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iluwatariluwatar
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Added comments about object sharing in Flyweight example + some minor
fixes.
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2 files changed

+80
-77
lines changed

2 files changed

+80
-77
lines changed

‎flyweight/src/main/java/com/iluwatar/flyweight/AlchemistShop.java‎

Lines changed: 57 additions & 57 deletions
Original file line numberDiff line numberDiff line change
@@ -1,57 +1,57 @@
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package com.iluwatar.flyweight;
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import java.util.ArrayList;
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import java.util.List;
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/**
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*
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* AlchemistShop holds potions on its shelves.
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* It uses PotionFactory to provide the potions.
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*
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*/
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public class AlchemistShop {
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List<Potion> topShelf;
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List<Potion> bottomShelf;
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public AlchemistShop() {
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topShelf = new ArrayList<>();
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bottomShelf = new ArrayList<>();
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fillShelves();
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}
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private void fillShelves() {
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PotionFactory factory = new PotionFactory();
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topShelf.add(factory.createPotion(PotionType.INVISIBILITY));
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topShelf.add(factory.createPotion(PotionType.INVISIBILITY));
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topShelf.add(factory.createPotion(PotionType.STRENGTH));
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topShelf.add(factory.createPotion(PotionType.HEALING));
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topShelf.add(factory.createPotion(PotionType.INVISIBILITY));
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topShelf.add(factory.createPotion(PotionType.STRENGTH));
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topShelf.add(factory.createPotion(PotionType.HEALING));
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topShelf.add(factory.createPotion(PotionType.HEALING));
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bottomShelf.add(factory.createPotion(PotionType.POISON));
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bottomShelf.add(factory.createPotion(PotionType.POISON));
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bottomShelf.add(factory.createPotion(PotionType.POISON));
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bottomShelf.add(factory.createPotion(PotionType.HOLY_WATER));
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bottomShelf.add(factory.createPotion(PotionType.HOLY_WATER));
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}
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public void enumerate() {
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System.out.println("Enumerating top shelf potions\n");
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for (Potion p : topShelf) {
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p.drink();
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}
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System.out.println("\nEnumerating bottom shelf potions\n");
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for (Potion p : bottomShelf) {
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p.drink();
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}
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}
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}
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package com.iluwatar.flyweight;
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import java.util.ArrayList;
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import java.util.List;
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/**
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*
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* AlchemistShop holds potions on its shelves.
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* It uses PotionFactory to provide the potions.
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*
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*/
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public class AlchemistShop {
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private List<Potion> topShelf;
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private List<Potion> bottomShelf;
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public AlchemistShop() {
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topShelf = new ArrayList<>();
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bottomShelf = new ArrayList<>();
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fillShelves();
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}
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private void fillShelves() {
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PotionFactory factory = new PotionFactory();
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topShelf.add(factory.createPotion(PotionType.INVISIBILITY));
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topShelf.add(factory.createPotion(PotionType.INVISIBILITY));
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topShelf.add(factory.createPotion(PotionType.STRENGTH));
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topShelf.add(factory.createPotion(PotionType.HEALING));
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topShelf.add(factory.createPotion(PotionType.INVISIBILITY));
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topShelf.add(factory.createPotion(PotionType.STRENGTH));
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topShelf.add(factory.createPotion(PotionType.HEALING));
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topShelf.add(factory.createPotion(PotionType.HEALING));
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bottomShelf.add(factory.createPotion(PotionType.POISON));
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bottomShelf.add(factory.createPotion(PotionType.POISON));
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bottomShelf.add(factory.createPotion(PotionType.POISON));
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bottomShelf.add(factory.createPotion(PotionType.HOLY_WATER));
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bottomShelf.add(factory.createPotion(PotionType.HOLY_WATER));
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}
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public void enumerate() {
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System.out.println("Enumerating top shelf potions\n");
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for (Potion p : topShelf) {
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p.drink();
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}
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System.out.println("\nEnumerating bottom shelf potions\n");
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for (Potion p : bottomShelf) {
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p.drink();
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}
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}
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}

‎flyweight/src/main/java/com/iluwatar/flyweight/App.java‎

Lines changed: 23 additions & 20 deletions
Original file line numberDiff line numberDiff line change
@@ -1,20 +1,23 @@
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package com.iluwatar.flyweight;
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/**
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*
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* Flyweight pattern is useful when the program needs a huge amount of objects.
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* It provides means to decrease resource usage by sharing object instances.
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*
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* In this example AlchemistShop has great amount of potions on its shelves.
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* To fill the shelves AlchemistShop uses PotionFactory (which represents
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* the Flyweight in this example). Internally PotionFactory holds a map
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* of the potions and lazily creates new ones when requested.
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*
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*/
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public class App {
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public static void main(String[] args) {
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AlchemistShop alchemistShop = new AlchemistShop();
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alchemistShop.enumerate();
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}
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}
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package com.iluwatar.flyweight;
2+
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/**
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*
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* Flyweight pattern is useful when the program needs a huge amount of objects.
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* It provides means to decrease resource usage by sharing object instances.
7+
*
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* In this example AlchemistShop has great amount of potions on its shelves.
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* To fill the shelves AlchemistShop uses PotionFactory (which represents
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* the Flyweight in this example). Internally PotionFactory holds a map
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* of the potions and lazily creates new ones when requested.
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*
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* To enable safe sharing, between clients and threads, Flyweight objects must
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* be immutable. Flyweight objects are by definition value objects.
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*
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*/
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public class App {
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public static void main(String[] args) {
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AlchemistShop alchemistShop = new AlchemistShop();
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alchemistShop.enumerate();
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}
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}

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