Graph Script Code

package ls.util;

import java.io.File;
import java.io.IOException;
import java.net.URL;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;

import javax.swing.ImageIcon;

import ls.util.msg.ErrorHandler;
import ls.util.msg.MessageHandler;
import ls.util.msg.MessageManager;

/**
 * A general utility class 
 * 
 * @author Lior Schejter
 */
public class Utils
{
	/**
	 * A message manager instance to handle various message managers
	 */
	private static MessageManager messageManager = new MessageManager();

	/**
	 * Add a message handler to the list of handlers used by this class's message manager
	 * 
	 * @param handler The handler to add
	 * @see #messageManager
	 * @see MessageManager
	 * @see MessageHandler
	 */
   public static void addMessageHandler(MessageHandler handler)
   {
	   if (handler == null) return;
	   messageManager.registerMessageHandler(handler);
   }
   /**
    * Add an error handler to this class's message manager
    * @param eh The error handler to add
    * @see #messageManager
    * @see MessageManager
    * @see ErrorHandler
    */
   public static void addErrorHandler(ErrorHandler eh)
   {
	   if (eh == null) return;
	   messageManager.registerErrorHandler(eh);
   }
   /* (non-Javadoc)
    * @see ls.util.msg.ErrorHandler#handleException(java.lang.Exception)
    */
   public static void exn(Exception exn)
   {
      messageManager.exn(exn);
   }
   /**
    * Output an error message. 
    * @param errMsg The error message to output.
    */
   public static void err(String errMsg)
   {
	   messageManager.err("Error: " + errMsg);
   }
   
   /* (non-Javadoc)
    * @see ls.util.msg.MessageHandler#handleMsg(java.lang.String)
    */
   public static void msg(String _msg)
   {
	   messageManager.msg(_msg);
   }
   public static final String EMPTY_STRING = "";
   
   /**
    * Return a new collection, with all the elements of the given iterator
    * @param iter
    * @return The new collection containing all elements of the given iterator
    */
   public static <E> Collection<E> collectionFromIterator(Iterator<E> iter)
   {
      Collection<E> ret = new ArrayList<E>();
      if (iter != null)
      {
         for (;iter.hasNext();)
         {
            ret.add(iter.next());
         }
      }
      return ret;
   }
   
   /**
    * Add the elments provided by the given iterator to the given collection
    * @param coll The target collection to add all the elements to
    * @param iter The source iterator
    */
   public static <E> void addToCollection(Collection<E> coll,Iterator<? extends E> iter)
   {
      if (coll == null || iter == null) return;
      for (; iter.hasNext();)
         coll.add(iter.next());
   }
   
   /**
    * Retrieve the given file's file extension
    * @param f The file to inspect
    * @return The file's extension or NULL if <code>f == null</code>.
    * @throws IOException In case the file cannot be inspected for some reason
    * @see File
    */
   public static String fileExtension(File f) throws IOException
   {
	   if (f == null) return null;
	   String filename = f.getCanonicalPath();
	   int lastDotInd = filename.lastIndexOf('.');
	   if (lastDotInd < 0) return "";
	   return filename.substring(lastDotInd+1);
   }
   
   /**
    * Create and return an icon based on the given class's resource path and the
    * path given
    * 
    * @param classObj The class object used to located the resource
    * @param path The path to the file
    * @return The new {@link ImageIcon ImageIcon} instance or null if no resource is found
    * @see Class#getResource(String)
    */
   public static ImageIcon getIcon(Class<?> classObj,String path)
   {
	   URL imgURL = classObj.getResource(path);
	   if (imgURL != null)
	   {
		   return new ImageIcon(imgURL);
	   }
	   else
	   {
		   Utils.err("Couldn't find file: " + path);
		   return null;
	   }
   }
}