Merge branch 'PortChange' into 'main'

Portchange

Closes #64

See merge request cse1105/2025-2026/teams/csep-team-76!62

server/src/main/java/server/PortChecker.java

@@ -0,0 +1,51 @@
+package server;
+
+import java.io.IOException;
+import java.net.ServerSocket;
+import java.util.Scanner;
+
+public class PortChecker {
+    private static final int defaultPort = 8080;
+    private static final int lastValidPort = 65535;
+
+
+    /**
+     * Finds a free port to launch the program on.
+     * made with the help of https://medium.com/@rrlinus5/find-available-port-in-your-system-java-f532ee48c5b3
+     * @return the port that will be used to launch the program
+     * @throws IOException when no available port is found
+     */
+    public int findFreePort() throws IOException {
+        if(isPortAvailable(defaultPort)){
+            return defaultPort;
+        }
+
+        System.out.println("Please enter the port number you want to use");
+        Scanner portScanner = new Scanner(System.in);
+        while(true){
+            int port = portScanner.nextInt();
+
+            if(port > 0 && port <=lastValidPort){ //range of valid ports
+                isPortAvailable(port);
+                return port;
+            }
+            else {
+                System.out.println("Try a different port:");
+            }
+        }
+    }
+
+    /**
+     * Checks whether a port is actually available.
+     * @param port the number of the port that's being checker
+     * @return whether the port was available
+     */
+    public boolean isPortAvailable(int port){
+        try(ServerSocket socket = new ServerSocket(port)){
+            return true;
+        }
+        catch(IOException i) {
+            return false;
+        }
+    }
+}

server/src/main/java/server/ServerPortCustomizer.java

@@ -0,0 +1,27 @@
+package server;
+
+import org.springframework.boot.web.server.ConfigurableWebServerFactory;
+import org.springframework.boot.web.server.WebServerFactoryCustomizer;
+import org.springframework.stereotype.Component;
+
+@Component
+public class ServerPortCustomizer
+        implements WebServerFactoryCustomizer<ConfigurableWebServerFactory>{
+    /**
+     * Changes the port that will be used to launch the program.
+     * made with the help of: https://www.baeldung.com/spring-boot-change-port
+     * @param factory
+     */
+    @Override
+    public void customize(ConfigurableWebServerFactory factory) {
+        try {
+            PortChecker portChecker = new PortChecker();
+            int port = portChecker.findFreePort();
+            factory.setPort(port);
+            System.out.println("Server starts on port: " + port);
+        }
+        catch (Exception e) {
+            throw new RuntimeException("Failed to find a free port", e);
+        }
+    }
+}

server/src/test/java/server/PortCheckerTest.java

@@ -0,0 +1,61 @@
+package server;
+
+import org.junit.jupiter.api.Test;
+import java.io.IOException;
+import java.net.ServerSocket;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class PortCheckerTest {
+    @Test
+    void portAvailable() {
+        PortChecker checker = new PortChecker();
+
+        int port = 0; //will find a random available port
+        boolean available = checker.isPortAvailable(port);
+
+        assertTrue(available);
+    }
+    @Test
+    void portNotAvailable(){
+        try  {
+            ServerSocket socket = new ServerSocket(0);
+            int usedPort = socket.getLocalPort();
+
+            PortChecker checker = new PortChecker();
+            boolean notFree = checker.isPortAvailable(usedPort);
+            assertFalse(notFree);
+        }
+        catch (IOException e) {
+            throw new RuntimeException(e);
+        }
+    }
+    @Test
+    void invalidPort(){
+        PortChecker checker = new PortChecker();
+
+        assertThrows(IllegalArgumentException.class, ()-> {
+            checker.isPortAvailable(-1);
+                }
+        );
+        assertThrows(IllegalArgumentException.class, ()-> {
+            checker.isPortAvailable(65536);
+                }
+        );
+    }
+    @Test
+    void findFreePort() throws IOException {
+        PortChecker checker = new PortChecker();
+
+        int port = checker.findFreePort();
+        int defaultPort = 8080;
+        int lastPort = 8090;
+
+        boolean greaterOrEqual = port >= defaultPort;
+        boolean lessOrEqual = port <= lastPort;
+        boolean inRange = greaterOrEqual && lessOrEqual;
+        boolean isItFree = checker.isPortAvailable(port);
+
+        assertTrue(inRange);
+    }
+}