1
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The solution assumes that you're already familiar with the equals method.

2
00:00:21,690 --> 00:00:25,230
And to the equals method must return false if the parameters no.

3
00:00:25,500 --> 00:00:27,510
So if object is equal to No.

4
00:00:32,310 --> 00:00:33,450
Return false.

5
00:00:37,400 --> 00:00:42,470
It needs to return false if the parameter is not an instance of item, so if object.

6
00:00:44,350 --> 00:00:46,150
Is not an instance of item.

7
00:00:50,150 --> 00:00:51,290
Return false.

8
00:00:55,810 --> 00:01:00,100
Otherwise, at this point, we can typecast the parameter to the type item.

9
00:01:05,830 --> 00:01:08,710
And now we can compare every field from both objects.

10
00:01:10,160 --> 00:01:11,540
Return this thought name.

11
00:01:13,620 --> 00:01:15,030
Equals item name.

12
00:01:21,140 --> 00:01:26,150
And we'll return the bullying result from this stock price equalling item price.

13
00:01:31,190 --> 00:01:36,890
All right, now contains is going to compare every item object inside the array list against the parameter

14
00:01:36,890 --> 00:01:38,510
using the new equals method.

15
00:01:39,000 --> 00:01:41,540
If that's true, then our coach would finally work.

16
00:01:52,870 --> 00:01:58,810
And beautiful, it recognizes that the items list already contains the salary object and it didn't add

17
00:01:58,810 --> 00:01:58,930
it.

18
00:02:00,220 --> 00:02:04,780
For the sake of visualizing the runtime, I'll add a few break points and launch the debugger.

19
00:02:22,590 --> 00:02:25,980
At first, the list doesn't contain anything, so we can just step over it.

20
00:02:30,230 --> 00:02:31,550
And add the first item.

21
00:02:35,120 --> 00:02:41,420
OK, now the area list already contains the celery object, let's see if this works, I'm going to step

22
00:02:41,420 --> 00:02:45,380
into contains it should run the equals method for the first element.

23
00:02:49,510 --> 00:02:53,700
Watch and see that it runs the equals method for the item object.

24
00:03:04,560 --> 00:03:07,260
The parameter that we're comparing against is not No.

25
00:03:10,430 --> 00:03:12,320
It is an object of the atom class.

26
00:03:17,290 --> 00:03:19,990
The fields between those two objects are equal.

27
00:03:24,090 --> 00:03:26,250
So the equals method is going to return, true.

28
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So the aerialists does contain the object.

29
00:03:40,260 --> 00:03:45,450
And because the array list already contains this object, we're just going to break the function by

30
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returning false and that is all.