1
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And this solution, we're going to quality control the manager class, almost every bad invocation of

2
00:00:05,710 --> 00:00:10,780
a method or constructor is because the caller passed an illegal arguments or called the method that

3
00:00:10,780 --> 00:00:11,410
about time.

4
00:00:15,470 --> 00:00:20,090
So looking at the code, I can't think of any illegal arguments the user may pass that haven't been

5
00:00:20,090 --> 00:00:23,900
accounted for because the constructor doesn't receive any parameters.

6
00:00:23,900 --> 00:00:26,210
So there's nothing to really check and hear.

7
00:00:26,210 --> 00:00:31,820
If the user passes a null instead of an actual object, the code would already throw a null pointer

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exception.

9
00:00:32,659 --> 00:00:35,770
So throwing in a legal argument exception would be redundant.

10
00:00:36,590 --> 00:00:40,130
The same argument can be made for ad contact and remove contact.

11
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What about illegal state exceptions?

12
00:00:46,830 --> 00:00:51,180
Remember that illegal exceptions occur when an object calls its method at a bad time.

13
00:00:51,690 --> 00:00:53,000
What about ad contact?

14
00:00:53,610 --> 00:00:58,250
If there was a maximum number of contacts that you can store, then you could throw an illegal state

15
00:00:58,260 --> 00:01:00,420
exception for that particular scenario.

16
00:01:00,780 --> 00:01:05,340
But if you were to go back and read the requirements, there is no limit to the number of contacts that

17
00:01:05,340 --> 00:01:05,880
you can add.

18
00:01:07,810 --> 00:01:13,210
Although an object would not be in a valid state to call or remove contact if the Israelis, it is empty,

19
00:01:13,630 --> 00:01:20,020
if there are no contacts to remove now, array lists have an empty method that returns true if it has

20
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no elements.

21
00:01:26,950 --> 00:01:28,840
So we'll check if contact.

22
00:01:31,300 --> 00:01:32,230
That is empty.

23
00:01:35,070 --> 00:01:37,950
And in such a case will throw a new illegal -- exception.

24
00:01:41,330 --> 00:01:44,600
You can't call the remove method if there are no contacts to remove.

25
00:01:50,360 --> 00:01:55,220
OK, I can't think of any more safety checks that we need to apply so we can wrap up right here.