package com.redfin.sitemapgenerator;

import java.net.MalformedURLException;
import java.net.URL;
import java.text.ParseException;
import java.util.Date;

/** Container for optional URL parameters */
//that weird thing with generics is so sub-classed objects will return themselves
//It makes sense, I swear!
 
http://madbean.com/2004/mb2004-3/
abstract class AbstractSitemapUrlOptions<U extends WebSitemapUrl, THIS extends AbstractSitemapUrlOptions<U,THIS>> {
	
Date lastMod;
	
ChangeFreq changeFreq;
	
Double priority;
	
URL url;
	
Class<U> clazz;
	

	
public AbstractSitemapUrlOptions(String url, Class<U> clazz) throws MalformedURLException {
		
this(new URL(url), clazz);
	
}
	

	
public AbstractSitemapUrlOptions(URL url, Class<U> clazz) {
		
if (url == null) throw new NullPointerException("URL may not be null");
		
this.url = url;
		
this.clazz = clazz;
	
}
	

	
/**
	 
* The date of last modification of the file. Note that this tag is
	 
* separate from the If-Modified-Since (304) header the server can
	 
* return, and search engines may use the information from both sources
	 
* differently.
	 
*/

	
public THIS lastMod(Date lastMod) {
		
this.lastMod = lastMod;
		
return getThis();
	
}
	

	
/**
	 
* The date of last modification of the file. Note that this tag is
	 
* separate from the If-Modified-Since (304) header the server can
	 
* return, and search engines may use the information from both sources
	 
* differently.
	 
* @throws ParseException if the string isn't a valid W3C date time
	 
* @see W3CDateFormat
	 
*/

	
public THIS lastMod(String lastMod) throws ParseException {
		
this.lastMod = new W3CDateFormat().parse(lastMod);
		
return getThis();
	
}
	

	
/**
	 
* How frequently the page is likely to change. This value provides
	 
* general information to search engines and may not correlate exactly
	 
* to how often they crawl the page. The value {@link ChangeFreq#ALWAYS} should be used to
	 
* describe documents that change each time they are accessed. The value
	 
* {@link ChangeFreq#NEVER} should be used to describe archived URLs.
	 
*
 

	 
* <p>Please note that the
	 
* value of this tag is considered a <em>hint</em> and not a command. Even though
	 
* search engine crawlers may consider this information when making
	 
* decisions, they may crawl pages marked {@link ChangeFreq#HOURLY} less frequently than
	 
* that, and they may crawl pages marked {@link ChangeFreq#YEARLY} more frequently than
	 
* that. Crawlers may periodically crawl pages marked {@link ChangeFreq#NEVER} so that
	 
* they can handle unexpected changes to those pages.</p>
	 
*/

	
public THIS changeFreq(ChangeFreq changeFreq) {
		
this.changeFreq = changeFreq;
		
return getThis();
	
}
	

	
/**
	 
* <p>The priority of this URL relative to other URLs on your site. Valid
	 
* values range from 0.0 to 1.0. This value does not affect how your
	 
* pages are compared to pages on other sites-it only lets the search
	 
* engines know which pages you deem most important for the crawlers.</p>
	 
*
 

	 
* <p>The default priority of a page is 0.5.</p>
	 
*
 

	 
* <p>Please note that the priority you assign to a page is not likely to
	 
* influence the position of your URLs in a search engine's result
	 
* pages. Search engines may use this information when selecting between
	 
* URLs on the same site, so you can use this tag to increase the
	 
* likelihood that your most important pages are present in a search
	 
* index.</p>
	 
*
 

	 
* <p>Also, please note that assigning a high priority to all of the URLs
	 
* on your site is not likely to help you. Since the priority is
	 
* relative, it is only used to select between URLs on your site.</p>
	 
*/

	
public THIS priority(Double priority) {
		
if (priority > 1.0) throw new IllegalArgumentException("Priority may not be greater than 1.0: " + priority);
		
if (priority < 0) throw new IllegalArgumentException("Priority may not be less than 0: " + priority);
		
this.priority = priority;
		
return getThis();
	
}
	

	
@SuppressWarnings("unchecked")
	
THIS getThis() {
		
return (THIS)this;
	
}
	

	
/** Return an URL based on these settings */
	
public U build() {
		
try {
			
return clazz.getConstructor(getClass()).newInstance(this);
		
} catch (Exception e) {
			
throw new RuntimeException(e);
		
}
	
}
	

}