HW is done

org/geekhub/ConnectionUtils.java

@@ -1,22 +1,39 @@
 package org.geekhub;
 
+import java.io.BufferedInputStream;
+import java.io.ByteArrayOutputStream;
 import java.io.IOException;
+import java.io.InputStream;
 import java.net.URL;
 
 /**
  * Utils class that contains useful method to interact with URLConnection
  */
 public class ConnectionUtils {
 
+    public static final int BUFFER_SIZE = 16 * 1024;
+
     /**
      * Downloads content for specified URL and returns it as a byte array.
      * Should be used for small files only. Don't use it to download big files it's dangerous.
+     *
      * @param url
      * @return
      * @throws IOException
      */
     public static byte[] getData(URL url) throws IOException {
-        //implement me
-        return null;
+
+        ByteArrayOutputStream outputStream = new ByteArrayOutputStream(BUFFER_SIZE);
+
+        try (InputStream is = new BufferedInputStream(url.openConnection().getInputStream(), BUFFER_SIZE)) {
+            int currentByte;
+            while ((currentByte = is.read()) != -1) {
+                outputStream.write(currentByte);
+            }
+        }
+
+        return outputStream.toByteArray();
+
     }
+
 }

org/geekhub/ImageCrawler.java

@@ -1,10 +1,11 @@
 package org.geekhub;
 
-import java.io.*;
+import java.io.IOException;
 import java.net.MalformedURLException;
 import java.net.URL;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
+import java.util.regex.Pattern;
 
 /**
  * ImageCrawler downloads all images to specified folder from specified resource.
@@ -15,7 +16,7 @@ public class ImageCrawler {
 
     //number of threads to download images simultaneously
     public static final int NUMBER_OF_THREADS = 10;
-
+    Pattern imagePattern = Pattern.compile(".+\\.(jpg|jpeg|png|bmp|tiff)");
     private ExecutorService executorService = Executors.newFixedThreadPool(NUMBER_OF_THREADS);
     private String folder;
 
@@ -25,11 +26,19 @@ public ImageCrawler(String folder) throws MalformedURLException {
 
     /**
      * Call this method to start download images from specified URL.
+     *
      * @param urlToPage
      * @throws IOException
      */
     public void downloadImages(String urlToPage) throws IOException {
-        //implement me
+        URL url = new URL(urlToPage);
+        if (isImageURL(url)) {
+            executorService.submit(new ImageTask(url, folder));
+        } else {
+            Page page = new Page(url);
+            page.getImageLinks().stream().forEach(link -> executorService.submit(new ImageTask(link, folder)));
+        }
+
     }
 
     /**
@@ -41,10 +50,7 @@ public void stop() {
 
     //detects is current url is an image. Checking for popular extensions should be enough
     private boolean isImageURL(URL url) {
-        //implement me
-        return false;
+        return imagePattern.matcher(url.toString()).matches();
     }
 
-
-
 }

org/geekhub/ImageTask.java

@@ -1,6 +1,11 @@
 package org.geekhub;
 
+import java.io.IOException;
 import java.net.URL;
+import java.nio.file.Files;
+import java.nio.file.InvalidPathException;
+import java.nio.file.Path;
+import java.nio.file.Paths;
 
 /**
  * Represents worker that downloads image from URL to specified folder.<br/>
@@ -20,7 +25,12 @@ public ImageTask(URL url, String folder) {
      */
     @Override
     public void run() {
-       //implement me
+        try {
+            Path path = Paths.get(folder, buildFileName(url));
+            Files.write(path, ConnectionUtils.getData(url));
+        } catch (IOException | InvalidPathException e) {
+            e.printStackTrace();
+        }
     }
 
     //converts URL to unique file name

org/geekhub/Main.java

@@ -15,7 +15,7 @@ public static void main(String[] args) throws IOException {
 
         Scanner scanner = new Scanner(System.in);
         String command;
-        while(!"exit".equals(command = scanner.next())) {
+        while (!"exit".equals(command = scanner.next())) {
             imageCrawler.downloadImages(command);
             System.out.println("...and another url:");
         }

org/geekhub/Page.java

@@ -3,7 +3,9 @@
 import java.io.IOException;
 import java.net.MalformedURLException;
 import java.net.URL;
-import java.util.*;
+import java.util.Collection;
+import java.util.HashSet;
+import java.util.Set;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
@@ -20,6 +22,7 @@ public class Page {
 
     /**
      * Be careful, constructor downloads content, it could be slow.
+     *
      * @param url
      * @throws IOException
      */
@@ -30,6 +33,7 @@ public Page(URL url) throws IOException {
 
     /**
      * Extracts all links from the page like <a href={link}>bla</a>. Method does not cache content. Each time new list will be returned.
+     *
      * @return list of URLs from that page.
      * @throws MalformedURLException
      */
@@ -39,6 +43,7 @@ public Collection<URL> getLinks() throws MalformedURLException {
 
     /**
      * Extracts all links to images from the page like <img src={link}/>. Method does not cache content. Each time new list will be returned.
+     *
      * @return list of URLs to images from that page.
      * @throws MalformedURLException
      */
@@ -48,7 +53,7 @@ public Collection<URL> getImageLinks() throws MalformedURLException {
 
     private Collection<URL> extractMatches(Matcher matcher) throws MalformedURLException {
         Set<URL> links = new HashSet<>();
-        while(matcher.find()) {
+        while (matcher.find()) {
             links.add(new URL(url, matcher.group(1)));
         }
         return links;