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The solution is going to cover part three where we start setting up the game class.

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We'll start by defining the scoreboard field, a scoreboard needs to monitor the score of each team.

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So we're going to use a Hashmat because there's parity between team and integer data.

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Private Hashmat.

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The Hashmat is going to store team manager key value entries and it's going to be called scoreboard.

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The next step is to create a constructor, the constructor runs as soon as we create an object of the

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game class and when it runs, it will receive two parameters the home team and the away team.

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Now, inside, the constructor will set the scoreboard equal to a new object of the Hashmat class.

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And then I'm going to put two entries into the scoreboard.

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A home team that starts with a score of zero.

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And an away team that starts with a score of zero and now notice that I'm adding copies of each parameter

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to the Hashmat.

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That's because you don't want your keys to share the same reference as the outside variable that's being

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passed in.

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Otherwise, the set of each key can be affected if you change the outside variable, which is a security

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leak.

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You know what?

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Why don't I just show you really quickly instead of passing in copies, I'll pass in each parameter

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directly and I'll create a new object of the game class using the format.

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I left you all and learn the parts.

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OK, they're both of type team.

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Now we're going to pass into a new object of the game class.

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A lot of breakpoint.

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Step inside.

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And check it out, each key has the same reference as the outside variable that was passed in as a parameter.

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If I update one of the objects, I'll change the house name for whom?

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Restart the debugger.

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The state of the key should get affected as well.

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That's not good.

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But if the constructor creates copies of each parameter, we can rest assured that each key store is

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a unique reference that points to a team copy.

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You can feel free to test that out yourself and monitor the references, but I'm going to move on enough

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about that.

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Now we want to create two getters, we'll start with the Geter get score.

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Which receives one parameter.

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The team who score you want to get.

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We'll get the score for this particular team.

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And it's going to get the score value for this particular team or will it we'll come back to this now.

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We are a center that updates the score for a particular team.

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It's going to be called set score and receive two parameters, the team for which you want to update

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the score.

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And the score itself.

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Then you can say scoreboard put.

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The following key value pair.

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Now, we're going to quality control this center later, because put either can add this as another

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entry in the hash map or it can update the entry that already contains this time object.

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Obviously, we want to update because the hash map should only have two entries.

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So for now, let's move on.

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Now we're going to to get her called get team that receives a parameter string name.

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We'll come back to this in the next video for now, just return null.

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And now you might be asking, should there be a set team setter, no.

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It's impossible to update a key after you add it, you can remove a key and then add another one, but

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you cannot change a key.

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It's not possible.

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All right, we're going to wrap up this video by testing the getters and setters, I'll get the score

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for Gryffindor.

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I'll set the score for Gryffindor to 10.

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Spoiler alert, none of these should work, so here's why I'm going out to break points.

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I'll step in to get score.

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The parameter we passed in has this reference which doesn't match any of the references in the hash

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map.

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And unless you define an equals method, Java uses the default equals method to compare to objects,

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which is why I can't find anything in the Hashmat that matches the parameter and returns no.

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Is that really the issue?

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We'll find out soon enough.

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Now, what would happen here, once again, the reference being passed and doesn't match any of the

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references in the Hashmat.

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So instead of updating the entry that already contains this theme object, it's going to think it's

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a new key and add another entry to the hash map and that's also not good.

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Java's using the default equals method to compare team objects.

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So we need to provide our own equals method that allows Java to compare to objects based on their fields,

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not the reference.

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The equals method needs to return a boolean.

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And receives an object.

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What's the type of that object?

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We don't know, it can be any object.

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First, we're going to check if the object that we're comparing against is no, because if it happens

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to be null, then there's no way it equals the object that's calling this method.

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Let's assume the object, is it?

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No.

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Then we need to check if it isn't of type team if the object isn't an instance of the team class.

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OK, so at this point, the object, is it no, it is an instance of team, so we can typecast it to

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type team.

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And finally, we need to check if the objects fields are equal to the current object that's calling

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this method, we need to compare the house return.

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This thought house equals timecode house.

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We need to compare the keeper.

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This storekeeper equals team goalkeeper.

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And how do we compare the array, remember, we can use arrays not to string.

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The new string is going to convert the contents of the array into one long string, and so if the two

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happened to share the same string, then they must have the same elements.

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And that's a.

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And so now I guess it should work.

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Let's run the code.

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And it still doesn't work.

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Hmm, well, test out the setar.

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Same thing.

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I'm pretty sure we defined our equals method perfectly.

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It compares to objects based on their fields.

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Those two objects, one hundred percent have the same fields.

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So why isn't Hashmat able to retrieve the key?

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For Hashmat to retrieve a key, it's not enough for an object to be equal to it.

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It must also share the same hash code.

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You're going to learn more about hash codes in the next video.