Content of FetchURL.java extracted from checkweb.jar

//
// fetchURL: class used to check a URL via http connection
//
// used by checkweb.java
// requires HttpConnection.java
//
// Only textfiles are fetched, other content-types are ignored
//
// version 0.1
// version 0.2 updated in order to use the class URL instead of class URI, updated naming of files in cache
// version 0.3 changed the name files are named, see tag TAG-0001
// version 0.4: adapted to package concept
package checkweb;
 
import javax.swing.JTable;
import java.io.*;
import java.net.*;
 
public class FetchURL extends Thread {
 
 String urlName;
 JTable table;
 int row;
 OutputStream f, content = null;
 
// constructor
 public FetchURL(String urlName, int row, JTable table) {
  this.urlName=urlName;
  this.table = table;
  this.row = row;
  start();
 }
 
 synchronized void println(String s) {
	if (table == null)
		System.out.println(urlName+"--->"+s);
	else table.setValueAt(s,row,1);
 }
 
 public void run() {
  try{
		HttpConnection server = new HttpConnection(urlName);
	   int responseCode = server.getResponseCode();
	   if (responseCode != 200) {
			println("HTTP response code: " + 
			   String.valueOf(responseCode)+" "+server.getResponseMessage());
			server.close();
			return;
	   }
	   if ((server.getContentType()!=null)&&(!server.getContentType().startsWith("text")))
		   {	println ("Content type is different from <text>"); 
	   			server.close();
				return; }
	   println("server contacted");
	   long webtime = server.getLastModified();
	   if (webtime == 0)
	   { webtime = System.currentTimeMillis();
	   }
//	   Date time = new Date(webtime); System.out.println(time.toString());
	   URL url = new URL(urlName);
	   String fileName = url.getPath();
	   if (fileName.length() == 0) fileName = "/"; // small correction, in case filename is empty
	   if (fileName.endsWith("/"))
	   { fileName += "index.html";
	   }
	   File dir =  new File(Main.cache+"/"+url.getHost());
	   if (!dir.exists()) 	dir.mkdir();
 
// TAG-0001
//	   fileName = dir.toString()+fileName.charAt(0)+fileName.substring(1).replace('/','.')+((url.getQuery()!=null ? "^"+url.getQuery().hashCode() : ""));
	   fileName = dir.toString()+fileName.charAt(0)+fileName.substring(1).replace('/','.')+((url.getQuery()!=null ? "^"+url.getQuery().replace('*','.').replace(':','.')+".html" : ""));
 
	   File target = new File(fileName);
	   LineNumberReader in = null; boolean equal = false;
	   if (target.exists())
	   {    if (webtime == target.lastModified()) { println("No changes"); return; }
			in = new LineNumberReader(new FileReader(target));
			equal = true; // later on a check is performed!
	   };
 
 
       File tempFile = File.createTempFile("check",null,dir);
	   PrintWriter outStream = new PrintWriter(new FileWriter(tempFile));
	   String line;
	   while ((line = server.readLine())!= null)
	   {
		   outStream.println(line);
		   if (equal)
		   {   String line2 = in.readLine();
			   if (line2 == null) equal = false;
			   else if (line.compareTo(line2) != 0) equal = false;
		   }
	   };
	   server.close();
	   outStream.close();
	   if (in != null)
	   {  in.close();
	   }
	   if  (equal) { tempFile.delete(); println("No changes"); }
	   else { target.delete(); tempFile.renameTo(target); target.setLastModified(webtime); println("Updated!");}
  }catch (MalformedURLException ex){
	   println("Bad URL");
  }catch (UnknownHostException ex){
	   println("Unknown host");
  }catch (ConnectException ex){
	   println("Unable to connect");
  }catch (IOException ex){
	   println(ex.toString());
  }
 }
}