// $Header: /home/cvs/jakarta-jmeter/src/htmlparser/org/htmlparser/beans/LinkBean.java,v 1.2 2004/02/10 13:41:09 woolfel Exp $
/*
 * ====================================================================
 * Copyright 2002-2004 The Apache Software Foundation.
 *
 * 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.
 * 
 */

// The developers of JMeter and Apache are greatful to the developers
// of HTMLParser for giving Apache Software Foundation a non-exclusive
// license. The performance benefits of HTMLParser are clear and the
// users of JMeter will benefit from the hard work the HTMLParser
// team. For detailed information about HTMLParser, the project is
// hosted on sourceforge at http://htmlparser.sourceforge.net/.
//
// HTMLParser was originally created by Somik Raha in 2000. Since then
// a healthy community of users has formed and helped refine the
// design so that it is able to tackle the difficult task of parsing
// dirty HTML. Derrick Oswald is the current lead developer and was kind
// enough to assist JMeter.

package org.htmlparser.beans;

import java.beans.PropertyChangeListener;
import java.beans.PropertyChangeSupport;
import java.io.Serializable;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;
import java.util.Vector;

import org.htmlparser.Node;
import org.htmlparser.Parser;
import org.htmlparser.tags.LinkTag;
import org.htmlparser.util.ParserException;
import org.htmlparser.visitors.ObjectFindingVisitor;

/**
 * Extract strings from a URL.
 * @author Derrick Oswald
 * Created on December 23, 2002, 5:01 PM
 */
public class LinkBean extends Object implements Serializable
{
    /**
     * Property name in event where the URL contents changes.
     */
    public static final String PROP_LINKS_PROPERTY = "Links";

    /**
     * Property name in event where the URL changes.
     */
    public static final String PROP_URL_PROPERTY = "URL";

    /**
     * Bound property support.
     */
    protected PropertyChangeSupport mPropertySupport;

    /**
     * The strings extracted from the URL.
     */
    protected URL[] mLinks;

    /**
     * The parser used to extract strings.
     */
    protected Parser mParser;

    /** Creates new StringBean */
    public LinkBean()
    {
        mPropertySupport = new PropertyChangeSupport(this);
        mLinks = null;
        mParser = new Parser();
    }

    //
    // internals
    //

    protected URL[] extractLinks(String url) throws ParserException
    {
        Parser parser;
        Vector vector;
        Node node;
        LinkTag link;
        URL[] ret;

        parser = new Parser(url);
        parser.registerScanners();
        ObjectFindingVisitor visitor = new ObjectFindingVisitor(LinkTag.class);
        parser.visitAllNodesWith(visitor);
        Node[] nodes = visitor.getTags();
        vector = new Vector();
        for (int i = 0; i < nodes.length; i++)
            try
            {
                link = (LinkTag) nodes[i];
                vector.add(new URL(link.getLink()));
            }
            catch (MalformedURLException murle)
            {
                //vector.remove (i);
                //i--;
            }
        ret = new URL[vector.size()];
        vector.copyInto(ret);

        return (ret);
    }

    /**
     * Determine if two arrays of URL's are the same.
     * @param array1 One array of URL's
     * @param array2 Another array of URL's
     * @return true if the URL's match in number and value,
     * false otherwise.
     */
    protected boolean equivalent(URL[] array1, URL[] array2)
    {
        boolean ret;

        ret = false;
        if ((null == array1) && (null == array2))
            ret = true;
        else if ((null != array1) && (null != array2))
            if (array1.length == array2.length)
            {
                ret = true;
                for (int i = 0; i < array1.length && ret; i++)
                    if (!(array1[i] == array2[i]))
                        ret = false;
            }

        return (ret);
    }

    //
    // Property change support.
    //

    /**
     * Add a PropertyChangeListener to the listener list.
     * The listener is registered for all properties.
     * @param listener The PropertyChangeListener to be added.
     */
    public void addPropertyChangeListener(PropertyChangeListener listener)
    {
        mPropertySupport.addPropertyChangeListener(listener);
    }

    /**
     * Remove a PropertyChangeListener from the listener list.
     * This removes a PropertyChangeListener that was registered for all properties.
     * @param the PropertyChangeListener to be removed.
     */
    public void removePropertyChangeListener(PropertyChangeListener listener)
    {
        mPropertySupport.removePropertyChangeListener(listener);
    }

    //
    // Properties
    //

    /**
     * Refetch the URL contents.
     */
    private void setLinks()
    {
        String url;
        URL[] urls;
        URL[] oldValue;

        url = getURL();
        if (null != url)
            try
            {
                urls = extractLinks(getURL());
                if (!equivalent(mLinks, urls))
                {
                    oldValue = mLinks;
                    mLinks = urls;
                    mPropertySupport.firePropertyChange(
                        PROP_LINKS_PROPERTY,
                        oldValue,
                        mLinks);
                }
            }
            catch (ParserException hpe)
            {
                mLinks = null;
            }
    }

    /**
     * Getter for property links.
     * @return Value of property links.
     */
    public URL[] getLinks()
    {
        if (null == mLinks)
            try
            {
                mLinks = extractLinks(getURL());
                mPropertySupport.firePropertyChange(
                    PROP_LINKS_PROPERTY,
                    null,
                    mLinks);
            }
            catch (ParserException hpe)
            {
                mLinks = null;
            }

        return (mLinks);
    }

    /**
     * Getter for property URL.
     * @return Value of property URL.
     */
    public String getURL()
    {
        return (mParser.getURL());
    }

    /**
     * Setter for property URL.
     * @param url New value of property URL.
     */
    public void setURL(String url)
    {
        String old;

        old = getURL();
        if (((null == old) && (null != url))
            || ((null != old) && !old.equals(url)))
        {
            try
            {
                mParser.setURL(url);
                mPropertySupport.firePropertyChange(
                    PROP_URL_PROPERTY,
                    old,
                    getURL());
                setLinks();
            }
            catch (ParserException hpe)
            {
                // failed... now what
            }
        }
    }

    /**
     * Getter for property Connection.
     * @return Value of property Connection.
     */
    public URLConnection getConnection()
    {
        return (mParser.getConnection());
    }

    /**
     * Setter for property Connection.
     * @param url New value of property Connection.
     */
    public void setConnection(URLConnection connection)
    {
        try
        {
            mParser.setConnection(connection);
            setLinks();
        }
        catch (ParserException hpe)
        {
            // failed... now what
        }
    }
}