CodeGym/Help with Java Tasks/What's the meaning of the last requirement?

Level 29

Wellington

04.04.2019
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What's the meaning of the last requirement?

Question about the task

Threads of a string or stringy threads? That's the question

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I am not sure what's the requirements want. To my understanding each method should show the text in the conditions which my code does, but it's not verified. Can anyone explain it please? Thanks.

1. The getPartOfString method must return the substring between the first and the last tab characters.
2. The getPartOfString method should throw an exception if it receives invalid data:
a) StringForFirstThreadTooShortException if the thread's name is FIRST_THREAD_NAME.
b) StringForSecondThreadTooShortException if the thread's name is SECOND_THREAD_NAME.
c) Otherwise, RuntimeException.
3. Implement the logic of the three protected methods in OurUncaughtExceptionHandler using the corresponding method calls according to the following patterns:
a) 1# : StringForFirstThreadTooShortException : java.lang.StringIndexOutOfBoundsException: String index out of range: -1
b) java.lang.StringIndexOutOfBoundsException: String index out of range: -1 : StringForSecondThreadTooShortException : 2#
c) RuntimeException : java.lang.StringIndexOutOfBoundsException: String index out of range: -1 : 3#

Requirements:

The getPartOfString method must return the substring between the first and last tab characters in the string passed as the first argument.
If the getPartOfString method receives invalid data, it should throw a StringForFirstThreadTooShortException if the thread's name (threadName) is Solution.FIRST_THREAD_NAME.
If the getPartOfString method receives invalid data, it should throw a StringForSecondThreadTooShortException if the thread's name (threadName) is Solution.SECOND_THREAD_NAME.
If the getPartOfString method receives invalid data, it should throw a RuntimeException if the thread's name (threadName) is neither Solution.FIRST_THREAD_NAME or Solution.SECOND_THREAD_NAME.
The getFormattedStringForFirstThread method must return a string built using the arguments and formatted in accordance with the pattern specified in the task conditions.
The getFormattedStringForSecondThread method must return a string built using the arguments and formatted in accordance with the pattern specified in the task conditions.
The getFormattedStringForOtherThread method must return a string built using the arguments and formatted in accordance with the pattern specified in the task conditions.

package com.codegym.task.task22.task2201; /* Threads of a string or stringy threads? That's the question */ public class Solution { public static void main(String[] args) { new Solution(); } public static final String FIRST_THREAD_NAME = "1#"; public static final String SECOND_THREAD_NAME = "2#"; private Thread thread1; private Thread thread2; private Thread thread3; public Solution() { initThreads(); } protected void initThreads() { this.thread1 = new Thread(new Task(this, "A\tB\tC\tD\tE\tF\tG\tH\tI"), FIRST_THREAD_NAME); this.thread2 = new Thread(new Task(this, "J\tK\tL\tM\tN\tO\tP\tQ\tR\tS\tT\tU\tV\tW\tX\tY\tZ"), SECOND_THREAD_NAME); this.thread3 = new Thread(new Task(this, "\t\t"), "3#"); Thread.setDefaultUncaughtExceptionHandler(new OurUncaughtExceptionHandler()); this.thread1.start(); this.thread2.start(); this.thread3.start(); } public synchronized String getPartOfString(String string, String threadName) { try { int start = string.indexOf("\t")+1; int end = string.lastIndexOf("\t"); String result = string.substring(start, end); return result; } catch (Exception e) { if (threadName.equals(FIRST_THREAD_NAME)) { throw new StringForFirstThreadTooShortException(); } else if (threadName.equals(SECOND_THREAD_NAME)) { throw new StringForSecondThreadTooShortException(); } else throw new RuntimeException(); } } }

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yz Backend Developer

18 December 2019, 05:09

yea u should use getClass.getSimpleName for nameofexception getCause for the cause of exception and getName for name of thread

Manish Sinha

Level 26 , london, United Kingdom

22 September 2020, 20:09

thanks zy for the hint.

yz Backend Developer

26 September 2020, 05:37

You welcome Manish!

Bill Wu

Level 29 , Wellington, New Zealand

12 April 2019, 02:57

solution

It looks like you have to use some methods from the original exception API to pass the verification. getCause/Message, getSimpleName, etc. Don't use substring

Oleh

Level 32 , Kyiv, Ukraine

4 April 2019, 23:44

Try to use Thread t and Throwable e to generate the String

Bill Wu

Level 29 , Wellington, New Zealand

5 April 2019, 02:33

Thanks for the hint, but I only passed the last one, and the other two still failed. I can't figure out why.

protected String getFormattedStringForOtherThread(Thread t, Throwable e, String string) {
        int i = e.toString().indexOf(e.getMessage());
        String s = String.format(string, e.toString().substring(10,i-2), e.getMessage(), t.getName());

        return s;
    }

    protected String getFormattedStringForSecondThread(Thread t, Throwable e, String string) {
        int i = e.toString().indexOf(e.getMessage());
        String s = String.format(string, e.getMessage(), e.toString().substring(33, i-2), t.getName());


        return s;
    }

    protected String getFormattedStringForFirstThread(Thread t, Throwable e, String string) {
        int i = e.toString().indexOf(e.getMessage());

        String s = String.format(string, t.getName(), e.toString().substring(33, i-2), e.getMessage());

        return s;
    }

I also changed my getPartOfString method to throw Excepton like this

throw new StringForFirstThreadTooShortException("java.lang.StringIndexOutOfBoundsException: String index out of range: -1");

Oleh

Level 32 , Kyiv, Ukraine

5 April 2019, 07:00

Exists simpler method to get name of the exception. Don't forget it's also a class and you can use e.getClass and then something else. In getPartOfString you don't need write message by yourself

throw new StringForFirstThreadTooShortException(e);

Bill Wu

Level 29 , Wellington, New Zealand

5 April 2019, 08:58

Thanks for your reply. I tried with your way to create Exception and get String with getClass method, but still fails.

protected String getFormattedStringForSecondThread(Thread t, Throwable e, String string) {
        int start = e.getClass().toString().indexOf("String");
        String s = String.format(string, e.getLocalizedMessage(), e.getClass().toString().substring(start), t.getName());


        return s;
    }

    protected String getFormattedStringForFirstThread(Thread t, Throwable e, String string) {
        int end = e.toString().indexOf(e.getMessage())-2;
        int start = e.toString().indexOf("String");
        System.out.println(start);
        String s = String.format(string, t.getName(), e.toString().substring(start, end), e.getMessage());

        return s;
    }

Oleh

Level 32 , Kyiv, Ukraine

5 April 2019, 10:08

Wow, it was hard debugging but i get it. I'am totally forgot that i added custom constructor to "ThreadTooShortException" classes. So without this constructor detailMessage didn't initializating.

And when you doing e.getClass.toString you pointing to null. There are two solutions: 1. Add constructor

public StringForSecondThreadTooShortException(Exception e) {
    super(e);
}

OR 2. get exception name by using

e.getClass().getSimpleName()

Oleh

Level 32 , Kyiv, Ukraine

5 April 2019, 10:11

Looks like validator doesn't check any messages, so "null" in solution without constructor will be OK.

Bill Wu

Level 29 , Wellington, New Zealand

5 April 2019, 19:10

Thanks for the reply. I did add the constructor before you mentioned, but still fails. So I contacted the developers, hopefully they can give me some ideas.