OOAD Overview - Obje Orie d Analysis And De ct nte sign Ove w rvie 1 What is an Obje ct lf-containe package with d A se spe variable(attribute and cific

OOAD Overview - Obje Orie d Analysis And De ct nte sign Ove...

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1 Object Oriented Analysis And Design Object Oriented Analysis And Design Overview Overview
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CIS 554 2 What is an Object?A self-contained package, with specific variables (attributes) and methods (behaviors).An object stands alone.An object’s implementation is purposely hidden from us.
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3 What is an Object?
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CIS 554 4 What is an Object?
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CIS 554 5 What is a Class?
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CIS 554 6 What is a Class?
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7 What is a Message?
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CIS 554 8 Example Object Description - provides time of day, and an audible indication of a user-defined timeduring the day Interface Inputs - timeof day, alarm time Outputs - timeof day, audiblealarm Attributes hour hand, minutehand, second hand, bell Behaviors Increment hour, increment minute, increment second, sound bell
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CIS 554 9 Key Object-Oriented Characteristics Encapsulation (Information Hiding) Attributes and behavior arerolled into theobject, and hidden from therest of us. Only thing exposed is the“public interface” Inheritance Creating oneobject from another, already defined object, adding to its capabilities and public interface.. Polymorphism Specific object behavior is determined within a run-timecontext. An object can “morph” itself based on thecontext in which it is currently used. Re-useable With very discreteand finitecapabilities, objects can beused in other parts of the system, or within other systems.
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CIS 554 10 Clock Object How does our clock rate as an object? Encapsulation Provides hour, minutes and seconds, and an alarm. Do weknow themechanisms for incrementing hours, minutes and seconds? Sounding the alarm? Inheritance Wecan useour simpleclock object to createadditional, morecomplex objects requiring time. E.g., chronograph, washing machinetimer controller, etc. Polymorphism Not applicable Re-usable Our clock can beused in thousands of applications as is. Wecan useit in any application that requires us to keep track of time, and alert us when a certain timehas occurred.
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CIS 554 11
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