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56 lines
1.7 KiB
56 lines
1.7 KiB
1 year ago
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## StarPlanet
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### Instructions
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Create a new class `Planet` in a file named `Planet.java`.
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This class inherits `CelestialObject`.
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It has one private property : `centerStar` of type `Star`.
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There are two constructors :
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- one with no parameters, which calls the superclass constructor with no parameters. In this case, the `centerStar` property is initialized with the default Star constructor.
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- one with many parameters :
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- `name`
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- `x`
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- `y`
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- `z`
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- `centerStar`
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which calls the superclass constructor with full parameters.
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We add a getter and a setter for the centerStar property (`getCenterStar` and `setCenterStar`).
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We will override the `hashCode` and `equals`, using the `centerStar` property.
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Finally, we rewrite the `toString` method. The returned String must have the following format : `<name> circles around <centerStar.name> at the <distanceWithCenterStar> AU`.
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The `distanceWithCenterStar` is computed using the `distanceBetween` method with the planet and its center star.##
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# Usage
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Here is a possible ExerciseRunner.java to test your function :
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```java
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public class ExerciseRunner {
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public static void main(String[] args) {
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Planet earth = new Planet();
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Planet naboo = new Planet("Naboo", 17.4389, 8349.1, 8943.92, new Star("Betelgeuse", 128.23, -12.82, 32.328, 1289.3));
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System.out.println(naboo.toString());
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System.out.println(earth.toString());
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System.out.println(naboo.getCenterStar().toString());
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}
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}
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```
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and its output :
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```shell
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$ javac *.java -d build
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$ java -cp build ExerciseRunner
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Naboo circles around Betelgeuse at the 12220.902 AU
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Soleil circles around Soleil at the 0.000 AU
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Betelgeuse shines at the 1289.300 magnitude
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$
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```
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