#3 add proxy pattern example into project

Author: ThanhPhiNgo

design-pattern/src/main/java/com/phint2/pattern/structural/proxy/protection/Client.java

@@ -0,0 +1,14 @@
+package com.phint2.pattern.structural.proxy.protection;
+
+public class Client {
+
+	public static void main(String[] args) {
+		UserService admin = new UserServiceProxy("phint", "admin");
+		admin.load();
+		admin.insert();
+
+		UserService customer = new UserServiceProxy("customer", "guest");
+		customer.load();
+		customer.insert();
+	}
+}

design-pattern/src/main/java/com/phint2/pattern/structural/proxy/protection/UserService.java

@@ -0,0 +1,7 @@
+package com.phint2.pattern.structural.proxy.protection;
+
+public interface UserService {
+
+	void load();
+	void insert();
+}

design-pattern/src/main/java/com/phint2/pattern/structural/proxy/protection/UserServiceImpl.java

@@ -0,0 +1,20 @@
+package com.phint2.pattern.structural.proxy.protection;
+
+public class UserServiceImpl implements UserService {
+
+	private String name;
+
+	public UserServiceImpl(String name) {
+		this.name = name;
+	}
+
+	@Override
+	public void load() {
+		System.out.println(name + " loaded");
+	}
+
+	@Override
+	public void insert() {
+		System.out.println(name + " inserted");
+	}
+}

design-pattern/src/main/java/com/phint2/pattern/structural/proxy/protection/UserServiceProxy.java

@@ -0,0 +1,31 @@
+package com.phint2.pattern.structural.proxy.protection;
+
+public class UserServiceProxy implements UserService {
+
+	private static final String ADMIN = "admin";
+	private String role;
+	private UserService userService;
+
+	public UserServiceProxy(String name, String role) {
+		this.role = role;
+		this.userService = new UserServiceImpl(name);
+	}
+
+	@Override
+	public void load() {
+		userService.load();
+	}
+
+	@Override
+	public void insert() {
+		if (isAdmin()) {
+			userService.insert();
+		} else {
+			throw new IllegalAccessError("Access denied");
+		}
+	}
+
+	private boolean isAdmin() {
+		return ADMIN.equalsIgnoreCase(this.role);
+	}
+}

design-pattern/src/main/java/com/phint2/pattern/structural/proxy/virtual/Client.java

@@ -0,0 +1,17 @@
+package com.phint2.pattern.structural.proxy.virtual;
+
+public class Client {
+
+	public static void main(String[] args) {
+		System.out.println("Init proxy image: ");
+		ProxyImage proxyImage = new ProxyImage("abc.com");
+
+		System.out.println("---");
+		System.out.println("Call real service 1st: ");
+		proxyImage.showImage();
+
+		System.out.println("---");
+		System.out.println("Call real service 2nd: ");
+		proxyImage.showImage();
+	}
+}

design-pattern/src/main/java/com/phint2/pattern/structural/proxy/virtual/Image.java

@@ -0,0 +1,6 @@
+package com.phint2.pattern.structural.proxy.virtual;
+
+public interface Image {
+
+	void showImage();
+}

design-pattern/src/main/java/com/phint2/pattern/structural/proxy/virtual/ProxyImage.java

@@ -0,0 +1,22 @@
+package com.phint2.pattern.structural.proxy.virtual;
+
+public class ProxyImage implements Image {
+
+	private RealImage realImage;
+	private String url;
+
+	public ProxyImage(String url) {
+		this.url = url;
+		System.out.println("Image unloaded: " + this.url);
+	}
+
+	@Override
+	public void showImage() {
+		if (null == realImage) {
+			realImage = new RealImage(this.url);
+		} else {
+			System.out.println("Image already existed: " + this.url);
+		}
+		realImage.showImage();
+	}
+}

design-pattern/src/main/java/com/phint2/pattern/structural/proxy/virtual/RealImage.java

@@ -0,0 +1,16 @@
+package com.phint2.pattern.structural.proxy.virtual;
+
+public class RealImage implements Image {
+
+	private String url;
+
+	public RealImage(String url) {
+		this.url = url;
+		System.out.println("Image loaded: " + this.url);
+	}
+
+	@Override
+	public void showImage() {
+		System.out.println("Image showed: " + this.url);
+	}
+}