problem in 4th condition. help pls?

Question about the task

Writing our own ThreadFactory

Java Multithreading, Level 8, Lesson 4

Resolved

i don't know exactly where the problem is

In the Solution class, create a public static AmigoThreadFactory class that implements the ThreadFactory interface.
1. The implementation of the interface's method must create and return a thread that:
1.1. is not a daemon,
1.2. has a normal priority level,
1.3. The thread's name must follow the pattern "GN-pool-A-thread-B" where:
GN is the group name,
A is the factory number, which is incremented inside the class, starting from 1 (use AtomicInteger),
B is the thread number, which is incremented inside a specific factory, starting from 1 (use AtomicInteger).
2. Each factory must contain the thread group (ThreadGroup) it was created in.
3. The main and emulateThreadFactory methods are not tested.

Example output:

secondGroup-pool-2-thread-1
firstGroup-pool-1-thread-1
firstGroup-pool-1-thread-3
secondGroup-pool-2-thread-3
firstGroup-pool-1-thread-2
secondGroup-pool-2-thread-2

Requirements:

In the Solution class, you need to create a public static AmigoThreadFactory class that implements the ThreadFactory interface.
The AmigoThreadFactory factory must create threads that are not daemons.
The AmigoThreadFactory factory must create threads with a normal priority level.
The AmigoThreadFactory factory must create thread names according to the pattern "GN-pool-A-thread-B".
Each factory must generate threads with the group (ThreadGroup) it was created in.

package com.codegym.task.task28.task2802; import java.util.concurrent.ThreadFactory; import java.util.concurrent.atomic.AtomicInteger; /* Writing our own ThreadFactory */ public class Solution { public static void main(String[] args) { class EmulatorThreadFactoryTask implements Runnable { @Override public void run() { emulateThreadFactory(); } } ThreadGroup group = new ThreadGroup("firstGroup"); Thread thread = new Thread(group, new EmulatorThreadFactoryTask()); ThreadGroup group2 = new ThreadGroup("secondGroup"); Thread thread2 = new Thread(group2, new EmulatorThreadFactoryTask()); thread.start(); thread2.start(); } private static void emulateThreadFactory() { AmigoThreadFactory factory = new AmigoThreadFactory(); Runnable r = new Runnable() { @Override public void run() { System.out.println(Thread.currentThread().getName()); } }; factory.newThread(r).start(); factory.newThread(r).start(); factory.newThread(r).start(); } public static class AmigoThreadFactory implements ThreadFactory { private AtomicInteger counter = new AtomicInteger(1); private final AtomicInteger pool = new AtomicInteger(1); @Override public Thread newThread(Runnable r) { Thread thread = new Thread(r); thread.setDaemon(false); thread.setPriority(Thread.NORM_PRIORITY); String threadName = String.format("%s-pool-%s-thread-%s", thread.getThreadGroup().getName(), pool.get(), counter.getAndIncrement()); thread.setName(threadName); return thread; } } }

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Guadalupe Gagnon

Level 37 , Tampa, United States

14 August 2020, 14:48

Have you tried to increment the "pool" on line 53 as was done with "coutner"

Henrique

Level 41 , São Paulo, Brazil

14 August 2020, 14:54

Based on other help topics, I tried to do this inside AmigoThreadFactory class:

public AmigoThreadFactory(){
            pool.incrementAndGet();
        }

Didn't work. Also, I tried to place the AtomicInteger pool in the Solution class and it didn't work as well (pool is not reachable). So, absolutely no idea :/

Guadalupe Gagnon

Level 37 , Tampa, United States

14 August 2020, 15:04

Ok, actually, the variable pool is being used to number the individual factories. This means that it should be a class variable instead of an instance variable. It should also be incremented by 1 each time that a new factory is built. I would recommend creating a instance int to store the factory number to use in the output instead of pool.get().

Henrique

Level 41 , São Paulo, Brazil

14 August 2020, 15:10

Ok, trying to understand. So: 1. I create a private static final AtomicInteger pool = new AtomicInteger(1); in the Solution class? 2. How do I increment it by 1 each time that a new factory is built? Should I do this in Solution or inside AmigoThreadFactory class? 3. Where this instance int to store the factory number should be created and how to implement it? Sorry for asking like everything, but this topic has been really hard for me to understand.

Guadalupe Gagnon

Level 37 , Tampa, United States

14 August 2020, 15:20

I messaged you, but to answer these questions: 1) yes, static makes it a class wide variable now and it will be the same for every single object created 2) Either in the constructor or one of the non-static fields. Both of these places are only reached on object creation. 3) Inside the AmigoThreadFactory class. Make it a non-static field so that it is unique for each object that is created. Use the static pool field to set the value of this int.