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Hi there.

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So in the last lesson we looked at our response which was use for money plodding R.S. understrapper

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.

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We looked at several different data structures on Vinita class to mount a ghosty does not just right

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on for that we have this class called us collection's which is also from the Jellico jungle package

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.

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So we know that there is that collection interface which is singular and this one is brutal.

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And this glass is also very similar to the artist's glass.

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So it is a utility glass with lots of static methods on it helps us in doing stuff like soft things

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searching on there are also some other exotic methods which we are going to see and many of them at

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that's how excessive genetics notations.

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OK.

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So just don't worry about them.

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I need to be clear when we get there.

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So here in this demo how created this class called us collections them all under it is added to the

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collections package and everything will be demonstrated in the main method.

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So we'll be writing some code on some of the core in the interest of time has already been there done

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so with this doc.

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So the first method that I would like to demonstrate is idle.

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OK.

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And that takes two parameters.

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One is a collection and others.

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And Ari on all it does this I are in the means to that collection.

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OK.

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Undergirds a boolean flag.

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So here we are creating an instance of idlest and we are adding three elements.

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Raj John on one more John and we are also creating this are they OK.

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Honored has only one element on.

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So let's go ahead and enrich our alma mater.

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So let's just say I don't see a passing list on the second one is Ari managed to spend less now says

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UG on Goldsby is so much stronger.

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And you can see all the elements right.

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John and John on Anita has been added to the list.

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OK.

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Now you may recall this from our collection the is that there is a method called eye on right now that

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are all very big a collection it are a collection of this collection.

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OK.

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So that is for adding a collection to another collection and if you want to budak we can make use off

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of it is not as old as you have seen that in the last lesson and we have to just pass the RV right.

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So that can also be done.

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But this is likely to be faster than this approach.

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OK.

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So just keep that in mind.

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So that's the out on the matter.

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Our Next let's look at the Salk method.

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So we have looked at the Salk method in Addis.

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So it just looks identical.

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So this would just sort the elements.

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So in this case the parameter is just in last.

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OK.

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It's going to Sadako on this particular sock method they will use natural ordering which means that

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elements of the list must implement built into office.

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So let's just go ahead and simply invoke the sock method

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and that's all there is to it.

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So I didn't know.

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OK.

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And there is also another version which will take a competitor as an input in addition to the list in

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which I guess it would use the comparative foreshortening.

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OK.

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You can take a look at the Kodak.

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So that's the sorting method.

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Next let's look at binary search.

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Now if you recall binary search was also there not as glass.

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So it is also here and not connections.

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OK.

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And this is the definition of it.

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So binary search matter is making a collection and list here.

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And it is searching for the key.

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OK.

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Now one thing I want to tell about the saut is as you can see it is only for a list but it's not making

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any sense.

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The reason for that is if you want a softer search you can actually use tricyclics and.

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OK so there is a reset so you can just make use of die.

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Now for Hasek said you cannot solve the elements if at all if you want to solve the elements of Hasek

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which I think you might never want to do.

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But if you want to do it.

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So there are two approaches.

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One is you can create a preset instance of instance on in the constructor one of the constructors accepts

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and collection so you can just pass a Hosack or you can create an idealist on bass and use one of the

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constructors which make a collection on pass Half-Chick and then you can invoke this method.

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So OK so sauteeing is only for it.

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And this particular in this particular class now come into a binary search site will be used for searching

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for a key in the event last year and the requirement is that it needs to be soccer and if it is it then

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it would be love.

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To me the convexity would be longer to make read and is the size of the list.

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Now you may recall that the list also has a called on base and that is linear.

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The complexity is linear.

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So this one is better than that.

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Hello are here the elements that require us.

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Each element has to be has to implement comparable indices.

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That's what this binary search method requires now.

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So the requirement is that the list and amounts have to be sorted.

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Now if it does not Sautter then the specification says that behavior of this method is undefined.

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OK so it might perform a search on it might return the index value so that I recall that it returns

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the index if the element is found on.

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It might return the value that it might find the element on it might return an index value even though

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the even though it's not charted but the it will not be a binary search so it might just do a regular

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linear search.

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But if binary search has to be pulled from then it must remain.

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Must be soccer.

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Once again it takes only a list I'm not a set because how set is already really efficient it is.

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It has constant time on plexis before searching for an intermediate.

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Similarly research is also very efficient.

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It is my job to make.

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So it is on just similar to a binary search.

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So that's the reason they did not provide another matter just for sex.

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The regular set classes do not die.

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OK they're very fast for such a right set implementations.

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Regarding uniqueness and also fast lookups There is also a binary search matter for which Dick's competitor

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.

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OK so it picks a competitor to search for a D in the list of elements and uses the competitor to find

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out.

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OK so you can also read got from the API.

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So let's just go ahead and search for something that you didn't see says on gold space.

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Let's search for Mr John.

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Is John there.

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So this should done one.

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And so on here.

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Right.

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So that is because John is at an expedition 1 OK so surgery and so fast.

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An explosion.

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So that's about the search.

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Now there are a bunch of matters that are very straightforward.

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So let's just go ahead and look at what they do.

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And you should be very straightforward.

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Just common this.

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Ugh.

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OK so let's just go ahead and look at each of them at us.

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So the first one is the worst as you may expect it will just leave the elements in the list.

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OK what was the list.

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Next this VOP method.

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It basically swaps two elements.

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It's index and swaps them under is and method call frequency.

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It just looks for this particular element and tells us how many times it appears in the list.

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Next the shuffle exhibition closes the list.

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So let's just go ahead and run them on we can discuss the book.

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Here it is first the reverse list.

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So this was the list on a thought John.

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John onrush.

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So this is the reverse list Saroj.

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John John and Anita Kay.

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All we are doing is invoking the article we were smattered on passing list.

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Next is the worst.

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Also written and so quiet so just keep that in mind it's just going to work on this list.

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Next to a swap matter.

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We are into changing the elements of zero on 3 so 0 is Rotch and 3 is unequal.

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So as you can see here that Adman's got swapped.

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Or maybe this list next is a frequency we are searching for John and John is appearing twice.

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So just bending to next with a shuffle shuffle us and shuffling shuffling got.

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OK if you run it one more time you may see a different order.

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There you go.

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Soit is mainly useful.

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One instance where it can be used for example if you are implementing some kind of a card game.

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If you want to shuffle the cards you can make use of this.

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OK but parts will be inside the list or if you are holed up in some kind of a site.

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If your home page displays a list of items so the list of items can be there for the entire day.

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I know for each Oxus if the user is performing that is refreshing the home page.

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You might want to just shuffle the list and show it to the user that made the list looks more are refreshed

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and start off being stale so that you can you can make use of shuffling.

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OK now so does the shuffling list on this Mock's one really just shouldn't go Max.

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Element excessive or the maximum element of the given collection.

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So does returning the max element.

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And for that it makes use of the natural ordering off its elements.

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So if you look at the natural order in here Raj is the Max.

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Max enemy.

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Anita is the middle of me so it makes use of Doc max and min and so Dodo's max and min.

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So next let's look at this method called less Singleton not a singleton method it takes an element undertones

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and set on the central how this particular element is really how any one element on the set is immutable

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.

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Which means that you cannot add any elements to it.

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And this is one good idea.

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We know that there is more on matter when you take a collection and really try to remove the elements

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in the collection from the current action.

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Not that's all it does.

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I mean if you want to if you want the collection in book collection to have only a single element then

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you can make use of this kind of method.

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This idiom can be used for that.

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Otherwise you will have to create a collection externally.

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Then our Jaun then Pasdar which looks a bit unclean.

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So this is a more elegant way to do it.

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And then there are also other methods like Singleton lists which were written in just hundreds of Singleton

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map also which takes a key value pair of regions and map which has a single mocking.

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OK so that's the singleton class.

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Our next looks you'll get this method called less on modifiable collection.

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OK.

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So let's look at an modifiable collection.

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So let's just say

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it's just an modifiable.

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OK.

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Now this matter basically as the name suggests it returns send an modifiable view of the book collection

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which means that it returns a collection.

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But that particular connection is not modifiable.

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OK.

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You can not add any elements to it.

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OK.

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You can even modify it.

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So it would be useful if you want to provide your client next to you or is an API.

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Your clients are accessing your methods.

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And if you want to provide only read access and you are in denial collections so you might be using

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some collections within your core implementation.

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But if you want to provide on the read only access then you can make use of this method.

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And with that they can only read the elements of your collection but there will never be able to modify

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the collection.

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So let's just go ahead and actually try this or let's just print this once.

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OK so if you want to search for something say

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so you want to search for Annita

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on it it's true.

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OK.

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So here in this case when the executor remore on John Mustoe got deleted.

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So let's just go ahead and actually add John and it should give us an error because this is an modifiable

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.

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So let's do this.

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OK so John is not there but we are trying to get him and we try to do this sort whosay unsupported operation

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exception.

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So you can never do it but you can do something like this.

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This can be possible.

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You can add something to the list here and then the element will get added to the on modifiable collection

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return collection.

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And as you say

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if I copy this suit to you on it now you can see that John has been on it.

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It's just that using this particular reference you cannot add anything normally to your clients.

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You would just do it under this reference.

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OK so this is not accessible anyhow.

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So but this is just for your information.

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So far all that debate is implemented is it uses a technical composition and forwarding.

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We may discuss it later in a separate item in a separate lesson.

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But the way it works is for all the read operations it will just delegate the control to the internalness

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but for all other operations it will run unsupported operation exception.

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Next issue could the court will hear this and this is creating an instance of an modifiable collection

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and if you look at a modifiable collection you can see that all of these are real operations.

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And if you invoke them it is actually invoking the the enclosed Amato's the the metal from the end glose

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Plus which is which is the input parameter.

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OK so that is just simply forwarding.

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If you can more easily it's going to invoke the easy method and of the input.

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OK so I'm just quoting the control bark for other methods.

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Like if you want to do it during that duration if you are calling monitor echoes the unsupported operation

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exception OK.

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Even for our clothes on supported operation exception.

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So that's called us imposition on forwarding.

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I need to just the decorator pattern on later where we will most likely discuss an item from Africa

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to Java where they will get back to this particular class.

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And that's about it.

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So just go ahead and look at the API iron when you're looking at the API.

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You may see some methods that start with the key but empty like empty list on those matters will be

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discussed in a subsequent lesson where we will be discussing an item from Effective Java undoctored

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.

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But very briefly not super important but I will be discussing that on other than that you may also find

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some moderates which started the T-Bird check.

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I'm going probably about them after we are done with generics.

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You may come back and look at those methods on that because they related to generics by that related

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to type safety.

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But once again I don't think those are that important maintenance.

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Finally there are some methods synchronized methods which start with a key and organized on those very

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well.

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And if you look on the chapter that's about it.

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Thank you.

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And you can find a code in the resource section.

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Happy coding