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53 lines
1.7 KiB
53 lines
1.7 KiB
1 year ago
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## StarUtils
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### Instructions
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Now, some utils method for our class.
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First, the `toString` method which will return a literal version of our class. The format is the following : `<name> is positioned at (<x>, <y>, <z>)`. The printed double will be with 3 decimals.
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Then, the `equals(Object object)` method which will return trus if all properties of the object as parameters are equals to the current object.
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As we have rewritten the `equals` method, we need to rewrite the `hashCode` method. This method returns an integer. If two objects are equals (using the `equals` method), then the results of their hashCode method should be equals.
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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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CelestialObject celestialObject = new CelestialObject();
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CelestialObject earth = new CelestialObject("Terre", 1.0, 2.0, 2.0);
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CelestialObject earth1 = new CelestialObject("Terre", 1.0, 2.0, 2.0);
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System.out.println(earth.toString());
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System.out.println(earth.equals(earth1));
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System.out.println(earth.equals(celestialObject));
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System.out.println(earth.hashCode());
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System.out.println(celestialObject.hashCode());
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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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Terre is positioned at (1.000, 2.000, 2.000)
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true
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false
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2129490293
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-1811995559
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$
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```
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### Notions
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[Equals](<https://docs.oracle.com/javase/10/docs/api/java/lang/Object.html#equals(java.lang.Object)>)
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[HashCode](<https://docs.oracle.com/javase/10/docs/api/java/lang/Object.html#hashCode()>)
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[ToString](<https://docs.oracle.com/javase/10/docs/api/java/lang/Object.html#toString()>)
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