cse15l-lab-reports

Week 3 Lab

My Search Engine (Part 1)

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Here is my code for my SearchEngine.java:

import java.io.IOException;
import java.net.URI;
import java.util.ArrayList;

class Handler implements URLHandler {
    // The one bit of state on the server: a number that will be manipulated by
    // various requests.
    int num = 0;
    ArrayList<String> items = new ArrayList<String>();
    ArrayList<String> elements = new ArrayList<String>();

    public String handleRequest(URI url) {
        if (url.getPath().equals("/")) {
            return String.format("Search for something or add it to the list!");
        } else if (url.getPath().contains("/search")) {
            String[] trySearch = url.getQuery().split("=");
            elements.clear();
            if (trySearch[0].equals("s")) {
                if (items.contains(trySearch[1])) {
                    for (String element : items){
                        if(element.contains(trySearch[1])) {
                            elements.add(element);
                        }
                    }
                    return String.format("Found These: '%s'", elements);
                }
                return String.format("searched: '%s'. Found no results, add it to the list.", trySearch[1]);
            }
            else {
                return String.format("Can't Search.");
            }

        } else {
            System.out.println("Path: " + url.getPath());
            if (url.getPath().contains("/add")) {
                String[] parameters = url.getQuery().split("=");
                if (parameters[0].equals("s")) {
                    items.add(parameters[1]);
                    return String.format("Added '%s'. Here are the items: %s", parameters[1], items);
                }
            }
            return "404 Not Found!";
        }
    }
}

class SearchEngine {
    public static void main(String[] args) throws IOException {
        if(args.length == 0){
            System.out.println("Missing port number! Try any number between 1024 to 49151");
            return;
        }

        int port = Integer.parseInt(args[0]);

        Server.start(port, new Handler());
    }
}

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Somehow it suddenley will print multiple of past add runs. I don’t know why, when I originally ran it a few days ago it worked fine. Also, when I run NumberServer.java I have the same problem but I haven’t changed anything about that program. This is my output after adding, “apple”, “app”, “cse15l”, and “broke”. I only added each of these strings once but I get this: For /add I am using the handleRequest method, and specifically the else statement at the end of it. The argument of handleRequest is the url of the page I am using, I think. The url changes, when I want to add something to the list. It changes before anything happens in code.

My Search works fine and gives me an output like this: For /search I am using the handleRequest method, and specifically the if and the else-if statements. The argument of handleRequest is the url of the page I am using. The url, changes when I want to search for something in the list. It changes before anything happens in code.

Here are screenshots of what the page looks like with the url in frame:

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Bugs (Part 2)

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The first bug I saw was in ArrayExamples.java. The test I ran to exploit this bug was:

@Test
  public void testReversed2() {
    int[] input1 = {1, 2, 3};
    assertArrayEquals(new int[]{3, 2, 1}, ArrayExamples.reversed(input1)); 
  }

The output I recieved from this test was, “arrays first differed at element [0]; expected:<1> but was:<0>”. The bug is arr[i] = newArray[arr.length - i - 1];, this will always put 0 into the array. To fix this, we write newArray[i] = arr[arr.length - i - 1. The test was expecting the arrays to be switched, but instead the bug will put 0 into the array instead because there is nothing in newArray.

The second bug I saw was in ListExamples.java. The test I ran to exploit this bug was:

@Test
    public void testMerge() {
        List<String> input1 = new ArrayList<>();
        List<String> input2 = new ArrayList<>();
        List<String> expected = new ArrayList<>();
        input1.add("a");
        input1.add("c");
        input2.add("b");
        input2.add("d");
        expected.add("a");
        expected.add("b");
        expected.add("c");
        expected.add("d");
       // ListExamples.merge(input1, input2);
        assertEquals(expected, ListExamples.merge(input1, input2));


    }

The output I recieved from this test was, “OutOfMemoryError: Java heap space”. The bug is index1 += 1 in the third while loop. The test was expecting a return of [a,b,c,d] but instead because of the incorrect while loop we will always enter an infinite loop before we return anything. It wouldn’t matter what you input, at the third while loop the program will always enter an infinite loop, unless after the first while loop index2 is already larger than list2. To fix this, we write index2 += 1; instead of index1 += 1; in the third while loop on line 43. This will allow index2 to update in the loop and it will no longer be an infinite loop.