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All right, so we're done the hard part, we're done designing all of our classes, we wrote all of

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our unit tests.

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Now we just glue everything together inside men.

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So the first task was to create a new bank object.

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We're done that already.

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And the second task was to define a method that creates an account object and returns it.

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So what I'm going to do is define a public static method that returns an account.

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Called Create Object.

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And this method expects an array of string values, and from these values, it's going to create an

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object.

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Now you can expect the era of string values to have four elements.

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For example, let me just copy and paste one of those as a comment into here so you can expect an array

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with four elements where the first element tells us what kind of object we want to create, whether

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it's checking savings or loan.

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The second, third and fourth elements are actually used to create the object.

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So what we can actually do here is approach this one or two ways.

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We could create a switch statement that compares the first element against three possible cases.

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Case checking.

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And here we would create a checking object.

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Based on these values, we could do case savings.

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And create a Settings object.

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Or we could even do case lone.

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And then create a lone object.

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There is a reason why I don't like this method, and that's because it promotes copying and pasting,

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because if you think about it, let's just say the case is checking, then here you would just return

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new checking.

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Value add index one.

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Index two and three.

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There you would say, double that price double from the string value because our constructor expect

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to double.

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Now, so far, it's fine, but the issue is that savings and loan, they have the exact same constructor

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as checking.

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So you could literally just copy and paste this.

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And then just change the class name.

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But you know, me, I'm not a big fan of copying and pasting in this case, I could permit it because

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it's not always guaranteed that different classes are going to have the same constructor.

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But in this case they do.

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And you know me, I'm not a big fan of copying and pasting.

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So what I'm going to do is actually show you a dynamic way of creating objects.

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Go back to learn the part, I left you the syntax right here.

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Well, it over.

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So here I'm going to return.

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Following.

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First, you want to specify the class that you want to create an object from the class name includes

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the directories that you have to drill into until you get to it.

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Let's just say I want to reference the checking class.

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We would need to drill into source dot main notice here.

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It's not slight.

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That's just how you need to pass it into four name.

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So I would need to go to source Typekit main Typekit model.

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Typekit account.

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And here I would use Typekit checking.

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So to the string, I'm going to append dot checking.

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But obviously, we don't want to do that.

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We want to put values at index zero.

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So here we're specifying the class that we want to create an object from.

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This could be either checking savings or loan.

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And then we want to get the constructor for that class.

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Lucky for us, checking savings and loan, all of them share the same constructor string string double.

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And this line is where you basically pass parameters into the constructor.

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Here I'll pass.

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The idea?

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The person's name.

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And their balance.

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We're getting an error because our function expects us to return an account object, but this isn't

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sure what type of class you're creating an object from.

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So we need to type, cast to account.

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All right.

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And now we get a lot of exceptions.

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Now we're not going to throw all of these exceptions separately, that would be a pain.

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Instead, consider that the exception class is the base class for every single exception, whether it's

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checked or unchecked.

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In other words, we can treat every exception in Java as type exception.

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All right, now, the last thing I want to stress is let's assume we got these values into the values

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parameter.

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This would be no different than writing this return new checking.

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Values one, values two and values three.

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That's all.

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But since we want to avoid repetition, we don't want to say new checking, new savings, new loan.

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We can use this syntax to create objects on the fly to dynamically create objects.

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All right.

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What I want to do is confirm that this works, so I'm going to call this method for men.

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We'll say create object an inside or in a pass in an array of string values.

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Glenn Close, all of these and double quotes.

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We get an error because this throws exception.

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So what we're going to do is try to run the code.

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And catch the exception if it fails, so we'll catch the exception.

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And just print it for now.

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E get message.

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All right.

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And a breakpoint right here and make sure that an object gets created.

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We get an illegal argument, exception, argument type mismatch.

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Oh, that makes a lot of sense.

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Assume are creating an object of the checking class the constructor expect to string string and double.

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As specified here, string string double, but we're passing in string, string and string.

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Accordingly, it throws an exception.

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We need to pass this argument into a double before passing it into the constructor.

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OK.

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Really useful printing that message, by the way.

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Let's hope this works.

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And it did, but we don't see anything because we're going to have to store this in a variable, so

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what I'll do is I'll just say count.

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Account is equal to create object restart the runtime.

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And wow, this is flood.

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I'll put a random print statement.

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Try it again.

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There it is.

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Perfect.

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Now we have a way of dynamically creating checking savings and loan objects.

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All right now, task for us to define a method that loads every single account from the accounts text

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file into the bank.

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So what we're going to do is define a method called load accounts.

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We'll say public static void load accounts.

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It's going to receive an array list of account objects.

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And inside of this method, we're going to run through every single accounts in the accounts are list.

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And the reason why things aren't working is because we're going to have to import the aerialist class.

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And for every account inside of the accounts list, we're going to add it to the bank bank account accounts.

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This is great and all, but where are we going to get the ArrayList of accounts from?

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We need a method that returns every single account from the accounts that tax filing.

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So inside, man, Java will create another method called return accounts public.

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Static, this method returns in a rare list of accounts.

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It returns the error list of accounts that we're going to use over here.

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Return accounts.

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And I already know it's going to throw a file not found exception, so we'll just do it right now.

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And now inside this method, we're going to create a new object of the final input stream class fan

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input stream if this is equal to new file input stream and this file input stream is going to connect

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to the accounts file.

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And then we're going to create a new object of the scanner class scanner scan is equal to a new object

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scanner that receives input from the file input stream.

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OK.

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Don't forget to import it.

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And then we'll initialize the array, a list of accounts that we're going to populate array list accounts

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accounts is equal to a new object of the ArrayList class that can store account objects.

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And now we want to scan every single line in the accounts file, so we'll say, well, Scan Dot has

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next line while the accounts file has a next line, we're going to add it to the list of accounts accounts

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don't add.

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And expects an account object to here will create objects and create objects, expects an array of four

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values.

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And if you look back at the accounts file, every line contains four values separated by a comma.

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How do we split the line into four values based on a comma?

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We can scan the entire line, scanned our next line and then say, does split.

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And we'll use the comma separator to split the line into an array of string values.

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OK.

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The last thing we got to do is just return the error list return accounts.

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And it expects us to handle the exception here, but you know what, I think it might make more sense

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to go back to create objects and try to run the following code.

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If it happens to fail, our catch method is going to catch the failure catch exception.

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Here we're just going to print the message.

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E get message and return, no.

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We're catching the exception from inside the function, which means the function is not going to throw

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an exception anymore.

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Whoever is calling it, they can rest assured the exception gets caught in here and we don't need this

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anymore as well.

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OK, now what I want to do is call this method for men.

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We'll try to run the code.

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Return accounts will store the result inside of an ArrayList variable that can store account objects.

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And if the code happens to fail, we're going to catch the file not found exception and print the message.

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E get message.

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I'll put a random prince statement before starting the debugger.

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And if everything works, we should see 16 elements.

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So we'll debug the runtime.

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Step over.

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And indeed, we do.

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This is perfect in the next video, we'll continue the remaining tasks.