docs: Improve Chain of Responsibility docs

chain-of-responsibility/README.md

@@ -3,9 +3,16 @@ title: Chain of responsibility
 category: Behavioral
 language: en
 tag:
- - Gang of Four
+  - Gang of Four
+  - Decoupling
 ---
 
+## Also known as
+
+* Chain of Command
+* Chain of Objects
+* Responsibility Chain
+
 ## Intent
 
 Avoid coupling the sender of a request to its receiver by giving more than one object a chance to 
@@ -36,6 +43,9 @@ Wikipedia says
 Translating our example with the orcs from above. First, we have the `Request` class:
 
 ```java
+import lombok.Getter;
+
+@Getter
 public class Request {
 
   private final RequestType requestType;
@@ -46,17 +56,15 @@ public class Request {
     this.requestType = Objects.requireNonNull(requestType);
     this.requestDescription = Objects.requireNonNull(requestDescription);
   }
-
-  public String getRequestDescription() { return requestDescription; }
-
-  public RequestType getRequestType() { return requestType; }
-
-  public void markHandled() { this.handled = true; }
-
-  public boolean isHandled() { return this.handled; }
-
+  
+  public void markHandled() {
+    this.handled = true;
+  }
+  
   @Override
-  public String toString() { return getRequestDescription(); }
+  public String toString() {
+    return getRequestDescription();
+  }
 }
 
 public enum RequestType {
@@ -163,11 +171,37 @@ Use Chain of Responsibility when
 
 ## Known uses
 
+* Event bubbling in GUI frameworks where an event might be handled at multiple levels of a UI component hierarchy
+* Middleware frameworks where a request passes through a chain of processing objects
+* Logging frameworks where messages can be passed through a series of loggers, each possibly handling them differently
 * [java.util.logging.Logger#log()](http://docs.oracle.com/javase/8/docs/api/java/util/logging/Logger.html#log%28java.util.logging.Level,%20java.lang.String%29)
 * [Apache Commons Chain](https://commons.apache.org/proper/commons-chain/index.html)
 * [javax.servlet.Filter#doFilter()](http://docs.oracle.com/javaee/7/api/javax/servlet/Filter.html#doFilter-javax.servlet.ServletRequest-javax.servlet.ServletResponse-javax.servlet.FilterChain-)
 
+## Consequences
+
+Benefits:
+
+* Reduced coupling. The sender of a request does not need to know the concrete handler that will process the request.
+* Increased flexibility in assigning responsibilities to objects. You can add or change responsibilities for handling a request by changing the members and order of the chain.
+* Allows you to set a default handler if no concrete handler can handle the request.
+
+Trade-Offs:
+
+* It can be challenging to debug and understand the flow, especially if the chain is long and complex.
+* The request might end up unhandled if the chain doesn't include a catch-all handler.
+* Performance concerns might arise due to potentially going through several handlers before finding the right one, or not finding it at all.
+
+## Related Patterns
+
+[Command](https://java-design-patterns.com/patterns/command/): can be used to encapsulate a request as an object, which might be passed along the chain.
+[Composite](https://java-design-patterns.com/patterns/composite/): the Chain of Responsibility is often applied in conjunction with the Composite pattern.
+[Decorator](https://java-design-patterns.com/patterns/decorator/): decorators can be chained in a similar manner as responsibilities in the Chain of Responsibility pattern.
+
 ## Credits
 
 * [Design Patterns: Elements of Reusable Object-Oriented Software](https://www.amazon.com/gp/product/0201633612/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=0201633612&linkCode=as2&tag=javadesignpat-20&linkId=675d49790ce11db99d90bde47f1aeb59)
 * [Head First Design Patterns: A Brain-Friendly Guide](https://www.amazon.com/gp/product/0596007124/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=0596007124&linkCode=as2&tag=javadesignpat-20&linkId=6b8b6eea86021af6c8e3cd3fc382cb5b)
+* [Pattern-Oriented Software Architecture, Volume 1: A System of Patterns](https://amzn.to/3PAJUg5)
+* [Refactoring to Patterns](https://amzn.to/3VOO4F5)
+* [Pattern languages of program design 3](https://amzn.to/4a4NxTH)

chain-of-responsibility/src/main/java/com/iluwatar/chain/Request.java

@@ -25,10 +25,12 @@
 package com.iluwatar.chain;
 
 import java.util.Objects;
+import lombok.Getter;
 
 /**
  * Request.
  */
+@Getter
 public class Request {
 
   /**
@@ -59,25 +61,6 @@ public class Request {
     this.requestDescription = Objects.requireNonNull(requestDescription);
   }
 
-  /**
-   * Get a description of the request.
-   *
-   * @return A human readable description of the request
-   */
-  public String getRequestDescription() {
-    return requestDescription;
-  }
-
-  /**
-   * Get the type of this request, used by each person in the chain of command to see if they should
-   * or can handle this particular request.
-   *
-   * @return The request type
-   */
-  public RequestType getRequestType() {
-    return requestType;
-  }
-
   /**
    * Mark the request as handled.
    */
@@ -85,15 +68,6 @@ public class Request {
     this.handled = true;
   }
 
-  /**
-   * Indicates if this request is handled or not.
-   *
-   * @return <tt>true</tt> when the request is handled, <tt>false</tt> if not
-   */
-  public boolean isHandled() {
-    return this.handled;
-  }
-
   @Override
   public String toString() {
     return getRequestDescription();