linkregexfilter.java

本程序用于对页面信息进行提取并分析

// HTMLParser Library $Name: v1_6_20060319 $ - A java-based parser for HTML
// http://sourceforge.org/projects/htmlparser
// Copyright (C) 2005 John Derrick
//
// Revision Control Information
//
// $Source: /cvsroot/htmlparser/htmlparser/src/org/htmlparser/filters/LinkRegexFilter.java,v $
// $Author: derrickoswald $
// $Date: 2005/09/18 23:40:44 $
// $Revision: 1.4 $
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
//
// This library 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 General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
//

package org.htmlparser.filters;

import java.util.regex.Matcher;
import java.util.regex.Pattern;

import org.htmlparser.Node;
import org.htmlparser.NodeFilter;
import org.htmlparser.tags.LinkTag;

/**
 * This class accepts tags of class LinkTag that contain a link matching a given
 * regex pattern. Use this filter to extract LinkTag nodes with URLs that match
 * the desired regex pattern.
 */
public class LinkRegexFilter implements NodeFilter
{
    /**
     * The regular expression to use on the link.
     */
    protected Pattern mRegex;

    /**
     * Creates a LinkRegexFilter that accepts LinkTag nodes containing
     * a URL that matches the supplied regex pattern.
     * The match is case insensitive.
     * @param regexPattern The pattern to match.
     */
    public LinkRegexFilter (String regexPattern)
    {
        this (regexPattern, true);
    }

    /**
     * Creates a LinkRegexFilter that accepts LinkTag nodes containing
     * a URL that matches the supplied regex pattern.
     * @param regexPattern The regex pattern to match.
     * @param caseSensitive Specifies case sensitivity for the matching process.
     */
    public LinkRegexFilter (String regexPattern, boolean caseSensitive)
    {
        if (caseSensitive)
            mRegex = Pattern.compile (regexPattern);
        else
            mRegex = Pattern.compile (regexPattern,
                Pattern.CASE_INSENSITIVE | Pattern.UNICODE_CASE);
    }

    /**
     * Accept nodes that are a LinkTag and have a URL
     * that matches the regex pattern supplied in the constructor.
     * @param node The node to check.
     * @return <code>true</code> if the node is a link with the pattern.
     */
    public boolean accept (Node node)
    {
        boolean ret;

        ret = false;
        if (LinkTag.class.isAssignableFrom (node.getClass ()))
        {
            String link = ((LinkTag)node).getLink ();
            Matcher matcher = mRegex.matcher (link);
            ret = matcher.find ();
        }

        return (ret);
    }
}