htmllinkprocessor.java

梦界家园程序开发基底框架

// HTMLParser Library v1.1 - A java-based parser for HTML
// Copyright (C) Dec 31, 2000 Somik Raha
//
// 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
//
// For any questions or suggestions, you can write to me at :
// Email :[e-mail]
// 
// Postal Address : 
// Somik Raha
// R&D Team
// Kizna Corporation
// Hiroo ON Bldg. 2F, 5-19-9 Hiroo,
// Shibuya-ku, Tokyo, 
// 150-0012, 
// JAPAN
// Tel  :  [phone]
// Fax : [phone]
// Website : www.kizna.com

package jm.util.html.util;
import java.util.Enumeration;
import java.util.Vector;
/**
 * Processor class for links, is present basically as a utility class.
 */
public class HTMLLinkProcessor {
/**
 * HTMLExtractor constructor comment.
 */
public HTMLLinkProcessor() {

}
/**
 * Parse a string and add all the directories found into a vector
 * @directories Directory vector
 * @temp String to be parsed
 */ 
@SuppressWarnings("unchecked")
public void addDirectoriesToVector(Vector directories, String temp) {
	int n;			
	do
	{
		n = temp.indexOf("/");
		if (n!=-1)
		{
			directories.addElement(temp.substring(0,n+1));
			temp=temp.substring(n+1,temp.length());
		}
	}
	while (n!=-1);
	// Check if remaining value of temp, has any .htm in it. If not, add it to the directories
	if (temp.length()>0)
	{
		int dotPos =  temp.toUpperCase().indexOf(".HTM");
		if (dotPos==-1)
		directories.addElement(temp+'/');
	}
}
/**
 * Check if a given link is relative, if yes, add the 
 * base url to it and return, else return unmodified.
 * @param link The link to be checked
 * @param url The base url
 * @return String Absolute URL
 */
public String checkIfLinkIsRelative(String link, String url) {
	if (link==null) return "";
	if (link.indexOf("http://")==-1 && link.indexOf("mailto:")==-1 && url != null)
	{
		String temp=url;
		Vector directories = new Vector();
		addDirectoriesToVector(directories, temp);
		link = handleRelationalPath(directories, link);
		String dir = createDirectory(directories);
		link = removeFirstSlashIfFound(link);
		link=dir+link;		
	}
	return link;
}
/** 
 * Create the directory by summing all the contents
 * of the directory vector
 * @param directories
 * @return String The Directory string
 */
public String createDirectory(Vector directories) {
	String dir="";			
	for (Enumeration e = directories.elements();e.hasMoreElements();)
	{
		dir += (String)e.nextElement();
	}
	return dir;
}

public String extract(String link,String url) {
		link = checkIfLinkIsRelative(link, url);
		
		
		// Check if there are any escape characters to be filtered out (we are
		// currently removing #38;
		link=removeEscapeCharacters(link);
		return link;
}
public String handleRelationalPath(Vector directories, String link) {
	int dotLoc = link.indexOf("..");
	while (dotLoc==0)
	{
		link = link.substring(3,link.length());
		if (directories.size()>1)
		directories.removeElementAt(directories.size()-1);
		dotLoc=link.indexOf("..");
	}
	return link;
}
	public static String removeEscapeCharacters(String link)
	{
		int state = 0;
		String temp = "",retVal="";
		for (int i=0;i<link.length();i++)
		{
			char ch = link.charAt(i);
			if (state==4) 
			{
				state=0;
			}
			if (ch=='#' && state==0) 
			{
				state=1;
				continue;
			}
			if (state==1)
			{
				if (ch=='3')
				{
					state=2; 
					continue;
				}
				else
				{
					state=0;
					retVal+=temp;
				}
			}		
			if (state==2)
			{
				if (ch=='8')
				{
				 	state=3;
					continue;
				}
				else
				{
					state=0;
					retVal+=temp;
				}
			}	
			if (state==3)
			{
				if (ch==';')
				{
					state=4;
					continue;
				}
				else
				{
					state=0;
					retVal+=temp;
				}
			}				
			if (state==0) retVal+=ch; else temp+=ch;
		}
		return retVal;
	}
public String removeFirstSlashIfFound(String link) {
	if (link==null || link.length()==0) return null;
	if (link.charAt(0)=='/')
	link=link.substring(1,link.length());
	return link;
}
}