Ashby Coding Challenge

CbcRssParser.java

/**
 * 
 */
package com.miovision.rss.reader;

import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.text.DateFormat;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.Date;
import java.util.List;
import java.util.Locale;

/**
 * @author David Ashby
 * for Miovision
 *
 */
public class CbcRssParser {

	private static final String TITLE_START_TAG = "<title>";
	private static final String TITLE_END_TAG = "</title>";
	private static final String ITEM_START_TAG = "<item";
	private static final String ITEM_END_TAG = "</item>";
	private static final String CBC_URL = "http://rss.cbc.ca/lineup/topstories.xml";
	private static final String LINK_START_TAG = "<link>";
	private static final String LINK_END_TAG = "</link>";
	private static final String DATE_START_TAG = "<pubDate>";
	private static final String DATE_END_TAG = "</pubDate>";
	private static final int NUMBER_OF_STORIES = 5;

	private List<RssStory> getStories() {
		
		//-variables defined before they are needed 
        String body = getBody(CBC_URL);
		
		return parseBodyToStories(body);
	}
	
	static class StoryComparer implements Comparator<RssStory> {
        public int compare(RssStory x, RssStory y)
        {
            if (x == y)
                return 0;
            else
                return y.getDate().compareTo(x.getDate());
        }
    }
	
	private List<RssStory> parseBodyToStories(String body) {
        
		List<RssStory> result = new ArrayList<RssStory>();
		int start = 0;
        while (true)
        {
        	//-"<item" should be a constant
            int nextItemStart = body.indexOf(ITEM_START_TAG, start);
            int nextItemEnd = body.indexOf(ITEM_END_TAG, nextItemStart);
            if (nextItemStart < 0 || nextItemEnd < 0) break;

            String nextItem = body.substring(nextItemStart, nextItemEnd);
            String title = extractString(nextItem, TITLE_START_TAG, TITLE_END_TAG);
            String link = extractString(nextItem, LINK_START_TAG, LINK_END_TAG); 
            DateFormat format = new SimpleDateFormat("EEE, dd MMM yyyy HH:MM:SS zzz", Locale.ENGLISH);
            String dateString = extractString(nextItem, DATE_START_TAG, DATE_END_TAG);
			Date date = null;
            try {
				date = format.parse(dateString);
			} catch (ParseException e) {
				System.out.println("Failed to parse date " + dateString);
			}
            

            result.add(new RssStory(title, link, date));

            start = nextItemEnd;
        }
        return result;
	}

	private String extractString(String nextItem, String startTag, String endTag) {
		return nextItem.substring(nextItem.indexOf(startTag)+startTag.length(), nextItem.indexOf(endTag));
	}

	private String getBody(String url) {
		String result = "";
		try {
            URL urlUrl = new URL(url);
            HttpURLConnection conn = (HttpURLConnection) urlUrl.openConnection();
            conn.setRequestMethod("GET");
            BufferedReader rd = new BufferedReader(new InputStreamReader(conn.getInputStream()));
            String line;
            while ((line = rd.readLine()) != null) {
                result += line;
            }
        }
		catch( FileNotFoundException fnfe)
		{
			System.out.println("Unable to access page" + url);
		}
        catch (Exception e) {
        	//
            throw new RuntimeException(e);
        }
		return result;
	}

	private void printNStories(List<RssStory> stories, int n) {
		int index = 0;
		for (RssStory story : stories) {
			if (index == n)
				break;
			// For debugging
			// System.out.println(story.getTitle() + " " + story.getDate());
			System.out.println(story.getTitle());
			index++;
		}
	}
	
	private void printSortedStories(int numberOfStories) {
		List<RssStory> listOfStories = getStories();
		printNStories(sortList(listOfStories, new StoryComparer()),numberOfStories);
	}

	private <T> List<T> sortList(List<T> listOfStories, Comparator<T> comparator) {
		Collections.sort(listOfStories, comparator);
		return listOfStories;
	}

	public static void main(String[] args) {
		CbcRssParser parser = new CbcRssParser();
		parser.printSortedStories(NUMBER_OF_STORIES);
	}
}

RssStory.java

package com.miovision.rss.reader;

import java.util.Date;

public class RssStory {
	private String title;
	private String link;
	private Date date;
	
	public RssStory(String title, String link, Date date) {
		this.title = title;
		this.link = link;
		this.date = date;
	}
	/* (non-Javadoc)
	 * @see java.lang.Object#hashCode()
	 */
	@Override
	public int hashCode() {
		// TODO Auto-generated method stub
		return super.hashCode();
	}
	/* (non-Javadoc)
	 * @see java.lang.Object#equals(java.lang.Object)
	 */
	@Override
	public boolean equals(Object obj) {
		// if not an instance of rssStory
		if(!(obj instanceof RssStory))
		{
			return false;
		}
		RssStory story = (RssStory)obj;
		// if title is  not equal
		return this.title.equals(story.getTitle());
	}
	public String getTitle() {
		return title;
	}
	public void setTitle(String title) {
		this.title = title;
	}
	public String getLink() {
		return link;
	}
	public void setLink(String link) {
		this.link = link;
	}
	public Date getDate() {
		return date;
	}
	public void setDate(Date date) {
		this.date = date;
	}
}