Question

The DictionaryClient program featured in the class lecture also used the try-catch when creating a socket. Socket are auto-closeable and thus can use a try-with-resources instead. Edit the dictionary program to use try-with-resources instead.

package MySockets;

import java.net.*;
import java.io.*;

public class DictionaryClient {
  
   private static final String SERVER = "dict.org";
   private static final int PORT = 2628;
   private static final int TIMEOUT = 15000;

   public static void main(String[] args) {

       Socket    socket = null;
      
       try {
           socket = new Socket(SERVER, PORT);
           socket.setSoTimeout(TIMEOUT);

           System.out.print("Connected to Host : ");
           System.out.print(socket.getInetAddress() + " Port: ");
           System.out.println(socket.getPort());
           System.out.print("Connected from Host:" );
           System.out.print(socket.getLocalAddress() + " Port: ");
           System.out.println(socket.getLocalPort());
          
           InputStream in = socket.getInputStream();
           BufferedReader reader = new BufferedReader(new InputStreamReader(in, "UTF-8"));
          
           OutputStream out = socket.getOutputStream();
           Writer writer = new OutputStreamWriter(out, "UTF-8");
           writer = new BufferedWriter(writer);
          
           define(args[0], writer, reader);

       } catch (IOException ex) {
           System.err.println(ex);
       } finally {
           if(socket != null) {
               try {
                   socket.close();
               } catch(IOException e) {
                   System.out.println(e);
               }
           }              
       }
   }
  
   static void define(String word,
                   Writer writer,
                   BufferedReader reader) throws IOException {
       writer.write("SHOW DB\r\n");
       writer.write("DEFINE fd-eng-lat " + word + "\r\n");
       writer.flush();
      
       for(String line = reader.readLine(); line != null; line = reader.readLine()) {
           System.out.println(line);
           if(line.startsWith("250 ")) {
               writer.write("quit\r\n");
               writer.flush();
           }
       }
       return;
   }
}

Answer 1

Please find the answer below:

I have highlighted the changed part of the program.

package MySockets;

import java.net.*;
import java.io.*;

public class DictionaryClient {

    private static final String SERVER = "dict.org";
    private static final int PORT = 2628;
    private static final int TIMEOUT = 15000;

    public static void main(String[] args) {

        //no need of this line as we will use the tr with resource
        //Socket socket = null;

        //object is created using tr with resources and it implements the auto closeable so no need of the finally method
        try(Socket socket = new Socket(SERVER, PORT)) {
            socket.setSoTimeout(TIMEOUT);

            System.out.print("Connected to Host : ");
            System.out.print(socket.getInetAddress() + " Port: ");
            System.out.println(socket.getPort());
            System.out.print("Connected from Host:" );
            System.out.print(socket.getLocalAddress() + " Port: ");
            System.out.println(socket.getLocalPort());

            InputStream in = socket.getInputStream();
            BufferedReader reader = new BufferedReader(new InputStreamReader(in, "UTF-8"));

            OutputStream out = socket.getOutputStream();
            Writer writer = new OutputStreamWriter(out, "UTF-8");
            writer = new BufferedWriter(writer);

            define(args[0], writer, reader);

        } catch (IOException ex) {
            System.err.println(ex);
        }
        //fnally block is not required to close the socket
        /*
        finally{
            if(socket != null) {
               try {
                   socket.close();
               } catch(IOException e) {
                   System.out.println(e);
               }
           }        
        }
        */
      
    }

    static void define(String word,
                       Writer writer,
                       BufferedReader reader) throws IOException {
        writer.write("SHOW DB\r\n");
        writer.write("DEFINE fd-eng-lat " + word + "\r\n");
        writer.flush();

        for(String line = reader.readLine(); line != null; line = reader.readLine()) {
            System.out.println(line);
            if(line.startsWith("250 ")) {
                writer.write("quit\r\n");
                writer.flush();
            }
        }
        return;
    }
}

Answer 2

/**
 * Please find the updated solution with try with resources
 * I have bolded the required part and removed finally block
 */

package MySockets;

import java.net.*;
import java.io.*;

public class DictionaryClient {

    private static final String SERVER = "dict.org";
    private static final int PORT = 2628;
    private static final int TIMEOUT = 15000;

    public static void main(String[] args) {


        try (Socket socket = new Socket(SERVER, PORT)) {
            socket.setSoTimeout(TIMEOUT);

            System.out.print("Connected to Host : ");
            System.out.print(socket.getInetAddress() + " Port: ");
            System.out.println(socket.getPort());
            System.out.print("Connected from Host:");
            System.out.print(socket.getLocalAddress() + " Port: ");
            System.out.println(socket.getLocalPort());

            InputStream in = socket.getInputStream();
            BufferedReader reader = new BufferedReader(new InputStreamReader(in, "UTF-8"));

            OutputStream out = socket.getOutputStream();
            Writer writer = new OutputStreamWriter(out, "UTF-8");
            writer = new BufferedWriter(writer);

            define(args[0], writer, reader);

        } catch (IOException ex) {
            System.err.println(ex);
        }

// Removed finally block from here, it will be handled by we use try with resources

    }

    static void define(String word,
                       Writer writer,
                       BufferedReader reader) throws IOException {
        writer.write("SHOW DB\r\n");
        writer.write("DEFINE fd-eng-lat " + word + "\r\n");
        writer.flush();

        for (String line = reader.readLine(); line != null; line = reader.readLine()) {
            System.out.println(line);
            if (line.startsWith("250 ")) {
                writer.write("quit\r\n");
                writer.flush();
            }
        }
        return;
    }
}