4.1

CelestialBody.java Class
The CelestialBody.java class is a serializable class that defines a generic celestial body, that can be a star, a
planet, or a moon.
The CelestialBody class declares the following constructor and methods:
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CelestialBody() constructor, to create a generic celestial body instance
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getId() method, to return an object identifier
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setId() method, to set an object identifier
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getName() method, to return an object name
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setName() method, to set an object name
Star.java Class
The Star.java class extends CelestialBody to create star objects.
The Star class adds the following constructor and methods:
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Star() constructor, to create star instances
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getCircumference() method, to return the circumference of a star
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setCircumference() method, to set the circumference of a star
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getSurfaceTemp() method, to return the surface temperature of a star
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setSurfaceTemp() method, to set the surface temperature of a star
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getPlanets() method, to return a list of planets that orbit a star
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setPlanets() method, to set the list of planets that orbit a star
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addPlanet() method, to add a planet to the list of planets that orbit a star
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removePlanet() method, to remove a planet from the list of planets that orbit a star
Planet.java Class
The Planet.java class extends CelestialBody to create planet objects.
The Planet class declares the following constructor and methods:
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Planet() constructor, to create planet instances
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getCircumference() method, to return the circumference of a planet
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setCircumference() method, to set the circumference of a planet
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getGravity() method, to return the gravity of a planet
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setGravity() method, to set the gravity of a planet
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getMoons() method, to return a list of moons that orbit a planet
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setMoons() method, to set the list of moons that orbit a planet
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addMoon() method, to add a moon to the list of moons that orbit a planet
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removeMoon() method, to remove a moon from the list of moons that orbit a planet
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getStarId() method, to return the identifier of the star that the planet orbits
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setStarId() method, to set the identifier of the star that the planet orbits
Chapter 7 Developing Plug-Ins
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