notfilterwrapper.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/NotFilterWrapper.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 org.htmlparser.Node;
import org.htmlparser.NodeFilter;
import org.htmlparser.Parser;
import org.htmlparser.filters.NotFilter;
import org.htmlparser.parserapplications.filterbuilder.Filter;
import org.htmlparser.parserapplications.filterbuilder.SubFilterList;

/**
 * Wrapper for NotFilters.
 */
public class NotFilterWrapper
    extends
        Filter
{
    /**
     * The drop target container.
     */
    protected SubFilterList mContainer;
    
    /**
     * The underlying filter.
     */
    protected NotFilter mFilter;

    /**
     * Create a wrapper over a new NotFilter.
     */ 
    public NotFilterWrapper ()
    {
        mFilter = new NotFilter ();

        // add the subfilter container
        mContainer = new SubFilterList (this, "Predicate", 1);
        add (mContainer);
    }

    //
    // Filter overrides and concrete implementations
    //
    
    /**
     * Get the name of the filter.
     * @return A descriptive name for the filter.
     */
    public String getDescription ()
    {
        return ("Not");
    }

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

    /**
     * Get the underlying node filter object.
     * @return The node filter object suitable for serialization.
     */
    public NodeFilter getNodeFilter ()
    {
        NodeFilter predicate;
        NotFilter ret;
        
        ret = new NotFilter ();

        predicate = mFilter.getPredicate ();
        if (null != predicate)
            ret.setPredicate (((Filter)predicate).getNodeFilter ());
            
        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)
    {
        mFilter = (NotFilter)filter;
    }

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

        predicate = mFilter.getPredicate ();
        if (null != predicate)
            ret = new NodeFilter[] { predicate };
        else
            ret = new NodeFilter[0];

        return (ret);
    }

    /**
     * Assign the underlying node filter's subordinate filters.
     * @param filters The filters to insert into the underlying node filter.
     */
    public void setSubNodeFilters (NodeFilter[] filters)
    {
        if (0 != filters.length)
            mFilter.setPredicate (filters[0]);
        else
            mFilter.setPredicate (null);
    }

    /**
     * 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 name;
        String ret;

        if (null != mFilter.getPredicate ())
            name = ((Filter)mFilter.getPredicate ()).toJavaCode (out, context);
        else
            name = null;
        ret = "filter" + context[1]++;
        spaces (out, context[0]);
        out.append ("NotFilter ");
        out.append (ret);
        out.append (" = new NotFilter ();");
        newline (out);
        if (null != name)
        {
            spaces (out, context[0]);
            out.append (ret);
            out.append (".setPredicate (");
            out.append (name);
            out.append (");");
            newline (out);
        }
        
        return (ret);
    }

    //
    // 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));
    }
}