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Question about the task

Shared list

Java Core, Level 7, Lesson 10

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1. Change the Solution class so that it becomes a list. (It must implement the java.util.List interface).
2. The Solution list should only work with Longs.
3. Use the original field.
4. The list will be used by threads, so you need to ensure that all the methods are synchronized.

Requirements:

The Solution class must implement the List<Long> interface.
The Solution class must have a private ArrayList<Long> field called original.
All of the List interface's overridden methods must delegate calls to the methods of the original object.
All of the Solution class's methods, except for the main method, must be synchronized

package com.codegym.task.task17.task1713; import java.util.*; /* Shared list */ public class Solution implements List<Long>{ private ArrayList<Long> original = new ArrayList<>(); public static void main(String[] args) { } public synchronized ArrayList<Long> subList(int a,int b){ return original.subList(a,b); } public synchronized ListIterator listIterator(){ } public synchronized ListIterator listIterator(int i){ } }

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Kotlet

Level 28 , Wroclaw, Poland

12 July 2019, 18:52

It should go like this (couple examples):

@Override
    public synchronized Long set(int index, Long element) {
        return original.set(index, element);
    }

    @Override
    public synchronized void add(int index, Long element) {
        original.add(index, element);

    }

    @Override
    public synchronized Long remove(int index) {
        return original.remove(index);
    }

    @Override
    public synchronized int indexOf(Object o) {
        return original.indexOf(o);
    }

Remeber that you must override all methods from list interface (ctrl+o in intelliJ).

Pandora

Level 17 , Stockholm, Sweden

23 March 2020, 13:55

Thanks for the examples!