tagnamefilterwrapper.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 Derrick Oswald
//
// Revision Control Information
//
// $Source: /cvsroot/htmlparser/htmlparser/src/org/htmlparser/parserapplications/filterbuilder/wrappers/TagNameFilterWrapper.java,v $
// $Author: derrickoswald $
// $Date: 2005/04/12 11:27:42 $
// $Revision: 1.2 $
//
// 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.parserapplications.filterbuilder.wrappers;

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Set;

import javax.swing.JComboBox;

import org.htmlparser.Node;
import org.htmlparser.NodeFilter;
import org.htmlparser.Parser;
import org.htmlparser.Tag;
import org.htmlparser.filters.TagNameFilter;
import org.htmlparser.parserapplications.filterbuilder.Filter;
import org.htmlparser.tags.CompositeTag;
import org.htmlparser.util.NodeIterator;
import org.htmlparser.util.NodeList;
import org.htmlparser.util.ParserException;

/**
 * Wrapper for TagNameFilters.
 */
public class TagNameFilterWrapper
    extends
        Filter
    implements
        ActionListener
{
    /**
     * The underlying filter.
     */
    protected TagNameFilter mFilter;

    /**
     * Combo box for tag name.
     */
    protected JComboBox mName;

    /**
     * Create a wrapper over a new TagNameFilter.
     */ 
    public TagNameFilterWrapper ()
    {
        mFilter = new TagNameFilter ();

        // add the tag name choice
        mName = new JComboBox ();
        mName.setEditable (true);
        add (mName);
        mName.addItem (mFilter.getName ());
        mName.addActionListener (this);
    }

    //
    // Filter overrides and concrete implementations
    //

    /**
     * Get the name of the filter.
     * @return A descriptive name for the filter.
     */
    public String getDescription ()
    {
        return ("Tag named");
    }

    /**
     * Get the resource name for the icon.
     * @return The icon resource specification.
     */
    public String getIconSpec ()
    {
        return ("images/TagNameFilter.gif");
    }

    /**
     * Get the underlying node filter object.
     * @return The node filter object suitable for serialization.
     */
    public NodeFilter getNodeFilter ()
    {
        TagNameFilter ret;
        
        ret = new TagNameFilter ();
        ret.setName (mFilter.getName ());
            
        return (ret);
    }

    /**
     * Assign the underlying node filter for this wrapper.
     * @param filter The filter to wrap.
     * @param context The parser to use for conditioning this filter.
     * Some filters need contextual information to provide to the user,
     * i.e. for tag names or attribute names or values,
     * so the Parser context is provided. 
     */
    public void setNodeFilter (NodeFilter filter, Parser context)
    {
        Set set;

        mFilter = (TagNameFilter)filter;
        set = new HashSet ();
        context.reset ();
        try
        {
            for (NodeIterator iterator = context.elements (); iterator.hasMoreNodes (); )
                addName (set, iterator.nextNode ());
        }
        catch (ParserException pe)
        {
            // oh well, we tried
        }
        for (Iterator iterator = set.iterator (); iterator.hasNext (); )
            mName.addItem (iterator.next ());
        mName.setSelectedItem (mFilter.getName ());
    }

    /**
     * Get the underlying node filter's subordinate filters.
     * @return The node filter object's contained filters.
     */
    public NodeFilter[] getSubNodeFilters ()
    {
        return (new NodeFilter[0]);
    }

    /**
     * Assign the underlying node filter's subordinate filters.
     * @param filters The filters to insert into the underlying node filter.
     */
    public void setSubNodeFilters (NodeFilter[] filters)
    {
        // should we complain?
    }

    /**
     * Convert this filter into Java code.
     * Output whatever text necessary and return the variable name.
     * @param out The output buffer.
     * @param context Three integers as follows:
     * <li>indent level - the number of spaces to insert at the beginning of each line</li>
     * <li>filter number - the next available filter number</li>
     * <li>filter array number - the next available array of filters number</li>
     * @return The variable name to use when referencing this filter (usually "filter" + context[1]++) 
     */
    public String toJavaCode (StringBuffer out, int[] context)
    {
        String ret;
        
        ret = "filter" + context[1]++;
        spaces (out, context[0]);
        out.append ("TagNameFilter ");
        out.append (ret);
        out.append (" = new TagNameFilter ();");
        newline (out);
        spaces (out, context[0]);
        out.append (ret);
        out.append (".setName (\"");
        out.append (mFilter.getName ());
        out.append ("\");");
        newline (out);
        
        return (ret);
    }

    /**
     * Add the tag name and it's children's tag names to the set of tag names.
     * @param set The set to add to.
     * @param node The node to get the names from.
     */
    protected void addName (Set set, Node node)
    {
        NodeList children;

        if (node instanceof Tag)
        {
            set.add (((Tag)node).getTagName ());
            if (node instanceof CompositeTag)
            {
                children = ((CompositeTag)node).getChildren ();
                if (null != children)
                    for (int i = 0; i < children.size (); i++)
                        addName (set, children.elementAt (i));
            }
        }
    }
    //
    // NodeFilter interface
    //

    /**
     * Predicate to determine whether or not to keep the given node.
     * The behaviour based on this outcome is determined by the context
     * in which it is called. It may lead to the node being added to a list
     * or printed out. See the calling routine for details.
     * @return <code>true</code> if the node is to be kept, <code>false</code>
     * if it is to be discarded.
     * @param node The node to test.
     */
    public boolean accept (Node node)
    {
        return (mFilter.accept (node));
    }

    //
    // ActionListener interface
    //

    /**
     * Invoked when an action occurs on the combo box.
     * @param event Details about the action event.
     */
    public void actionPerformed (ActionEvent event)
    {
        Object source;
        Object[] selection;

        source = event.getSource ();
        if (source == mName)
        {
            selection = mName.getSelectedObjects ();
            if ((null != selection) && (0 != selection.length))
                mFilter.setName ((String)selection[0]);
        }
    }
}