processorchainlist.java

最强的爬虫工程

/* ProcessorChainList
 *
 * $Id: ProcessorChainList.java,v 1.6 2006/08/04 04:02:39 gojomo Exp $
 *
 * Created on Mar 3, 2004
 *
 * Copyright (C) 2004 Internet Archive.
 *
 * This file is part of the Heritrix web crawler (crawler.archive.org).
 *
 * Heritrix is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Lesser Public License as published by
 * the Free Software Foundation; either version 2.1 of the License, or
 * any later version.
 *
 * Heritrix is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser Public License for more details.
 *
 * You should have received a copy of the GNU Lesser Public License
 * along with Heritrix; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */
package org.archive.crawler.framework;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;

import javax.management.AttributeNotFoundException;
import javax.management.MBeanException;
import javax.management.ReflectionException;

import org.archive.crawler.datamodel.CrawlOrder;
import org.archive.crawler.framework.exceptions.FatalConfigurationException;
import org.archive.crawler.settings.MapType;


/** A list of all the ProcessorChains.
 *
 * @author John Erik Halse
 */
public class ProcessorChainList {
    private List<ProcessorChain> chainList = new ArrayList<ProcessorChain>();
    private Map chainMap = new HashMap();

    /** Constructs a new ProcessorChainList.
     *
     * @param order the Crawl Order to get configuration from.
     *
     * @throws FatalConfigurationException is thrown if chains could not be
     *         set up properly.
     */
    public ProcessorChainList(CrawlOrder order)
            throws FatalConfigurationException {
        try {
            addProcessorMap(CrawlOrder.ATTR_PRE_FETCH_PROCESSORS,
                (MapType) order.
                    getAttribute(CrawlOrder.ATTR_PRE_FETCH_PROCESSORS));
            addProcessorMap(CrawlOrder.ATTR_FETCH_PROCESSORS, (MapType) order
                    .getAttribute(CrawlOrder.ATTR_FETCH_PROCESSORS));
            addProcessorMap(CrawlOrder.ATTR_EXTRACT_PROCESSORS, (MapType) order
                    .getAttribute(CrawlOrder.ATTR_EXTRACT_PROCESSORS));
            addProcessorMap(CrawlOrder.ATTR_WRITE_PROCESSORS, (MapType) order
                    .getAttribute(CrawlOrder.ATTR_WRITE_PROCESSORS));
            addProcessorMap(CrawlOrder.ATTR_POST_PROCESSORS, (MapType) order
                    .getAttribute(CrawlOrder.ATTR_POST_PROCESSORS));
        } catch (AttributeNotFoundException e) {
            throw new FatalConfigurationException("Could not get processors" +
                " from crawl order: " + e.getMessage());
        } catch (MBeanException e) {
            throw new FatalConfigurationException("Could not get processors" +
                " from crawl order: " + e.getMessage());
        } catch (ReflectionException e) {
            throw new FatalConfigurationException("Could not get processors" +
                " from crawl order: " + e.getMessage());
        }

        if (processorCount() == 0) { throw new FatalConfigurationException(
                "No processors defined"); }
    }

    /** Add a new chain of processors to the chain list.
     *
     * This method takes a map of processors and wraps it in a ProcessorChain
     * object and adds it to the list of chains.
     *
     * @param processorMap the processor map to be added.
     */
    public void addProcessorMap(String name, MapType processorMap) {
        ProcessorChain processorChain = new ProcessorChain(processorMap);
        ProcessorChain previousChain = getLastChain();
        if (previousChain != null) {
            previousChain.setNextChain(processorChain);
        }
        chainList.add(processorChain);
        chainMap.put(name, processorChain);
    }

    /** Get the first processor chain.
     *
     * @return the first processor chain.
     */
    public ProcessorChain getFirstChain() {
        return (ProcessorChain) chainList.get(0);
    }

    /** Get the last processor chain.
     *
     * The last processor chain should contain processors that should always
     * be run for a URI that has started its way through the processors.
     *
     * @return the last processor chain.
     */
    public ProcessorChain getLastChain() {
        if (size() == 0) {
            return null;
        } else {
            return (ProcessorChain) chainList.get(size() - 1);
        }
    }

    /** Get the total number of all processors in all the chains.
     *
     * @return the total number of all processors in all the chains.
     */
    public int processorCount() {
        int processorCount = 0;
        for (Iterator it = iterator(); it.hasNext();) {
            processorCount += ((ProcessorChain) it.next()).size();
        }
        return processorCount;
    }

    /** Get an iterator over the processor chains.
     *
     * @return an iterator over the processor chains.
     */
    public Iterator iterator() {
        return chainList.iterator();
    }

    /** Get the number of processor chains.
     *
     * @return the number of processor chains.
     */
    public int size() {
        return chainList.size();
    }

    /** Get a processor chain by its index in the list of chains.
     *
     * @param index the chains index in the list of chains.
     * @return the requested processor chain.
     */
    public ProcessorChain getProcessorChain(int index) {
        return (ProcessorChain) chainList.get(index);
    }

    /** Get a processor chain by its name.
     *
     * @param name name of the processor chain to get.
     * @return the requested processor chain.
     */
    public ProcessorChain getProcessorChain(String name) {
        return (ProcessorChain) chainMap.get(name);
    }

    public void kickUpdate() {
        for (ProcessorChain chain : chainList) {
            chain.kickUpdate();
        }
    }

}