Enums, mutable fields
Look at second message
class myClass{
public static void main(String[] args) {
// Test the EngineType enum functionality
EngineType engine = EngineType.V8;
// Display engine details
System.out.println("Engine: " + engine.name());
System.out.println("Cylinders: " + engine.getCylinders());
System.out.println("Load Capacity: " + engine.getLoadCapacity());
// Start the engine
engine.startEngine();
// Try starting it again (should show already on)
engine.startEngine();
// Stop the engine
engine.stopEngine();
// Try stopping it again (should show already off)
engine.stopEngine();
}
public enum EngineType { V2(2, 1000), V6(6, 3000), V8(8, 4000), V10(10, 5000), V12(12, 6000); private final int cylinders; private final double loadCapacity; private boolean engineState; // mutable field // Constructor for enum constants EngineType(int cylinders, double loadCapacity) { this.cylinders = cylinders; this.loadCapacity = loadCapacity; this.engineState = false; // default engine state is off } public int getCylinders() { return cylinders; } public double getLoadCapacity() { return loadCapacity; } public boolean isEngineOn() { return engineState; } public void startEngine() { if (!engineState) { engineState = true; System.out.println(this.name() + " engine is starting."); } else { System.out.println(this.name() + " engine is already on."); } } public void stopEngine() { if (engineState) { engineState = false; System.out.println(this.name() + " engine is stopping."); } else { System.out.println(this.name() + " engine is already off."); } } } }
public enum EngineType { V2(2, 1000), V6(6, 3000), V8(8, 4000), V10(10, 5000), V12(12, 6000); private final int cylinders; private final double loadCapacity; private boolean engineState; // mutable field // Constructor for enum constants EngineType(int cylinders, double loadCapacity) { this.cylinders = cylinders; this.loadCapacity = loadCapacity; this.engineState = false; // default engine state is off } public int getCylinders() { return cylinders; } public double getLoadCapacity() { return loadCapacity; } public boolean isEngineOn() { return engineState; } public void startEngine() { if (!engineState) { engineState = true; System.out.println(this.name() + " engine is starting."); } else { System.out.println(this.name() + " engine is already on."); } } public void stopEngine() { if (engineState) { engineState = false; System.out.println(this.name() + " engine is stopping."); } else { System.out.println(this.name() + " engine is already off."); } } } }
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Hey @Ricochet_Master! Please useTIP: Narrow down your issue to simple and precise questions to maximize the chance that others will reply in here./closeor theClose Postbutton above when your problem is solved. Please remember to follow the help guidelines. This post will be automatically marked as dormant after 300 minutes of inactivity.
OUTPUT:
Engine: V8
Cylinders: 8
Load Capacity: 4000.0
V8 engine is starting.
V8 engine is already on.
V8 engine is stopping.
V8 engine is already off.
The field engineState is mutable, even though it is in an enum.
Though this seems useful, is this an intended feature?, is it good practice?
it can be useful, but IMO that isn't good practice and will make your code harder to understand for others.
A better approach would be having a wrapper class that has an enum variable as one member and the mutable field(s) as other member
Oh, got it
Thanks a lot
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One of the quickest and cleanest explanations I have had
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