report-week-3.md

This is my week 3 lab report

Part One - SearchEngine

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

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());
    }
}

class Handler implements URLHandler{

    ArrayList<String> strs = new ArrayList<>();

    public String handleRequest(URI url){

        if(url.getPath().equals("/")){
            return strs.toString();
        }

        if(url.getPath().contains("/add")){
            String[] inputStrs = url.getQuery().split("=");
            if (inputStrs[0].equals("s")){
                strs.add(inputStrs[1]);
                return inputStrs[1]; 
            }
        }

        if(url.getPath().contains("/search")){
            String[] inputStrs = url.getQuery().split("=");
            ArrayList<String> result = new ArrayList<>();
            String toSearch = inputStrs[1];
            for(String str: strs){
                if(str.toLowerCase().contains(toSearch.toLowerCase())){
                    result.add(str);
                    System.out.print(str);
                }
            }
            return result.toString();

        }
        return "404 not found";
    }
}

Here I am adding new strings to the original arraylist of strings, so I am calling /add.

strs is defautly an empty ArrayList.

When I type /add?=apple in the URL on the browser, I am calling the action in line 26 in the code.

/add?s=apple what is after ? is read as String[] inputStrs and will be splitted by =, so inputStrs[0] becomes s.

Line 28 becomes true, then strs added apple since it is inputStrs[1].

When I type /add?=pears in the URL on the browser, I am calling the action in line 26 in the code.

/add?s=pears what is after ? is read as String[] inputStrs and will be splitted by =, so inputStrs[0] becomes s.

Line 28 becomes true, then strs added pears since it is inputStrs[1].

When I type /add?=pineapple in the URL on the browser, I am calling the action in line 26 in the code.

/add?s=pineapple what is after ? is read as String[] inputStrs and will be splitted by =, so inputStrs[0] becomes s.

Line 28 becomes true, then strs added pineapple since it is inputStrs[1].

As a result, the array list is now {apples, pears, pineapple}.

Then, I am going to search for strings that have apple.

Here I am calling line 33 in my code by typing /search?s=apple, so that line 33 becomes true and continues the if statement.

What is after ? is read as String[] inputStrs and will be splitted by =, so inputStrs[0] becomes s.

Then inputStrs[1] becomes apple.

apple is passed to toSearch

str loops for apples, pears, pineapple in strs

and result stores the answer as {apples, pineapple}

Finally, we make it Strings to return.

Part Two - Debugging

In ArrayExample.java, I will be writing ReverseInPlace method. Failure-inducing method is:

The symptom is

The fixed code is

Problems in code: It fails to make the correct exchange and fails to loop through every index. So when it loops to index[1] which is 2, it fails to set the exchange.

In ListExample.java, I will be writing filter method. Failure inducing method is:

The symtom is

The fixed code is

It fails to do its work because if the index 0 is deleted, it will always add s to index 0.