package networking;

import java.awt.Font;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.UnsupportedEncodingException;

import java.net.URL;
import java.net.MalformedURLException;

import java.util.Properties;

import javax.swing.JApplet;
import javax.swing.JButton;
import javax.swing.JPanel;

/**
 *   Applet to perform a query against the Lycos search engine.
 */
public class QueryApplet extends JApplet
{
  public void init()
  {
    if (!m_laidOut)
    {
      JPanel contentPanel = new JPanel();
      setContentPane(contentPanel);

      // Add the button to the applet's content pane
      contentPanel.add(m_button);
      // Set attributes of the button
      m_button.setFont( new Font("SansSerif", Font.PLAIN, 14) );
      m_button.addActionListener( new ActionListener()
        {
          public void actionPerformed(ActionEvent e)
          {
            performQuery();
          }
        }
      );
      
      m_laidOut = true;
    }
  }
  
  /**
   *   Perform the query, firing up a new browser window.
   */
  private void performQuery()
  {
    try
    {
      // Create the base URL
      URL url = new URL("http://maps.google.com/maps");
      
      // Create the set of properties needed for the query
      Properties props = new Properties();
      props.put("f", "q");
      props.put("hl", "en");
      props.put("q", "Rivier College, Nashua, NH 03060");
      props.put("ie", "UTF8");
      props.put("z", "12");
      props.put("om", "1");
      try
      {
        // Create the final query URL
        url = URLQuery.createQuery(url, props);
System.out.println("Showing document: " + url);
        getAppletContext().showDocument(url, "_blank");
      } 
      catch (UnsupportedEncodingException ex)
      {
        ex.printStackTrace();
      } 
    }
    catch (MalformedURLException e)
    {
      e.printStackTrace();
    }
  }
  
  //// Private data ////
  private boolean m_laidOut = false;
  
  private JButton  m_button = new JButton("Google Maps Query");
}

package networking;

import java.io.UnsupportedEncodingException;
import java.net.URL;
import java.net.URLEncoder;
import java.net.MalformedURLException;

import java.util.Enumeration;
import java.util.Properties;

/**
 *   Class to create a URL to perform a CGI query against a web server.
 */
public class URLQuery
{
  /**
   *   Creates a URL query from the base URL and the set of properties.
   */
  public static URL createQuery(URL baseURL, Properties params)
      throws MalformedURLException, UnsupportedEncodingException
  {
    // Queries use the URL followed by a '?' character
    String file = baseURL.getFile() + "?";
    
    // And then append the query parameters to the URL string
    Enumeration e = params.propertyNames();
    int count = 0;
    while ( e.hasMoreElements() )
    {
      String propertyName = (String) e.nextElement();
      propertyName = URLEncoder.encode(propertyName, "UTF-8");
      if (count > 0)
        file += "&";        // Separate parameters with '&' character
      file += propertyName;
      String propertyValue = params.getProperty(propertyName);
      if (propertyValue != null)
      {
        propertyValue = URLEncoder.encode(propertyValue, "UTF-8");
        file += "=" + propertyValue;
      }
      count++;
    }
    
    return new URL(baseURL.getProtocol(), 
                   baseURL.getHost(),
                   baseURL.getPort(), 
                   file);
  }
  
  private URLQuery()
  {
    // Disable constructor
  }
}

package networking;

import java.net.URL;
import java.net.URLConnection;

import java.io.BufferedReader;
import java.io.InputStreamReader;

/**
*   Application to read text from a URL specified in the 
*   first command line argument, using a URLConnection
*   (Note that this is NOT a Reader in the same sense as BufferedReader.)
*/
public class URLConnectionReader
{
    public static void main(String[] args) throws Exception
    {
        URL url = new URL(args[0]);
        URLConnection conn = url.openConnection();
        BufferedReader reader = new BufferedReader(
                                        new InputStreamReader(
                                                conn.getInputStream()));
        try
        {
            String line = null;
            while (true)
            {
                line = reader.readLine();
                if (line == null)
                    break;
                System.out.println(line);
            }
        }
        finally
        {
            reader.close();
        }
    }
}

package networking;

import java.net.URL;
import java.net.URLConnection;
import java.net.URLEncoder;

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.PrintWriter;

public class Reverse
{
    public static void main(String[] args) throws Exception
    {
        if (args.length < 1)
        {
            System.err.println("Usage: java networking.Reverse " +
                               "<string-to-reverse>");
            return;                               
        }
        
        // Translate into x-www-form-urlencoded format:
        String reverseMe = URLEncoder.encode(args[0]);
        
        // Open connection to URL
        URL url = new URL("http://java.sun.com/cgi-bin/backwards");
        URLConnection conn = url.openConnection();
        // Set connection so it can do output
        conn.setDoOutput(true);
        
        // Provide input to server using the output stream.
        PrintWriter out = new PrintWriter(conn.getOutputStream());
        try
        {
            out.println("string=" + reverseMe);
        }
        finally
        {
            out.close();
        }
        
        // Read response from server
        BufferedReader in = new BufferedReader(
                                    new InputStreamReader(
                                            conn.getInputStream()));
        String line = null;
        try
        {
            while (true)
            {
                line = in.readLine();
                if (line == null)
                    break;
                System.out.println(line);
            }
        }
        finally
        {
            in.close();
        }
    }
}