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

/**
 *  Provides a static method to convert a relative url
 *  to an absolute url. But the algorithm is only
 *  approximate, and not complete
 *
 *  @author http://bumble.sf.net
 */
 
  
public class RelativeUrl extends Object
{
  //--------------------------------------------
  private static String NEWLINE = System.getProperty("line.separator");
  //--------------------------------------------
  private String text;  

  //--------------------------------------------
  public RelativeUrl()
  {
    this.text = "";
  }

  //--------------------------------------------
  public RelativeUrl(String sText)
  {
    this.text = sText;
  } 

  //--------------------------------------------
  /** resolve a relative url */
  public static String resolve(String sBaseUrl, String sRelativeUrl)
  {
    URL urlTest;
    URL urlBase;
    String sHost = "";
    String sBaseDirectory = "";

    try
    {
      //-- if the relative url has a protocol then it is
      //-- not relative an nothing further should be done.
      //--
      urlTest = new URL(sRelativeUrl);
      return sRelativeUrl;
    }
    catch (MalformedURLException e)
    {}

    try
    {
      //-- if the base url has no protocol then it is not
      //-- much good to us.
      urlBase = new URL(sBaseUrl);
    }
    catch (MalformedURLException e)
    {
      return sRelativeUrl;
    }

    sHost = urlBase.getProtocol() + "://" + urlBase.getHost();
    sBaseDirectory = sBaseUrl.substring(0, sBaseUrl.lastIndexOf("/") + 1);

    if (sRelativeUrl.trim().startsWith("/"))
    {
      return sHost + sRelativeUrl.trim();
    }
    else
    {
      return sBaseDirectory + sRelativeUrl.trim();
    }

    //return sRelativeUrl;
  } //-- method: resolve


  //--------------------------------------------
  /** a main method for testing */
  public static void main(String[] args) throws Exception
  {
    
    StringBuffer sbUsageMessage = new StringBuffer("");
    sbUsageMessage.append(
      "test usage: java RelativeUrl base-url relative-url");
    sbUsageMessage.append(NEWLINE);

    StringBuffer sbMessage = new StringBuffer("");


    if (args.length < 2)
    {	    
      System.out.println(sbUsageMessage);
      System.exit(-1);
    }

    String sBaseUrl = args[0];
    String sRelativeUrl = args[1];
        
    //System.out.print("Using  >");
    //System.out.println(sText);

    System.out.println("");
                                         
    System.out.print(".resolve()   >");
    System.out.println(RelativeUrl.resolve(sBaseUrl, sRelativeUrl));
 
  } //-- main()
  
} //-- RelativeUrl class