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We can also sort alphabetically.

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The goal of this lesson is to sort by class name and price.

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Open up the folder for this lesson by following this path inside the resources.

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The string class also implements comparable.

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It follows that the string class overrides compared to.

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The compared to method for string objects returns a negative number if the character in the first string

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has a lower Unicode value than the character in the specified object.

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Zero, if the strings are identical, which makes sense.

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And a positive number, if a character in the first string has a higher Unicode value than a character

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in the second string.

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We'll test the first case first, we have John and Amy, we'll call Amy compared to.

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John.

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The letter A. is expected to have a lower Unicode value than the letter J.

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So that's going to return a negative number.

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Perfect.

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Now, I'll compare Amy to Amy.

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Returns zero expected.

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Now, I'm going to compare John against Jane.

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JNJ, same Unicode value, but the letter O comes after a so we can expect a higher Unicode value perfect.

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And if we reverse it, we get a negative number.

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So based on this information that you just got, go back to the product application.

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And what I want you to do is sort the products by alphabetical order based on their class type, then

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sort the rest by price.

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Here are some hints you can get the class type by using get class and you can get the name of the class

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by using get class, get simple name.

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I'll give you the chance to pause the video and try this out.

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I hope you figured it out.

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So what I'm going to do is inside compared to I'll get the name of the current object.

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String class name.

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Is equal to this doGet class, that simple name.

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And I'll get the last name of the specified object.

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All right, now we're going to check if the class names aren't equal.

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If that's the case, we're going to return the result from comparing the first class name to the second

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one.

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Here we're comparing two strings, and if the two objects don't happen to share the same class, so,

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for example, if this is pants and this is shirt compared to is going to return an integer, that depends

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on the letters in each name.

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Let's test this out by running the debugger.

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These two objects don't share the same class.

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This is Pence, this is Schertz, the letter s is expected to have a higher Unicode value than the letter

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P.

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So this is going to return a positive value, which means shirt is going to come after pence.

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Now we're comparing pants and pants, the two pants are part of the same class, however, the price

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of the current object is higher than the price of the specified object.

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So compared to returns, a positive number.

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So it's going to sort the current object that come after the specified one.

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And so basically it's going to keep comparing each object against another object.

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First, it prioritizes alphabetical order.

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And if the two objects share the same class, then it's going to sort of by comparing the price of each

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product.

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Ultimately, we get an array where objects of different classes are sorted based on the class name,

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and every object of the same class are compared by price.

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The sort method can easily sort to comparable objects, sort uses compare to to determine how to sort

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your objects.

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And if the two objects don't have the same class, the one with characters that have a lower Unicode

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value are going to be sorted first.

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If the names happen to be equal, then the objects are compared based on their price.

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As a result, our comparable objects are sorted based on alphabetical order and price.