/**
 *    '$RCSfile: GZipDataHandler.java,v $'
 *
 *     '$Author: costa $'
 *       '$Date: 2006-11-15 22:49:35 $'
 *   '$Revision: 1.10 $'
 *
 *  For Details: http://kepler.ecoinformatics.org
 *
 * Copyright (c) 2003 The Regents of the University of California.
 * All rights reserved.
 *
 * Permission is hereby granted, without written agreement and without
 * license or royalty fees, to use, copy, modify, and distribute this
 * software and its documentation for any purpose, provided that the
 * above copyright notice and the following two paragraphs appear in
 * all copies of this software.
 *
 * IN NO EVENT SHALL THE UNIVERSITY OF CALIFORNIA BE LIABLE TO ANY PARTY
 * FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
 * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
 * IF THE UNIVERSITY OF CALIFORNIA HAS BEEN ADVISED OF THE POSSIBILITY
 * OF SUCH DAMAGE.
 *
 * THE UNIVERSITY OF CALIFORNIA SPECIFICALLY DISCLAIMS ANY WARRANTIES,
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE
 * PROVIDED HEREUNDER IS ON AN "AS IS" BASIS, AND THE UNIVERSITY
 * OF CALIFORNIA HAS NO OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT,
 * UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
 */
package org.ecoinformatics.datamanager.download;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.zip.GZIPInputStream;

import org.ecoinformatics.datamanager.parser.Entity;


/**
 * This is a sub-class of CompressedDataHandler class. It will handle download
 * of GZipped data entity. After downloading, the compressed entity will be 
 * uncompressed and written to data storage interface transparently.
 * 
 * @author tao
 *
 */
public class GZipDataHandler extends CompressedDataHandler
{
  
   /**
    * Constructor
    * 
    * @param entity The entity object whose data is being downloaded. Used for
    *               quality reporting. Can be set to null in cases where we 
    *               don't need a back-pointer to the entity.
    * @param url  the url (or identifier) of Gzipped data entity
    * @param endPoint the object which provides ecogrid endpoint information
    */
    protected GZipDataHandler(Entity entity, String url, EcogridEndPointInterface endPoint)
    {
          super(entity, url, endPoint);
    }


    /**
     * Constructor
     * @param url  the url (or identifier) of Gzipped data entity
     * @param endPoint the object which provides ecogrid endpoint information
     */
     protected GZipDataHandler(String url, EcogridEndPointInterface endPoint)
     {
            super(url, endPoint);
     }

 
  /*
   * Class methods
   */
  
    /**
     * Gets the GZipDataHandler Object
     * 
     * @param entity The entity associated with the handler, possibly null
     * @param url The url (or identifier) of entity need be downloaded
     * @param endPoint  the EcogridEndPointInterface object
     * @return  GZipDataHandler object associated with the url
     */
     public static GZipDataHandler getGZipHandlerInstance(Entity entity,
                                                          String url, 
                                                          EcogridEndPointInterface endPoint) {
       GZipDataHandler  gzipHandler = (GZipDataHandler) getHandlerFromHash(url);
           
       if (gzipHandler == null) {        
         gzipHandler = new GZipDataHandler(entity, url, endPoint);
       }
           
       return gzipHandler;
     }
     
       
   /*
    * Overwrites the the method in DownloadHandler in order to uncompressed it.
    * It only writes the first file (if have mutiple) into DataStorageInterface
    */
   protected boolean writeRemoteInputStreamIntoDataStorage(InputStream in) 
           throws IOException
   {
	   boolean success = false;
	   GZIPInputStream gzipInputStream = null;
       
	   if (in == null)
	   {
		   return success;
	   }
       
	   try
	   {
		   gzipInputStream = new GZIPInputStream(in);
		   //this method will close the zipInpustream, and zipInpustream is not null!!!
		   success = super.writeRemoteInputStreamIntoDataStorage(gzipInputStream);			    
	   }
	   catch (IOException e)
	   {
	     String errorMsg = String.format("%s %s: %s", 
	                                     ONLINE_URLS_EXCEPTION_MESSAGE,
	                                     "Error downloading gzip file", 
	                                     e.getMessage()
	                                    );	     
       throw new IOException(errorMsg);
	   }
       
	   return success;
   }
   
   
   
   /*
    *  Gets data from Ecogrid server based on given Ecogrid endpoint
    *  and identifier. This method includes the uncompress process.
    *  It overwrites the one in DownloadHanlder.java
    */
   protected boolean getContentFromEcoGridSource(String endPoint, 
                                                 String ecogridIdentifier)
   {
	   boolean success = false;
       File gzipTmp = writeEcoGridCompressedDataIntoTmp(endPoint, 
                                                        ecogridIdentifier, 
                                                        ".gz");
       System.out.println("The gzip file name is "+gzipTmp);
       
       try
       {
	       if (gzipTmp != null)
	       {
	    	  InputStream stream = new FileInputStream(gzipTmp);
	    	  success = this.writeRemoteInputStreamIntoDataStorage(stream);
	       }
       }
       catch(Exception e)
       {
    	   System.out.println("Error is " + e.getMessage());
       }
       
       return success;
   }

}