Merge branch 'release/design-pattern-v2.5.0-rl-211014-implement-flyweight-pattern'

Author: ThanhPhiNgo

README.md

@@ -62,3 +62,8 @@ Reference: https://gpcoder.com/4574-huong-dan-java-design-pattern-decorator/
 ### Facade
 
 Reference: https://gpcoder.com/4604-huong-dan-java-design-pattern-facade/
+
+### Flyweight
+
+Reference: https://gpcoder.com/4626-huong-dan-java-design-pattern-flyweight/
+Review: Good for create character in game

design-pattern/pom.xml

@@ -6,7 +6,7 @@
 
     <groupId>com.phint2</groupId>
     <artifactId>design-pattern</artifactId>
-    <version>2.4.0</version>
+    <version>2.5.0</version>
 
     <properties>
         <maven.compiler.source>8</maven.compiler.source>

design-pattern/src/main/java/com/phint2/pattern/structural/flyweight/AppGame.java

@@ -0,0 +1,47 @@
+package com.phint2.pattern.structural.flyweight;
+
+import java.time.Duration;
+import java.util.ArrayList;
+import java.util.List;
+
+/*
+ * Client
+ * */
+public class AppGame {
+
+	private static List<ISoldier> soldiers = new ArrayList<>();
+
+	public static void main(String[] args) {
+		long startTime = System.currentTimeMillis();
+		createSoldier(5, "Yuri", 1);
+		createSoldier(5, "Spy", 1);
+		createSoldier(3, "Spy", 3);
+		createSoldier(2, "Yuri", 2);
+		long endTime = System.currentTimeMillis();
+		System.out.println("---");
+		System.out.println("Total soldiers made: " + soldiers.size());
+		System.out.println("Total time worked: " + Duration.ofMillis(endTime - startTime));
+		System.out.println("Total type of soldiers made: " + SoldierFactory.getTotalSoldiers());
+	}
+
+	private static void createSoldier(int numberOfSoldier, String soldierName, int numberOfStart) {
+
+		for (int i = 0; i < numberOfSoldier; i++) {
+			Context start = new Context("Soldier" + (soldiers.size() + 1), numberOfStart);
+			ISoldier soldier = SoldierFactory.createSoldier(soldierName);
+			soldier.promote(start);
+			soldiers.add(soldier);
+		}
+	}
+}
+
+
+
+
+
+
+
+
+
+
+

design-pattern/src/main/java/com/phint2/pattern/structural/flyweight/Context.java

@@ -0,0 +1,23 @@
+package com.phint2.pattern.structural.flyweight;
+
+/*
+* Extrinsic State
+* */
+public class Context {
+
+	private String id;
+	private int start;
+
+	public Context(String id, int start) {
+		this.id = id;
+		this.start = start;
+	}
+
+	public String getId() {
+		return id;
+	}
+
+	public int getStart() {
+		return start;
+	}
+}

design-pattern/src/main/java/com/phint2/pattern/structural/flyweight/ISoldier.java

@@ -0,0 +1,9 @@
+package com.phint2.pattern.structural.flyweight;
+
+/*
+* Flyweight
+* */
+public interface ISoldier {
+
+	void promote(Context context);
+}

design-pattern/src/main/java/com/phint2/pattern/structural/flyweight/Soldier.java

@@ -0,0 +1,19 @@
+package com.phint2.pattern.structural.flyweight;
+
+/*
+* Concrete Flyweight
+* */
+public class Soldier implements ISoldier {
+
+	private final String name; // Intrinsic State
+
+	public Soldier(String name) {
+		this.name = name;
+		System.out.println("Solider is created! - " + name);
+	}
+
+	@Override
+	public void promote(Context context) {
+		System.out.println(name + " " + context.getId() + " promoted " + context.getStart());
+	}
+}

design-pattern/src/main/java/com/phint2/pattern/structural/flyweight/SoldierFactory.java

@@ -0,0 +1,38 @@
+package com.phint2.pattern.structural.flyweight;
+
+import java.util.HashMap;
+import java.util.Map;
+
+/*
+ * Flyweight Factory
+ * */
+public class SoldierFactory {
+
+	private static final Map<String, ISoldier> soldiers = new HashMap<>();
+
+	private SoldierFactory() {
+		throw new IllegalStateException();
+	}
+
+	public static synchronized ISoldier createSoldier(String name) {
+		ISoldier soldier = soldiers.get(name);
+		if (null == soldier) {
+			waitForCreateASoldier();
+			soldier = new Soldier(name);
+			soldiers.put(name, soldier);
+		}
+		return soldier;
+	}
+
+	public static synchronized int getTotalSoldiers() {
+		return soldiers.size();
+	}
+
+	private static void waitForCreateASoldier() {
+		try {
+			Thread.sleep(3000);
+		} catch (InterruptedException e) {
+			e.printStackTrace();
+		}
+	}
+}