UrlComponents

package parsing;

import java.util.HashMap;
import java.util.Map;

public class UrlComponents {
  private static final String PROTOCOL_KEY = "protocol";
  private static final String DOMAIN_KEY = "domain";
  private static final String FILE_PATH_KEY = "path";
  private Map<String, String> components;
  
  public UrlComponents() {
    components = new HashMap<String, String>();
  }

  public void addProtocol(String protocol) {
    components.put(PROTOCOL_KEY, protocol.toLowerCase());
  }
  
  public String getProtocol() {
    return components.get(PROTOCOL_KEY);
  }

  public String getDomain() {
    return components.get(DOMAIN_KEY);
  }

  public void addDomain(String domain) {
    components.put(DOMAIN_KEY, domain);
  }
  
  public void addFilePath(String path) {
    components.put(FILE_PATH_KEY, path);
  }

  public String getFilePath() {
    return components.get(FILE_PATH_KEY);
  }
  
  

}

UrlParser

package parsing;

public class UrlParser {
  private static final int WIDTH_OF_COLON_AND_DOUBLE_SLASH = 3;
  private static final int STARTING_POSITION = 0;
  private static final String EMPTY = "";
  private StringBuffer url;
  private static final String SLASH = "/";
  private static final String COLON = ":";
  private UrlComponents components;

  public UrlComponents parse(String url) {
    this.url = new StringBuffer(url);
    components = new UrlComponents();

    parseProtocol();
    parseDomain();
    parseFilePath();

    return components;
  }

  private void parseFilePath() {
    String filePath = extractInstance(STARTING_POSITION, url.length());
    components.addFilePath(filePath);
  }

 private void parseProtocol() {
    components.addProtocol(extractInstance(0, COLON));
    url = removeProtocolAndPunctuation();
  }

  private void parseDomain() {
    String domain = extractInstance(STARTING_POSITION, SLASH);
    components.addDomain(domain);
    url = removeDomain(domain);
  }

  private StringBuffer removeDomain(String domain) {
    return url.replace(STARTING_POSITION, domain.length(), EMPTY);
  }

  private StringBuffer removeProtocolAndPunctuation() {
    return url.replace(STARTING_POSITION, positionOf(COLON) + WIDTH_OF_COLON_AND_DOUBLE_SLASH, EMPTY);
  }

  private String extractInstance(int startingIndex, int endingIndex) {
    return url.substring(startingIndex, endingIndex);
  }

  private String extractInstance(int startingIndex, String endingPattern) {
    return extractInstance(startingIndex, positionOf(endingPattern));
  }

  private int positionOf(String pattern) {
    return url.indexOf(pattern);
  }

}

UrlSplittingTest

package parsing;

import org.junit.Test;
import static org.junit.Assert.*;

public class UrlSplittingTest {
  
  /*
   *   TODO Test drive the simplest code you can (in the src folder) that parses URLs like these...
   
       http://sites.google.com/site/tddproblems/all-problems-1/URL-splitting
       http://en.wikipedia.org/wiki/Test-driven_development
       http://pragprog.com/magazines/2010-12/cohesive-software-design
       http://sites.google.com/site/tddproblems/all-problems-1/text-editor-end-of-line-trimming
       ftp://www.kumquat.com/sales/pricing
       ftp://user:password@server:port/path;type=typecode
        
        ...into their three main components: protocol, domain, path (and, in the case of some ftp urls, others)
        
        So, for "http://sites.google.com/site/tddproblems/all-problems-1/URL-splitting" :
        The protocol: "http"
        The domain name: "sites.google.com"
        The path: "/site/tddproblems/all-problems-1/URL-splitting"
        
   * 
   */ 
  
  @Test
  public void canExtract_http_Protocol() throws Exception {
    String url = "http://sites.google.com/site/tddproblems/all-problems-1/URL-splitting";
    UrlComponents components = new UrlParser().parse(url);
    
    assertEquals("http", components.getProtocol());
  }
  
  @Test
  public void canExtract_ftp_Protocol() throws Exception {
    String url = "ftp://www.kumquat.com/sales/pricing";
    UrlComponents components = new UrlParser().parse(url);
    
    assertEquals("ftp", components.getProtocol());
  }
  
  @Test
  public void canExtractDomain_ForHttp() throws Exception {
    String url = "http://sites.google.com/site/tddproblems/all-problems-1/URL-splitting";
    UrlComponents components = new UrlParser().parse(url);
    
    assertEquals("sites.google.com", components.getDomain());
  }
  
  @Test
  public void canExtractFilePathForHttp() throws Exception {
    String url = "http://sites.google.com/site/tddproblems/all-problems-1/URL-splitting";
    UrlComponents components = new UrlParser().parse(url);  
    
    assertEquals("/site/tddproblems/all-problems-1/URL-splitting", components.getFilePath());
  }
  

  //TODO: canExtractFilePath_ForHttp
  //TODO: canExtractDomain_ForFtp_WithNoAuthentication
  //TODO: canExtractServer_ForFtp
  //TODO: canExtractPort_ForFtp_WithServerAndPort


}