Global Positioning System Reference
In-Depth Information
Chapter 1
Software Objects and
Real-World Representations
1.1
Introduction
This chapter draws an analogy between objects in software development
and electronic devices, and to physical objects in general.
remote control Objects can be controlled by an application via appli-
cation programming interfaces (API) similar to controlling a television set
via a remote control. Every button invokes a \method" on the electronic
device, while the functionality is hidden.
We introduce a video application to demonstrate the difference between
developing programs and developing objects. The virtual machine repre-
sents the actual programming environment referencing (external) objects
with built-in functionality. This demonstrates one design intention of the
topic, to make object and application development as independent as pos-
sible.
This method is not limited to devices|any other technical construction
can be modeled by a software object. For example, a car is an object that
can be perceived externally, operated internally from the driver's seat, and
tuned internally under the hood. Programming a car should be closely
related to building a car in order to reflect real car behavior. Then, a
trac application can make use of a car class to instantiate a number of
cars.
In the development of our methodology, we look at how scientists model
the world. Physicists have actually re-engineered the behavior of physical
objects in general|not only man-made devices and machines. The exter-
nal characteristics of a stone are simple to describe. Yet, it took centuries
to understand its inner structure and its behavior, for example, in a grav-
itational eld|the external environment. This behavior can be simulated
with mathematical formulas.
3
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