docs: improve flyweight

flux/README.md

@@ -116,3 +116,5 @@ Trade-offs:
 ## Credits
 
 * [Flux - Application architecture for building user interfaces](http://facebook.github.io/flux/)
+* [Learning React: Modern Patterns for Developing React Apps](https://amzn.to/3Qdn9Pg)
+* [Pro React](https://amzn.to/3xNRttK)

flyweight/README.md

@@ -3,33 +3,30 @@ title: Flyweight
 category: Structural
 language: en
 tag:
- - Gang of Four
- - Performance
+    - Gang of Four
+    - Memory management
+    - Object composition
+    - Optimization
+    - Performance
 ---
 
 ## Intent
 
-Use sharing to support large numbers of fine-grained objects efficiently.
+The Flyweight pattern's primary intent is to reduce the number of objects created, decrease memory footprint and increase performance by sharing as much data as possible with similar objects.
 
 ## Explanation
 
 Real-world example
 
-> Alchemist's shop has shelves full of magic potions. Many of the potions are the same so there is 
-> no need to create a new object for each of them. Instead, one object instance can represent 
-> multiple shelf items so the memory footprint remains small.
+> Alchemist's shop has shelves full of magic potions. Many of the potions are the same so there is no need to create a new object for each of them. Instead, one object instance can represent  multiple shelf items so the memory footprint remains small.
 
 In plain words
 
-> It is used to minimize memory usage or computational expenses by sharing as much as possible with 
-> similar objects.
+> It is used to minimize memory usage or computational expenses by sharing as much as possible with similar objects.
 
 Wikipedia says
 
-> In computer programming, flyweight is a software design pattern. A flyweight is an object that 
-> minimizes memory use by sharing as much data as possible with other similar objects; it is a way 
-> to use objects in large numbers when a simple repeated representation would use an unacceptable 
-> amount of memory.
+> In computer programming, flyweight is a software design pattern. A flyweight is an object that minimizes memory use by sharing as much data as possible with other similar objects; it is a way to use objects in large numbers when a simple repeated representation would use an unacceptable amount of memory.
 
 **Programmatic example**
 
@@ -101,8 +98,7 @@ public class PotionFactory {
 }
 ```
 
-`AlchemistShop` contains two shelves of magic potions. The potions are created using the
-aforementioned `PotionFactory`.
+`AlchemistShop` contains two shelves of magic potions. The potions are created using the aforementioned `PotionFactory`.
 
 ```java
 @Slf4j
@@ -184,22 +180,38 @@ You feel blessed. (Potion=991505714)
 
 ## Applicability
 
-The Flyweight pattern's effectiveness depends heavily on how and where it's used. Apply the 
-Flyweight pattern when all of the following are true:
+The Flyweight pattern's effectiveness depends heavily on how and where it's used. Apply the Flyweight pattern when all the following are true:
 
 * An application uses a large number of objects.
 * Storage costs are high because of the sheer quantity of objects.
 * Most of the object state can be made extrinsic.
-* Many groups of objects may be replaced by relatively few shared objects once the extrinsic state 
-  is removed.
-* The application doesn't depend on object identity. Since flyweight objects may be shared, identity 
-tests will return true for conceptually distinct objects.
+* Many groups of objects may be replaced by relatively few shared objects once the extrinsic state is removed.
+* The application doesn't depend on object identity. Since flyweight objects may be shared, identity tests will return true for conceptually distinct objects.
 
 ## Known uses
 
 * [java.lang.Integer#valueOf(int)](http://docs.oracle.com/javase/8/docs/api/java/lang/Integer.html#valueOf%28int%29) and similarly for Byte, Character and other wrapped types.
+* Java’s String class, which uses the Flyweight pattern internally to manage string literals.
+* GUI applications, where objects like fonts or graphical components are shared rather than duplicated.
+
+## Consequences
+
+Benefits:
+
+* Reduces the number of instances of an object, conserving memory.
+* Centralizes state management, reducing the risk of inconsistent state.
+
+Trade-offs:
+
+* Increases complexity by adding the management layer for shared objects.
+* Potential overhead in accessing shared objects if not well implemented.
+
+## Related Patterns
+
+[Composite](https://java-design-patterns.com/patterns/composite/): Often combined with Flyweight when the composites are shareable. Both are used to manage hierarchies and structures of objects.
+[State](https://java-design-patterns.com/patterns/state/): Can be used to manage state in a shared Flyweight object, distinguishing internal state (invariant) from external state (context-specific).
 
 ## 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)
+* [Design Patterns: Elements of Reusable Object-Oriented Software](https://amzn.to/3w0pvKI)
+* [Head First Design Patterns: Building Extensible and Maintainable Object-Oriented Software](https://amzn.to/49NGldq)