Polymorphism - Java Software Solutions: Foundations of Program Design - page 533

Summary of Key Concepts

A polymorphic reference can refer to different types of objects over time.

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The binding of a method invocation to its definition is performed at run
time for a polymorphic reference.

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A reference variable can refer to any object created from any class related
to it by inheritance.

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The type of the object, not the type of the reference, is used to determine
which version of a method to invoke.

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An interface name can be used to declare an object reference variable.

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An interface reference can refer to any object of any class that implements
that interface.

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A parameter to a method can be polymorphic, giving the method flexible
control of its arguments.

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Implementing a sort algorithm polymorphically allows it to sort any
comparable set of objects.

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Polymorphism allows us to apply a consistent approach to inconsistent
behaviors.

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We should hone our design senses to identify situations that lend them-
selves to polymorphic solutions.

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Establishing the relationship between a listener and the component it lis-
tens to is accomplished using polymorphism.

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A file chooser allows the user to browse a disk and select a file to be
processed.

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A color chooser allows the user to select a color from a palette or use RGB
values.

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A slider lets the user specify a numeric value within a bounded range.

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Exercises
Visit www.myprogramminglab.com to complete many of these Exercises
online and get instant feedback.
EX 10.1 Draw and annotate a class hierarchy that represents various
types of faculty at a university. Show what characteristics would
be represented in the various classes of the hierarchy. Explain
how polymorphism could play a role in the process of assigning
courses to each faculty member.