Java low level networking project (#770)

* made changes to java reflection

* removed redundant method makeSound in Animal abstract class

* added project for play-framework article

* added project for regex

* changed regex project from own model to core-java

* added project for routing in play

* made changes to regex project

* refactored code for REST API with Play project

* refactored student store indexing to zero base

* added unit tests, removed bad names

* added NIO Selector project under core-java module

* requested changes made

core-java/src/main/java/com/baeldung/java/networking/cookies/PersistentCookieStore.java

@@ -0,0 +1,56 @@
+package com.baeldung.java.networking.cookies;
+
+import java.net.*;
+import java.util.List;
+
+public class PersistentCookieStore implements CookieStore, Runnable {
+    CookieStore store;
+
+    public PersistentCookieStore() {
+        store = new CookieManager().getCookieStore();
+        // deserialize cookies into store
+        Runtime.getRuntime().addShutdownHook(new Thread(this));
+    }
+
+    @Override
+    public void run() {
+        // serialize cookies to persistent storage
+    }
+
+    @Override
+    public void add(URI uri, HttpCookie cookie) {
+        store.add(uri, cookie);
+
+    }
+
+    @Override
+    public List<HttpCookie> get(URI uri) {
+        // TODO Auto-generated method stub
+        return null;
+    }
+
+    @Override
+    public List<HttpCookie> getCookies() {
+        // TODO Auto-generated method stub
+        return null;
+    }
+
+    @Override
+    public List<URI> getURIs() {
+        // TODO Auto-generated method stub
+        return null;
+    }
+
+    @Override
+    public boolean remove(URI uri, HttpCookie cookie) {
+        // TODO Auto-generated method stub
+        return false;
+    }
+
+    @Override
+    public boolean removeAll() {
+        // TODO Auto-generated method stub
+        return false;
+    }
+
+}

core-java/src/main/java/com/baeldung/java/networking/cookies/ProxyAcceptCookiePolicy.java

@@ -0,0 +1,26 @@
+package com.baeldung.java.networking.cookies;
+
+import java.net.*;
+
+public class ProxyAcceptCookiePolicy implements CookiePolicy {
+    String acceptedProxy;
+
+    public ProxyAcceptCookiePolicy(String acceptedProxy) {
+        this.acceptedProxy = acceptedProxy;
+    }
+
+    public boolean shouldAccept(URI uri, HttpCookie cookie) {
+        String host;
+        try {
+            host = InetAddress.getByName(uri.getHost()).getCanonicalHostName();
+        } catch (UnknownHostException e) {
+            host = uri.getHost();
+        }
+
+        if (!HttpCookie.domainMatches(acceptedProxy, host)) {
+            return false;
+        }
+
+        return CookiePolicy.ACCEPT_ORIGINAL_SERVER.shouldAccept(uri, cookie);
+    }
+}

core-java/src/main/java/com/baeldung/java/networking/udp/EchoClient.java

@@ -0,0 +1,42 @@
+package com.baeldung.java.networking.udp;
+
+import java.io.IOException;
+import java.net.DatagramPacket;
+import java.net.DatagramSocket;
+import java.net.InetAddress;
+
+public class EchoClient {
+    private DatagramSocket socket;
+    private InetAddress address;
+
+    private byte[] buf;
+
+    public EchoClient() {
+        try {
+            socket = new DatagramSocket();
+            address = InetAddress.getByName("localhost");
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+
+    }
+
+    public String sendEcho(String msg) {
+        DatagramPacket packet = null;
+        try {
+            buf=msg.getBytes();
+            packet = new DatagramPacket(buf, buf.length, address, 4445);
+            socket.send(packet);
+            packet = new DatagramPacket(buf, buf.length);
+            socket.receive(packet);
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+        String received = new String(packet.getData(), 0, packet.getLength());
+        return received;
+    }
+
+    public void close() {
+        socket.close();
+    }
+}

core-java/src/main/java/com/baeldung/java/networking/udp/EchoServer.java

@@ -0,0 +1,42 @@
+package com.baeldung.java.networking.udp;
+
+import java.io.IOException;
+import java.net.DatagramPacket;
+import java.net.DatagramSocket;
+import java.net.InetAddress;
+
+public class EchoServer extends Thread {
+
+    protected DatagramSocket socket = null;
+    protected boolean running;
+    protected byte[] buf = new byte[256];
+
+    public EchoServer() throws IOException {
+        socket = new DatagramSocket(4445);
+    }
+
+    public void run() {
+        running = true;
+
+        while (running) {
+            try {
+
+                DatagramPacket packet = new DatagramPacket(buf, buf.length);
+                socket.receive(packet);
+                InetAddress address = packet.getAddress();
+                int port = packet.getPort();
+                packet = new DatagramPacket(buf, buf.length, address, port);
+                String received = new String(packet.getData(), 0, packet.getLength());
+                if (received.equals("end")) {
+                    running = false;
+                    continue;
+                }
+                socket.send(packet);
+            } catch (IOException e) {
+                e.printStackTrace();
+                running = false;
+            }
+        }
+        socket.close();
+    }
+}

core-java/src/main/java/com/baeldung/java/networking/udp/UDPTest.java

@@ -0,0 +1,33 @@
+package com.baeldung.java.networking.udp;
+
+import static org.junit.Assert.*;
+
+import java.io.IOException;
+
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+
+public class UDPTest {
+    EchoClient client = null;
+
+    @Before
+    public void setup() throws IOException {
+        new EchoServer().start();
+        client = new EchoClient();
+    }
+
+    @Test
+    public void whenCanSendAndReceivePacket_thenCorrect1() {
+        String echo = client.sendEcho("hello server");
+        assertEquals("hello server", echo);
+        echo = client.sendEcho("server is working");
+        assertFalse(echo.equals("hello server"));
+    }
+
+    @After
+    public void tearDown() {
+        client.sendEcho("end");
+        client.close();
+    }
+}

core-java/src/main/java/com/baeldung/java/nio/selector/EchoServer.java

@@ -1,15 +1,15 @@
 package com.baeldung.java.nio.selector;
 
-import java.io.File;
-import java.io.IOException;
-import java.net.InetSocketAddress;
-import java.nio.ByteBuffer;
-import java.nio.channels.SelectionKey;
-import java.nio.channels.Selector;
 import java.nio.channels.ServerSocketChannel;
 import java.nio.channels.SocketChannel;
-import java.util.Iterator;
+import java.nio.channels.Selector;
+import java.nio.channels.SelectionKey;
+import java.nio.ByteBuffer;
+import java.io.IOException;
 import java.util.Set;
+import java.util.Iterator;
+import java.net.InetSocketAddress;
+import java.io.File;
 
 public class EchoServer {
 
@@ -49,6 +49,7 @@ public class EchoServer {
         }
     }
 
+
     public static Process start() throws IOException, InterruptedException {
         String javaHome = System.getProperty("java.home");
         String javaBin = javaHome + File.separator + "bin" + File.separator + "java";
@@ -59,4 +60,4 @@ public class EchoServer {
 
         return builder.start();
     }
-}
+}