Merge branch 'release/design-pattern-v3.0.0-rl-211022-implement-chain-of-responsibility-pattern'

Author: ThanhPhiNgo

README.md

@@ -70,6 +70,19 @@ Reference: https://gpcoder.com/4626-huong-dan-java-design-pattern-flyweight/
 
 ### Proxy
 
-https://gpcoder.com/4644-huong-dan-java-design-pattern-proxy/
+Reference: https://gpcoder.com/4644-huong-dan-java-design-pattern-proxy/
 
 > Review: Useful for lazy loading
+
+<hr/>
+
+## Behavior
+
+### Chain of Responsibility
+
+Reference: https://gpcoder.com/4665-huong-dan-java-design-pattern-chain-of-responsibility/
+
+> Review:
+>
+> -   Suitable for create and push Alert through applications (tools) by level
+> -   Summary: Execute an action by level chain, which has corresponding condition for each level

design-pattern/pom.xml

@@ -6,7 +6,7 @@
 
     <groupId>com.phint2</groupId>
     <artifactId>design-pattern</artifactId>
-    <version>2.6.0</version>
+    <version>3.0.0</version>
 
     <properties>
         <maven.compiler.source>8</maven.compiler.source>

design-pattern/src/main/java/com/phint2/pattern/behavioral/cor/leaverequest/Approver.java

@@ -0,0 +1,28 @@
+package com.phint2.pattern.behavioral.cor.leaverequest;
+
+public abstract class Approver {
+
+	protected Approver nextApprover;
+
+	public void approveLeave(LeaveRequest request) {
+		System.out.println("Checking permission for " + this.getClass().getSimpleName());
+
+		if (this.canApprove(request.getDays())) {
+			this.doApproving(request);
+		} else if (nextApprover != null) {
+			nextApprover.approveLeave(request);
+		}
+	}
+
+	public void setNext(Approver approver) {
+		this.nextApprover = approver;
+	}
+
+	protected void doApproving(LeaveRequest request) {
+		System.out.println("Leave request approved for " + request.getDays() + " days by " + getTitle());
+	}
+
+	protected abstract String getTitle();
+
+	protected abstract boolean canApprove(int numberOfDays);
+}

design-pattern/src/main/java/com/phint2/pattern/behavioral/cor/leaverequest/ApproverPermission.java

@@ -0,0 +1,18 @@
+package com.phint2.pattern.behavioral.cor.leaverequest;
+
+public enum ApproverPermission {
+
+	Supervisor(3),
+	DeliveryManage(5),
+	Director(Integer.MAX_VALUE);
+
+	private int days;
+
+	private ApproverPermission(int days) {
+		this.days = days;
+	}
+
+	public int getDays() {
+		return this.days;
+	}
+}

design-pattern/src/main/java/com/phint2/pattern/behavioral/cor/leaverequest/Client.java

@@ -0,0 +1,13 @@
+package com.phint2.pattern.behavioral.cor.leaverequest;
+
+public class Client {
+
+	public static void main(String[] args) {
+
+		LeaveRequestWorkFlow.getApprover().approveLeave(new LeaveRequest(8));
+		System.out.println("---");
+		LeaveRequestWorkFlow.getApprover().approveLeave(new LeaveRequest(2));
+		System.out.println("---");
+		LeaveRequestWorkFlow.getApprover().approveLeave(new LeaveRequest(5));
+	}
+}

design-pattern/src/main/java/com/phint2/pattern/behavioral/cor/leaverequest/DeliveryManage.java

@@ -0,0 +1,14 @@
+package com.phint2.pattern.behavioral.cor.leaverequest;
+
+public class DeliveryManage extends Approver {
+
+	@Override
+	protected String getTitle() {
+		return "Delivery Manager";
+	}
+
+	@Override
+	protected boolean canApprove(int numberOfDays) {
+		return numberOfDays <= ApproverPermission.DeliveryManage.getDays();
+	}
+}

design-pattern/src/main/java/com/phint2/pattern/behavioral/cor/leaverequest/Director.java

@@ -0,0 +1,13 @@
+package com.phint2.pattern.behavioral.cor.leaverequest;
+
+public class Director extends Approver {
+	@Override
+	protected String getTitle() {
+		return "Director";
+	}
+
+	@Override
+	protected boolean canApprove(int numberOfDays) {
+		return numberOfDays > ApproverPermission.DeliveryManage.getDays();
+	}
+}

design-pattern/src/main/java/com/phint2/pattern/behavioral/cor/leaverequest/LeaveRequest.java

@@ -0,0 +1,14 @@
+package com.phint2.pattern.behavioral.cor.leaverequest;
+
+public class LeaveRequest {
+
+	private int days;
+
+	public LeaveRequest(int days) {
+		this.days = days;
+	}
+
+	public int getDays() {
+		return this.days;
+	}
+}

design-pattern/src/main/java/com/phint2/pattern/behavioral/cor/leaverequest/LeaveRequestWorkFlow.java

@@ -0,0 +1,14 @@
+package com.phint2.pattern.behavioral.cor.leaverequest;
+
+public class LeaveRequestWorkFlow {
+
+	public static Approver getApprover() {
+		Approver supervisor = new Supervisor();
+		Approver manager = new DeliveryManage();
+		Approver director = new Director();
+
+		supervisor.setNext(manager);
+		manager.setNext(director);
+		return supervisor;
+	}
+}

design-pattern/src/main/java/com/phint2/pattern/behavioral/cor/leaverequest/Supervisor.java

@@ -0,0 +1,14 @@
+package com.phint2.pattern.behavioral.cor.leaverequest;
+
+public class Supervisor extends Approver {
+
+	@Override
+	protected String getTitle() {
+		return "Supervisor";
+	}
+
+	@Override
+	protected boolean canApprove(int numberOfDays) {
+		return numberOfDays <= ApproverPermission.Supervisor.getDays();
+	}
+}

design-pattern/src/main/java/com/phint2/pattern/behavioral/cor/logger/AppLogger.java

@@ -0,0 +1,12 @@
+package com.phint2.pattern.behavioral.cor.logger;
+
+public class AppLogger {
+
+	public static Logger getLogger() {
+
+		Logger consoleLogger = new ConsoleLogger(LogLevel.DEBUG);
+		Logger fileLogger = consoleLogger.setNext(new FileLogger(LogLevel.ERROR));
+		fileLogger.setNext(new MailLogger(LogLevel.FATAL));
+		return consoleLogger;
+	}
+}

design-pattern/src/main/java/com/phint2/pattern/behavioral/cor/logger/Client.java

@@ -0,0 +1,23 @@
+package com.phint2.pattern.behavioral.cor.logger;
+
+/*
+* Chain of Responsibility Pattern Example
+* */
+public class Client {
+
+	public static void main(String[] args) {
+
+		// Build the chain of responsibility
+		Logger logger = AppLogger.getLogger();
+
+		// Handled by ConsoleLogger since the console has a LogLevel of DEBUG
+		logger.log(LogLevel.INFO, "Info message");
+		logger.log(LogLevel.DEBUG, "Debug message");
+
+		// Handled by ConsoleLogger and FileLogger
+		logger.log(LogLevel.ERROR, "Error message");
+
+		// Handled by ConsoleLogger, FileLogger, MailLogger
+		logger.log(LogLevel.FATAL, "Fatal message");
+	}
+}

design-pattern/src/main/java/com/phint2/pattern/behavioral/cor/logger/ConsoleLogger.java

@@ -0,0 +1,13 @@
+package com.phint2.pattern.behavioral.cor.logger;
+
+public class ConsoleLogger extends Logger {
+
+	public ConsoleLogger(LogLevel logLevel) {
+		super(logLevel);
+	}
+
+	@Override
+	protected void writeMessage(String message) {
+		System.out.println("Console logger: " + message);
+	}
+}

design-pattern/src/main/java/com/phint2/pattern/behavioral/cor/logger/FileLogger.java

@@ -0,0 +1,13 @@
+package com.phint2.pattern.behavioral.cor.logger;
+
+public class FileLogger extends Logger {
+
+	public FileLogger(LogLevel logLevel) {
+		super(logLevel);
+	}
+
+	@Override
+	protected void writeMessage(String message) {
+		System.out.println("File logger: " + message);
+	}
+}

design-pattern/src/main/java/com/phint2/pattern/behavioral/cor/logger/LogLevel.java

@@ -0,0 +1,22 @@
+package com.phint2.pattern.behavioral.cor.logger;
+
+public enum LogLevel {
+
+	NONE(0),
+	INFO(1),
+	DEBUG(2),
+	WARNING(4),
+	ERROR(8),
+	FATAL(16),
+	ALL(32);
+
+	private int level;
+
+	private LogLevel(int level) {
+		this.level = level;
+	}
+
+	public int getLevel() {
+		return level;
+	}
+}

design-pattern/src/main/java/com/phint2/pattern/behavioral/cor/logger/Logger.java

@@ -0,0 +1,28 @@
+package com.phint2.pattern.behavioral.cor.logger;
+
+public abstract class Logger {
+
+	protected LogLevel logLevel;
+	protected Logger nextLogger; // The next Handler in the chain
+
+	public Logger(LogLevel logLevel) {
+		this.logLevel = logLevel;
+	}
+
+	// Set the next logger to make a list/chain of Handlers.
+	public Logger setNext(Logger nextLogger) {
+		this.nextLogger = nextLogger;
+		return nextLogger;
+	}
+
+	public void log(LogLevel severity, String message) {
+		if (this.logLevel.getLevel() <= severity.getLevel()) {
+			writeMessage(message);
+		}
+		if (nextLogger != null) {
+			nextLogger.log(severity, message);
+		}
+	}
+
+	protected abstract void writeMessage(String message);
+}

design-pattern/src/main/java/com/phint2/pattern/behavioral/cor/logger/MailLogger.java

@@ -0,0 +1,13 @@
+package com.phint2.pattern.behavioral.cor.logger;
+
+public class MailLogger extends Logger {
+
+	public MailLogger(LogLevel logLevel) {
+		super(logLevel);
+	}
+
+	@Override
+	protected void writeMessage(String message) {
+		System.out.println("Mail logger: " + message);
+	}
+}