Merge pull request #22 from darbyluv2code/feature/add-mediator-pattern

Add Mediator Pattern

Author: darbyluv2code

section-04-behavioral-design-patterns/17-mediator/pom.xml

@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <groupId>com.luv2code</groupId>
+    <artifactId>java-design-patterns</artifactId>
+    <version>1.0</version>
+
+    <properties>
+        <maven.compiler.source>25</maven.compiler.source>
+        <maven.compiler.target>25</maven.compiler.target>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+    </properties>
+
+</project>

section-04-behavioral-design-patterns/17-mediator/src/main/java/com/luv2code/designpatterns/behavioral/mediator/BillingService.java

@@ -0,0 +1,15 @@
+package com.luv2code.designpatterns.behavioral.mediator;
+
+/**
+ * Role: ConcreteColleague
+ *
+ * Handles billing-related support tickets.
+ */
+public class BillingService implements SupportService {
+
+    @Override
+    public void handleTicket(Ticket ticket) {
+        System.out.println("[BillingService] Processing refund request for "
+                + ticket.getCustomerName() + ": " + ticket.getMessage());
+    }
+}

section-04-behavioral-design-patterns/17-mediator/src/main/java/com/luv2code/designpatterns/behavioral/mediator/IssueType.java

@@ -0,0 +1,9 @@
+package com.luv2code.designpatterns.behavioral.mediator;
+
+/**
+ * Defines the supported ticket types.
+ */
+public enum IssueType {
+    BILLING,
+    TECHNICAL
+}

section-04-behavioral-design-patterns/17-mediator/src/main/java/com/luv2code/designpatterns/behavioral/mediator/MainApp.java

@@ -0,0 +1,47 @@
+package com.luv2code.designpatterns.behavioral.mediator;
+
+/**
+ * Demonstrates the Mediator pattern
+ *
+ * The SupportCenter (Mediator) coordinates communication between components.
+ */
+public class MainApp {
+
+    static void main() {
+
+        System.out.println("--- Demo: Support Ticket Routing ---");
+
+        NotificationSender notificationSender = new NotificationSender();
+        SupportCenter supportCenter = new SupportCenter(notificationSender);
+
+        supportCenter.registerService(IssueType.BILLING, new BillingService());
+        supportCenter.registerService(IssueType.TECHNICAL, new TechnicalService());
+
+        Ticket billingTicket = new Ticket(
+                IssueType.BILLING,
+                "Refund not processed",
+                "Alice"
+        );
+
+        Ticket technicalTicket = new Ticket(
+                IssueType.TECHNICAL,
+                "App is crashing",
+                "Bob"
+        );
+
+        supportCenter.submitTicket(billingTicket);
+
+        System.out.println();
+
+        supportCenter.submitTicket(technicalTicket);
+    }
+}
+
+
+
+
+
+
+
+
+

section-04-behavioral-design-patterns/17-mediator/src/main/java/com/luv2code/designpatterns/behavioral/mediator/NotificationSender.java

@@ -0,0 +1,14 @@
+package com.luv2code.designpatterns.behavioral.mediator;
+
+/**
+ * Helper class
+ *
+ * Sends a confirmation message after a ticket is processed.
+ */
+public class NotificationSender {
+
+    public void sendConfirmation(Ticket ticket) {
+        System.out.println("[Notification] Sent to " + ticket.getCustomerName()
+                + ": Your " + ticket.getType() + " ticket was received.");
+    }
+}

section-04-behavioral-design-patterns/17-mediator/src/main/java/com/luv2code/designpatterns/behavioral/mediator/SupportCenter.java

@@ -0,0 +1,48 @@
+package com.luv2code.designpatterns.behavioral.mediator;
+
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * Role: ConcreteMediator
+ *
+ * Coordinates ticket routing and customer notification.
+ */
+public class SupportCenter implements TicketMediator {
+
+    private Map<IssueType, SupportService> supportServices;
+    private NotificationSender notificationSender;
+
+    public SupportCenter(NotificationSender notificationSender) {
+        this.notificationSender = notificationSender;
+        supportServices = new HashMap<>();
+    }
+
+    public void registerService(IssueType issueType, SupportService supportService) {
+        supportServices.put(issueType, supportService);
+    }
+
+    @Override
+    public void submitTicket(Ticket ticket) {
+
+        System.out.println("[Mediator] Routing " + ticket.getType() + " ticket...");
+
+        SupportService supportService = supportServices.get(ticket.getType());
+
+        if (supportService == null) {
+            throw new IllegalStateException("No service registered for: " + ticket.getType());
+        }
+
+        supportService.handleTicket(ticket);
+        notificationSender.sendConfirmation(ticket);
+    }
+}
+
+
+
+
+
+
+
+
+

section-04-behavioral-design-patterns/17-mediator/src/main/java/com/luv2code/designpatterns/behavioral/mediator/SupportService.java

@@ -0,0 +1,11 @@
+package com.luv2code.designpatterns.behavioral.mediator;
+
+/**
+ * Role: Colleague
+ *
+ * Defines the common behavior for support services
+ */
+public interface SupportService {
+
+    void handleTicket(Ticket ticket);
+}

section-04-behavioral-design-patterns/17-mediator/src/main/java/com/luv2code/designpatterns/behavioral/mediator/TechnicalService.java

@@ -0,0 +1,15 @@
+package com.luv2code.designpatterns.behavioral.mediator;
+
+/**
+ * Role: ConcreteColleague
+ *
+ * Handles technical support tickets.
+ */
+public class TechnicalService implements SupportService {
+
+    @Override
+    public void handleTicket(Ticket ticket) {
+        System.out.println("[TechnicalService] Escalating to engineering for "
+                + ticket.getCustomerName() + ": " + ticket.getMessage());
+    }
+}

section-04-behavioral-design-patterns/17-mediator/src/main/java/com/luv2code/designpatterns/behavioral/mediator/Ticket.java

@@ -0,0 +1,31 @@
+package com.luv2code.designpatterns.behavioral.mediator;
+
+/**
+ * Domain object
+ *
+ * Represents a customer support ticket
+ */
+public class Ticket {
+
+    private IssueType type;
+    private String message;
+    private String customerName;
+
+    public Ticket(IssueType type, String message, String customerName) {
+        this.type = type;
+        this.message = message;
+        this.customerName = customerName;
+    }
+
+    public IssueType getType() {
+        return type;
+    }
+
+    public String getMessage() {
+        return message;
+    }
+
+    public String getCustomerName() {
+        return customerName;
+    }
+}

section-04-behavioral-design-patterns/17-mediator/src/main/java/com/luv2code/designpatterns/behavioral/mediator/TicketMediator.java

@@ -0,0 +1,11 @@
+package com.luv2code.designpatterns.behavioral.mediator;
+
+/**
+ * Role: Mediator
+ *
+ * Defines the method for submitting a ticket.
+ */
+public interface TicketMediator {
+
+    void submitTicket(Ticket ticket);
+}