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This video is going to cover the solution for part five based on the requirements we can define for

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fields private.

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Long time stamp.

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Private string ID, by the way, the reason this is a long is because time stamp values can get really

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large and then we'll say private double amounts.

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And now the type field can be one of two values, withdraw and deposit.

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So what I'm going to do is create an enum named type.

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With two constants withdraw and deposit.

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And Harold, declare a private field.

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Of type, type, named type.

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Now, a lot of constructor public transaction they receives for parameters.

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On second thought we can just auto generate this.

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All right.

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We'll add a copy constructor by copying this one.

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And instead of receiving values from four different parameters, we're going to receive values from

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a source object transaction source.

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This duct tape equals sauce, duct tape, source timestamp, source that I.D. and sauce that amounts.

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OK, now we're going to auto generate the getters and setters.

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Pretty easy.

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And now back on learn the parts you go here.

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Task number six was to convert the time stem field into a debt.

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Accordingly, if we scroll back to the requirements.

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Remember, you should always write unit tests for logic that is considered meaningful.

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So inside of the test folder, we're going to create a file named transaction.

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Tests.

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And I believe there was something on there in the part we had to import.

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Let me just have a look.

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And indeed, we did will import the following snippet.

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We'll use autocomplete to get rid of these errors.

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OK.

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We should be good.

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OK, now what we want to do is unit test our capability of converting this long value into a date.

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So I'm going to create a unit test.

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Public void.

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Correct date test.

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And now, if we go to any Web site that converts long values into a date, we can convert this one time

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stamp to human dates and we get back January 7th, 2019.

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So that means that we need to assert assert equals.

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We're expecting a value of, oh, seven.

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01 2019.

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When we call transaction date return dates.

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A method that does not exist yet, so back here inside of transaction Java.

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We're going to write code to make the test fail.

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So I'm going to write public string return dates.

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For now, just return high.

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And if you go back here.

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Figured the test fails now we just got to write code to make it pass.

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I left you a lot of hands on during the part, so if you were to look at the documentation, the date

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constructor returns a date based on the number of milliseconds since 1970, but our long value represents

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the number of seconds since 1970, so all we got to do is say.

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Dates date will create a new object of the debt class.

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For now will pass in the time stamp, which is the number of seconds since 1970.

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But remember, it's expecting the number of milliseconds.

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So what we're going to have to do is multiply by a thousand.

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So now we have our data object, we just got to format it into a string and we've already done this

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like two sections ago.

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So I'm going to skip the explanation and we'll go ahead and just create a new object of the simple date

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format class.

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And we're going to format our date to be in the form day, month, year.

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And using this format, we can format our date into a string.

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Perfect.

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Let's run our unit test.

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Go back to transactional tests, run the test.

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And we get an error.

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Expected.

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Negative 2013, but was.

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Oh, seven, oh, this is seven minus the one minus 2019.

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This should be a string.

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Well, we run our tests.

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And we're good.

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OK, now Task nine was to override equals and hash code, you can just generate them.

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Calls and hash code.

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OK.

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Import the object class.

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And now we want to make sure our objects are sortable from lowest time stamp to highest timestamp.

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And in order to sort our objects, they need to be comparable.

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That is, every transaction needs to implement the comparable interface implements comparable.

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And because we implemented the interface, we're signing a contract of behavior that forces us to override

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every method inside this interface.

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There is only one method, you know it very well, it's compared to.

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Compared to expect an integer, that integer is the result from comparing double dot compare.

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From comparing the timestamp of the current object, this timestamp against the timestamp of the one

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being passed in.

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This is going to be useful once we have hundreds of transactions inside of an array, the array is going

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to use this method to compare it to transaction objects at a time and based on each comparison, it's

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just going to know how to sort from lowest to highest anyways.

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Final task is to override to string.

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So we'll just generate it.

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But we're not going to use this format.

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Just copy the one from lowering the parts.

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Copy this over.

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And here will say.

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Return dates that start return date.

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OK, the final step is to always apply quality control in case the data being entered is faulty.

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You just never know.

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There's three hundred rows.

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One of the lines could be bad.

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We want to throw an unchecked exception, which basically forces the caller to fix their code and anticipate

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such a scenario instead of just passing it in that way, they're not sending over bad data.

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So we'll go back here.

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Now, time stamp is always valid because positive timestamp means seconds since 1970, and a negative

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timestamp is the time that comes before 1970.

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So that's fine.

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No matter what value we get, it shouldn't be null or blank.

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So our quality control that will say if ID is equal to known or indeed is blank.

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And also, the amount can't be negative, because the type, whether it's withdrawal or the opposite,

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it's going to determine whether we subtract or reduce the amount from the account balance.

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So we need to quality control that as well.

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Amount cannot be negative.

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In such a case, we need to throw a new illegal argument exception.

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Invalid params.

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We'll do the same thing inside the centres inside of it.

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We're going to make sure that the ID.

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It's not equal to no.

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Or if it's blank.

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In that case, we want to throw a new illegal argument exception.

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Invalid I.D..

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And we'll do the same thing inside of amounts, if amount is smaller than zero.

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There are new.

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A legal argument exception.

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Invalid amount.

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That's it.

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Moving on to part six.