- Project Overview: Docgen 3:48
- Starting the Annotation - Declaration and Retention 4:15
- Declaring an Annotation 1 question
- Declaring an Annotation 2 objectives
- Finishing the Annotation - Targets and Elements 4:01
- Adding Annotation Targets and Elements 2 objectives
- Using a Custom Annotation 3:20
- Applying an Annotation 3 questions
- Introduction to Reflection 11:40
- Reflection Basics 2 questions
- Reflection Basics 2 objectives
- Using Reflection on Our Annotation 9:06
- Putting It All Together 4 objectives
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Using a Custom Annotation
3:20With our @Doc annotation written, we can now use it like any other. In this video, we'll apply the annotation to the MathUtils class and a few of its methods.
I'm back in our workspaces project and
we're ready to use our doc annotation and
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the MathUtils class.
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First, we'll need to import
the annotation itself,
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import com.teamtreehouse.docgen.Doc.
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We'll start by applying
the annotation to the class itself.
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And in this annotation, we'll need
to include just a description since
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parameters and
return types will not apply to the class.
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You can list the annotation on separate
lines if you'd like to keep it well
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formatted.
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I'll say that this is a Utility class for
commonly used math functions.
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Notice that I've had to
explicitly list D-E-S-C.
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Remember, the only time you can omit
the element name is when the element name
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is exactly value.
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Now, let's add some annotations to a few
methods and make some of them incomplete
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just to verify that our tool is able
to catch both successes and failures.
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For the triangle area method, I'll include
a description for only one parameter.
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So include our doc annotation,
I'll put this on three separate lines.
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For the description, I'll write that
it calculates the area of a triangle.
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I'll abbreviate here.
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For the parameters, again, I will include
a description for just one parameter.
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And again,
our params element is a string array, so
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I'll have to use array notation
with the curly braces.
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And for the returnVal, I will say returns
the calculated area of the triangle.
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Cool.
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For the distance method,
I'll make the returnVal an empty string.
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I'll include as its
description that it calculates
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the distance between the given points.
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I'll include descriptions for
both parameters,
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the first one being
the coordinates of one point,
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the second one being
the coordinates of another point.
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And finally, the returnVal, as I said,
I will leave as an empty string.
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As for the quadraticRoots method,
I'll leave this one out completely and
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go right to the epsilon method.
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For this one, I'll include only a
description since it has no parameters and
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is a void method.
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I'll say that this displays
the value of epsilon.
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The arePointsClose method
won't need documentation
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to pass our tools test since
it's a private method.
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And there you have it,
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a class that utilizes the annotation
that we wrote ourselves.
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The writing of the doc
annotation was fairly brief.
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The lengthier work for us will come in
the form of examining the presence of our
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annotation on classes and methods
through a technique called reflection.
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More on that next.
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