at compile time (using Plugin pattern with some configurable file).
+A client code may abstract some specific functionality to an interface, and define the definition of 
+the interface as an SPI ([Service Programming Interface](https://en.wikipedia.org/wiki/Service_provider_interface) 
+is an API intended and open to be implemented or extended by a third party). Another package may 
+implement this interface definition with a concrete logic, which will be injected into the client 
+code at runtime (with a third class, injecting the implementation in the client) or at compile time 
+(using Plugin pattern with some configurable file).
 
 **Programmatic Example**
 
-**Client** An Invoice generator class accepts the cost of the product and calculates the total amount payable inclusive of tax
+**Client** 
+
+`InvoiceGenerator` class accepts the cost of the product and calculates the total 
+amount payable inclusive of tax.
 
 ```java
 public class InvoiceGenerator {
@@ -46,21 +58,23 @@ public class InvoiceGenerator {
 
 }
 ```
-The tax calculation logic is delegated to the ```TaxCalculator``` interface
 
-```java
+The tax calculation logic is delegated to the `TaxCalculator` interface.
 
+```java
 public interface TaxCalculator {
 
   double calculate(double amount);
 
 }
-
 ```
 
 **Implementation package**
-In another package (which the client is completely unaware of) there exist multiple implementations of the ```TaxCalculator``` interface
-```ForeignTaxCalculator``` which levies 60% tax for international products.
+
+In another package (which the client is completely unaware of) there exist multiple implementations 
+of the `TaxCalculator` interface. `ForeignTaxCalculator` is one of them which levies 60% tax 
+for international products.
+
 ```java
 public class ForeignTaxCalculator implements TaxCalculator {
 
@@ -74,7 +88,8 @@ public class ForeignTaxCalculator implements TaxCalculator {
 }
 ```
 
-```DomesticTaxCalculator``` which levies 20% tax for international products.
+Another is `DomesticTaxCalculator` which levies 20% tax for international products.
+
 ```java
 public class DomesticTaxCalculator implements TaxCalculator {
 
@@ -88,7 +103,8 @@ public class DomesticTaxCalculator implements TaxCalculator {
 }
 ```
 
-These both implementations are instantiated and injected in the client class by the ```App.java``` class
+These both implementations are instantiated and injected in the client class by the ```App.java``` 
+class.
 
 ```java
     var internationalProductInvoice = new InvoiceGenerator(PRODUCT_COST, new ForeignTaxCalculator());
@@ -101,9 +117,11 @@ These both implementations are instantiated and injected in the client class by
 ```
 
 ## Class diagram
+
 ![alt text](./etc/class_diagram.png "Separated Interface")
 
 ## Applicability
+
 Use the Separated interface pattern when
 
 * You are developing a framework package, and your framework needs to call some application code through interfaces.
@@ -117,3 +135,4 @@ Use the Separated interface pattern when
 ## Credits
 
 * [Martin Fowler](https://www.martinfowler.com/eaaCatalog/separatedInterface.html)
+* [Patterns of Enterprise Application Architecture](https://www.amazon.com/gp/product/0321127420/ref=as_li_qf_asin_il_tl?ie=UTF8&tag=javadesignpat-20&creative=9325&linkCode=as2&creativeASIN=0321127420&linkId=e08dfb7f2cf6153542ef1b5a00b10abc)