added flyweight sample

flyweight/pom.xml

@@ -0,0 +1,23 @@
+<?xml version="1.0"?>
+<project xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd" xmlns="http://maven.apache.org/POM/4.0.0"
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
+  <modelVersion>4.0.0</modelVersion>
+  <parent>
+    <groupId>com.iluwatar</groupId>
+    <artifactId>java-design-patterns</artifactId>
+    <version>1.0-SNAPSHOT</version>
+  </parent>
+  <groupId>com.iluwatar</groupId>
+  <artifactId>flyweight</artifactId>
+  <version>1.0-SNAPSHOT</version>
+  <name>flyweight</name>
+  <url>http://maven.apache.org</url>
+  <dependencies>
+    <dependency>
+      <groupId>junit</groupId>
+      <artifactId>junit</artifactId>
+      <version>3.8.1</version>
+      <scope>test</scope>
+    </dependency>
+  </dependencies>
+</project>

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

@@ -0,0 +1,49 @@
+package com.iluwatar;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class AlchemistShop {
+
+	List<Potion> topShelf;
+	List<Potion> bottomShelf;
+	
+	public AlchemistShop() {
+		topShelf = new ArrayList<>();
+		bottomShelf = new ArrayList<>();
+		fillShelves();
+	}
+
+	private void fillShelves() {
+		topShelf.add(new InvisibilityPotion());
+		topShelf.add(new InvisibilityPotion());
+		topShelf.add(new StrengthPotion());
+		topShelf.add(new HealingPotion());
+		topShelf.add(new InvisibilityPotion());
+		topShelf.add(new StrengthPotion());
+		topShelf.add(new HealingPotion());
+		topShelf.add(new HealingPotion());
+		
+		bottomShelf.add(new PoisonPotion());
+		bottomShelf.add(new PoisonPotion());
+		bottomShelf.add(new PoisonPotion());
+		bottomShelf.add(new HolyWaterPotion());
+		bottomShelf.add(new HolyWaterPotion());
+	}
+	
+	public void enumerate() {
+
+		System.out.println("Enumerating top shelf potions\n");
+		
+		for (Potion p: topShelf) {
+			p.drink();
+		}
+		
+		System.out.println("\nEnumerating bottom shelf potions\n");
+		
+		for (Potion p: bottomShelf) {
+			p.drink();
+		}
+		
+	}
+}

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

@@ -0,0 +1,10 @@
+package com.iluwatar;
+
+public class App 
+{
+    public static void main( String[] args )
+    {
+    	AlchemistShop alchemistShop = new AlchemistShop();
+    	alchemistShop.enumerate();
+    }
+}

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

@@ -0,0 +1,10 @@
+package com.iluwatar;
+
+public class HealingPotion implements Potion {
+
+	@Override
+	public void drink() {
+		System.out.println("You feel healed.");
+	}
+
+}

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

@@ -0,0 +1,10 @@
+package com.iluwatar;
+
+public class HolyWaterPotion implements Potion {
+
+	@Override
+	public void drink() {
+		System.out.println("You feel blessed.");
+	}
+
+}

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

@@ -0,0 +1,10 @@
+package com.iluwatar;
+
+public class InvisibilityPotion implements Potion {
+
+	@Override
+	public void drink() {
+		System.out.println("You become invisible.");
+	}
+
+}

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

@@ -0,0 +1,10 @@
+package com.iluwatar;
+
+public class PoisonPotion implements Potion {
+
+	@Override
+	public void drink() {
+		System.out.println("Urgh! This is poisonous.");
+	}
+
+}

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

@@ -0,0 +1,7 @@
+package com.iluwatar;
+
+public interface Potion {
+
+	public void drink();
+	
+}

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

@@ -0,0 +1,39 @@
+package com.iluwatar;
+
+import java.util.EnumMap;
+
+public class PotionFactory {
+
+	private EnumMap<PotionType, Potion> potions;
+	
+	public PotionFactory() {
+		potions = new EnumMap<>(PotionType.class);
+	}
+	
+	Potion createPotion(PotionType type) {
+		Potion potion = potions.get(type);
+		if (potion == null) {
+			switch (type) {
+			case HEALING:
+				potion = new HealingPotion();
+				break;
+			case HOLY_WATER:
+				potion = new HolyWaterPotion();
+				break;
+			case INVISIBILITY:
+				potion = new InvisibilityPotion();
+				break;
+			case POISON:
+				potion = new PoisonPotion();
+				break;
+			case STRENGTH:
+				potion = new StrengthPotion();
+				break;
+			default:
+				break;
+			}
+		}
+		return potion;
+	}
+	
+}

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

@@ -0,0 +1,11 @@
+package com.iluwatar;
+
+public enum PotionType {
+
+	HEALING,
+	INVISIBILITY,
+	STRENGTH,
+	HOLY_WATER,
+	POISON;
+	
+}

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

@@ -0,0 +1,10 @@
+package com.iluwatar;
+
+public class StrengthPotion implements Potion {
+
+	@Override
+	public void drink() {
+		System.out.println("You feel strong.");
+	}
+
+}