/*
    * Copyright 2000-2004 The Apache Software Foundation.
    * 
    * Licensed under the Apache License, Version 2.0 (the "License");
    * you may not use this file except in compliance with the License.
    * You may obtain a copy of the License at
    * 
    *      http://www.apache.org/licenses/LICENSE-2.0
    * 
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package org.apache.jetspeed.services.transformer;
  
  // turbine stuff
  import java.io.Reader;
  
  import javax.servlet.ServletConfig;
  
  import org.apache.jetspeed.util.rewriter.ClipperRewriter;
  import org.apache.turbine.services.TurbineBaseService;
  import org.apache.turbine.util.Log;
  
  /***
   * Simple implementation of the TransformerService.
   * @author <a href="mailto:mmari@ce.unipr.it">Marco Mari</a>
   * @version $Id: JetspeedTransformerService.java,v 1.2 2004/02/23 03:39:10 jford Exp $* 
   */
  public class JetspeedTransformerService
  	extends TurbineBaseService
  	implements TransformerService
  {
  	protected ClipperRewriter rewriter = null;
  	String convertedString;
  
  	/***
  	 * This is the early initialization method called by the 
  	 * Turbine <code>Service</code> framework
  	 * @param conf The <code>ServletConfig</code>
  	 */
  	public void init(ServletConfig conf)
  	{
  		// controls if already initialized
  		if (getInit())
  		{
  			return;
  		}
  
  		rewriter = new ClipperRewriter();
  		setInit(true);
  	}
  
  	/***
  	 * Late init. Don't return control until early init says we're done.
  	 */
  	public void init()
  	{
  		while (!getInit())
  		{
  			try
  			{
  				Thread.sleep(500);
  				Log.info("JetspeedTransformerService: Waiting for init()...");
  			}
  			catch (InterruptedException ie)
  			{
  				Log.error(ie);
  			}
  		}
  	}
  
  	/***
  	 * Finds an element in a web page
  	 * 
  	 * @param htmlReader Reader for the html rewriter
  	 * @param url        page address
  	 * @param element    a part of the element to search
  	 */
  	public String findElement(Reader htmlReader, String url, String element)
  	{
  		// If not indicated, assume to find the first element
  		return clipElementsNumber(htmlReader, url, element, null, 1);
  	}
  
  	/***
  	 * Clips the part of a web page between startElement and stopElement
  	 * 
  	 * @param htmlReader    Reader for the html rewriter
  	 * @param url           page address
  	 * @param startElement  the first element to clip
  	 * @param lastElement   the last element to clip
  	 */
  	public String clipElements(
  		Reader htmlReader,
  		String url,
 		String startElement,
 		String stopElement)
 	{
 		// If not indicated, assume to find the first startElement
 		return clipElementsNumber(
 			htmlReader,
 			url,
 			startElement,
 			stopElement,
 			1);
 	}
 
 	/***
 	 * Finds in an HTML page the "tagNumber" tag of type "element"
 	 * Example: element = "p", tagNumber = "3"
 	 * Page content:
 	 * <p>..</p>
 	 * <p>..</p>
 	 * <p>..   <---Finds this    
 	 * 
 	 * @param htmlReader Reader for the html rewriter
 	 * @param url        page address
 	 * @param element    the element to search
 	 * @param tagNumber  the number of the element to search
 	 */
 	public String findElementNumber(
 		Reader htmlReader,
 		String url,
 		String element,
 		int tagNumber)
 	{
 		return clipElementsNumber(htmlReader, url, element, null, tagNumber);
 	}
 
 	/***
 	 * Clips a part of a web page, starting from the "tagNumber" "startElement"
 	 * Example: startElement = "p", tagNumber = "3", stopElement = "img"
 	 * Page content:
 	 * <p>..</p>
 	 * <p>..</p>
 	 * <p>..   <---Starts here
 	 * ........<img>  <---Stops here
 	 * 
 	 * @param htmlReader    Reader for the html rewriter
 	 * @param url           page address
 	 * @param startElement  the first element to clip
 	 * @param stopElement   the last element to clip
 	 * @param tagNumber     the number of the first element to clip
 	 */
 	public String clipElementsNumber(
 		Reader htmlReader,
 		String url,
 		String startElement,
 		String stopElement,
 		int tagNumber)
 	{
 		rewriter.setStartElement(startElement);
 		rewriter.setStopElement(stopElement);
 		rewriter.setStartElementNumber(tagNumber);
 
 		try
 		{
 			convertedString = rewriter.rewrite(htmlReader, url);
 		}
 		catch (Exception e)
 		{
 			Log.info("Exception occurred:" + e.toString());
 			e.printStackTrace();
 		}
 
 		return convertedString;
 	}
 
 }