AbstractCrawler.java :  » Web-Crawler » crawler » com » torunski » crawler » core » Java Open Source

/*
 * Copyright 2005, 2006 by Lars Torunski
 *
 * 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 com.torunski.crawler.core;

import java.util.Collection;

import javax.swing.event.EventListenerList;

import com.torunski.crawler.events.IParserEventListener;
import com.torunski.crawler.events.ParserEvent;
import com.torunski.crawler.filter.ILinkFilter;
import com.torunski.crawler.link.Link;
import com.torunski.crawler.model.ICrawlerModel;
import com.torunski.crawler.parser.IParser;
import com.torunski.crawler.parser.PageData;

/**
 * Implements the common needed crawler methods.
 * 
 * @author Lars Torunski
 * @version $Revision: 1.2 $
 */
public abstract class AbstractCrawler implements ICrawler {

  /** The loader and parser of the pages */
  protected IParser parser;
  
  /** The crawler model */
  protected ICrawlerModel model;
  
  /** The link filter for the links */
  protected ILinkFilter linkFilter;
  
  /** A list of all registered event listeners for this crawler */
  private EventListenerList listenerList = new EventListenerList();

  /**
   * @see com.torunski.crawler.core.ICrawler#getParser()
   */
  public IParser getParser() {
      return parser;
  }

  /**
   * @see com.torunski.crawler.core.ICrawler#setParser(com.torunski.crawler.parser.IParser)
   */
  public void setParser(IParser parser) {
      this.parser = parser;
  }

  /**
   * @see com.torunski.crawler.core.ICrawler#getModel()
   */
  public ICrawlerModel getModel() {
      return model;
  }

  /**
   * @see com.torunski.crawler.core.ICrawler#setModel(com.torunski.crawler.model.ICrawlerModel)
   */
  public void setModel(ICrawlerModel model) {
      this.model = model;
  }

  /**
   * @see com.torunski.crawler.core.ICrawler#getLinkFilter()
   */
  public ILinkFilter getLinkFilter() {
      return linkFilter;
  }

  /**
   * @see com.torunski.crawler.core.ICrawler#setLinkFilter(com.torunski.crawler.filter.ILinkFilter)
   */
  public void setLinkFilter(ILinkFilter linkFilter) {
      this.linkFilter = linkFilter;
  }

  /**
   * @see com.torunski.crawler.core.ICrawler#addParserListener(com.torunski.crawler.events.IParserEventListener)
   */
  public void addParserListener(IParserEventListener l) {
      listenerList.add(IParserEventListener.class, l);
  }

  /**
   * @see com.torunski.crawler.core.ICrawler#removeParserListener(com.torunski.crawler.events.IParserEventListener)
   */
  public void removeParserListener(IParserEventListener l) {
      listenerList.remove(IParserEventListener.class, l);
  }

  /**
   * Notify all listeners that have registered interest for
   * notification on this event type.
   * 
   * @param link the link of the PageData object.
   * @param pageData the PageData object to fire for.
   * @param newURIs the outgoing filtered links of the page.
   */
  protected void fireParserEvent(Link link, PageData pageData, Collection newURIs) {
      // create the event
      ParserEvent event = new ParserEvent(this, link, pageData, newURIs); 
  
      // Guaranteed to return a non-null array
      Object[] listeners = listenerList.getListenerList();
      
      // Process the listeners last to first, notifying
      // those that are interested in this event
      for (int i = listeners.length - 2; i >= 0; i -= 2) {
          if (listeners[i] == IParserEventListener.class) {
              ((IParserEventListener) listeners[i + 1]).parse(event);
          }
      }
  }

}