I'm loosing my mind here...

Question about the task

Under discussion

Hello everyone! For the last couple of days, I have been trying to solve this task... I know I'm really close, but I can't figure this out: Why is this code not capturing name as a next token?! Any hint? EDITED: Test passed, but when try to pass the task...oh wonder, no pass... NEW CODE:

Scanner scan = new Scanner(System.in);
        String url = scan.nextLine();
//        String url = "http://codegym.cc/alpha/index.html?lvl=15&view&name=Amigo";
        String subStr = url.substring(url.indexOf("?") + 1);

        Pattern p = Pattern.compile("(\\w+)");
        Pattern doublPatt = Pattern.compile("([0-9]+\\.[0-9]+)");
        Matcher doublMatch = doublPatt.matcher(subStr);

        Matcher m = p.matcher(subStr);
        double d = 0;
        String validToken = "";
        String doubleToken = "";
        List<Object> obj = new ArrayList<Object>();
        while(m.find()){
            validToken = m.group();
            if(doublMatch.find()){
                try{
                    doubleToken = doublMatch.group(1);
                    d = Double.parseDouble(doubleToken);
                    if(!((d % 1) == 0)){
                        obj.add(d);
                    }
                }catch(Exception e){

                }
            }
            char ch = validToken.toCharArray()[0];
            if(Character.isLowerCase(ch)) obj.add(validToken);
        }
        for(Object o : obj){
            if(!(o instanceof Double)) System.out.print(o + " ");
        }
        for(Object o : obj){
            if(o instanceof Double) {
                System.out.println();
                alert(d);
            }
        }

Read a URL from the console.
Display a space-delimited list of all the parameters (The parameters follow the "?" and are separated by "&", e.g. "lvl=15").
The URL contains at least 1 parameter.
The parameters must be displayed in the same order in which they are present in the URL.
If the obj parameter is present, pass its value to the relevant alert method.
alert(double value) - for numbers (fractional numbers have a decimal point)
alert(String value) - for strings
Note that the alert method must be called AFTER the list of all parameters is displayed.

Example 1

Input:
http://codegym.cc/alpha/index.html?lvl=15&view&name=Amigo

Output:
lvl view name

Example 2

Input:
http://codegym.cc/alpha/index.html?obj=3.14&name=Amigo

Output:
obj name double: 3.14

Requirements:

The program should read only one line from the keyboard.
The Solution class must not have static fields.
The program must display data on the screen in accordance with the task conditions.
The program should call the alert method with the double parameter if the obj parameter can be correctly converted to a double.
The program should call the alert method with the String parameter if the obj parameter CANNOT be correctly converted to a double.

package com.codegym.task.task15.task1527; /* Request parser */ import java.util.*; public class Solution { public static void main(String[] args) { //write your code here Scanner scan = new Scanner(System.in); // String url = scan.nextLine(); String url = "http://codegym.cc/alpha/index.html?lvl=15&view&name=Amigo"; String subStr = url.substring(url.indexOf("?") + 1); System.out.println(subStr); StringTokenizer strToken = new StringTokenizer(subStr, "&="); double d = 0; String validToken = ""; List<Object> obj = new ArrayList<Object>(); while(strToken.hasMoreTokens()){ validToken = strToken.nextToken(); System.out.println(validToken); char ch = validToken.toCharArray()[0]; if(Character.isLowerCase(ch)) obj.add(validToken);; try{ d = Double.parseDouble(strToken.nextToken()); if(!((d % 1) == 0)){ obj.add(d); } }catch(Exception e){ } } for(Object o : obj){ if(!(o instanceof Double)) System.out.print(o + " "); } for(Object o : obj){ if(o instanceof Double) { System.out.println(); alert(d); } } } public static void alert(double value) { System.out.println("double: " + value); } public static void alert(String value) { System.out.println("String: " + value); } }

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remote87

Level 18 , Sofia, Bulgaria

1 March 2021, 14:34

I'm starting to think that I don't fully understand the condition of the task. Shouldn't this code work as the task wants:

package com.codegym.task.task15.task1527;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.*;

/*
Request parser

*/

public class Solution {
    public static void main(String[] args) {
        //write your code here
        Scanner scan = new Scanner(System.in);
        String url = scan.nextLine();
        //remove part of the URL we don't need - everything before '?' inclusive
        String subStr = url.substring(url.indexOf("?") + 1);
        //remove '=' and '&' with the help of 2 temp strings
        String noEqualsSign = subStr.replaceAll("=", " ");
        String noAmpersandSign = noEqualsSign.replaceAll("&", " ");
        String[] elements = noAmpersandSign.split(" ");
        double d = 0;
        String obj = "";
        if(elements[0].equals("obj")){
            if(elements[1].contains(".")) d = Double.parseDouble(elements[1]);
            else obj = elements[1];
        }
        for(String element : elements){
            if(Character.isLowerCase(element.toCharArray()[0])) System.out.print(element + " ");
        }
        System.out.println();
        if(d != 0) alert(d);
        if(!obj.isEmpty()) alert(obj);
    }

    public static void alert(double value) {
        System.out.println("double: " + value);
    }

    public static void alert(String value) {
        System.out.println("String: " + value);
    }
}

Guadalupe Gagnon

Level 37 , Tampa, United States

1 March 2021, 15:16

You still have a problem in which the code can't tell which are arguments and which are params. Take this String for example: "name=lupe&obj&month=mar&country&pet=mex&obj=pet&male=yes" When you remove all the "&" and "=", the result will be: "obj name lupe month mar country pet mex obj pet male yes" Given the second String, what are you supposed to print and what are you suppose to send to the Alert method? The correct output would be: name obj month country pet obj male String: 3.14

Guadalupe Gagnon

Level 37 , Tampa, United States

27 February 2021, 17:13

I see you are putting all kinds of Sys.out statements throughout your code for testing purposes, and even setting a default value to test instead of having to enter a string every time you want to test the program. Take a look at this help question I asked back when I was going through the course. The task is not important, but the use of a "debug" mode I implemented. It is very useful as it can turn on the debug mode for testing, then turn it off for validation on one line: look at debug I created this because I used to do the same exact thing. Then, when I was sure that the task conditions were satisfied, I would have to comment out or delete all those testing lines I added. It started becoming a real pain in the rear, after failing, having to add them all back in, try something new out, comment out/delete them, fail validation again, put them back in etc.

Nouser

Level 36 , Germany

27 February 2021, 13:30

In each while loop iteration you read two two tokens (lines 23 and 28). 1st iteration: lvl, 15 2nd iteration: view, name 3rd iteration: Amigo that's for sure not what you expect. Easiest fix would probably be to nest two Tokenizers (outer looking for &, inner for =). Or you use split, that's a lot easier.

remote87

Level 18 , Sofia, Bulgaria

27 February 2021, 13:36

I tried another approach ( EDITED ), I pass the two tests, shown in the example, but when validate - no passing the task...

Nouser

Level 36 , Germany

27 February 2021, 13:57

the new code didn't spit out the obj parameter when I tried. And I think it will not detect .5 or 1. as doubles. Keep it simple, try first to get the part from the ? on. From the result get all parts between the & Then you can check if there is a = in the resulting parts, if obj is present and whatever. When mixing this all you intruduce a lot of problems. have a look at the output of that

for (String s : url.split("\\?")[1].split("&")) {
    System.out.println(s);
}

instead of printing you could do another split...

Guadalupe Gagnon

Level 37 , Tampa, United States

27 February 2021, 17:23

I like what you did at line 15, by throwing out everything prior to the "?". Good technique ignoring what the task doesn't need. I agree with Nouser in that the tokenizer is too ambiguous. Also keeping it simple. After splitting the String by "&", you can then split each result by "=". This would leave the parameter, to be printed, always in the [0] index, and you only need the value at index [1] if the parameter is "obj" saved until after printing all the parameters.