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Why do we need Set and Map for Java Enum


Why do we need Set and Map for Java Enum

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Why do we need Set and Map for Java Enum
Tag : java , By : Tonci Grgin
Date : November 24 2020, 01:01 AM

To fix this issue Consider a scenario where you are defining flyweight for each shape object like:
public enum SHAPE {
    TRIANGLE, RECTANGLE, SQUARE, HEXAGON;
}
public double calculateArea(SHAPE shape) {
    Figure figure = map.get(shape);//you dont create object but take it from a map
    return figure.calculate();
}
enum COLORS {
    RED, BLUE, GREEN
}

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java 1.6 enum issue com.ibm.ws.webservices.engine.enum.Style.WRAPPED


Tag : java , By : artifex
Date : March 29 2020, 07:55 AM
Any of those help I have found the solution to my question by myself, though it took long time, so here is the solution.
change com.ibm.ws.webservice.engine.enum to com.ibm.ws.webservice.engine.enumtype add "com.ibm.ws.webservices.thinclient_7.0.0.jar" to your classpath and recompile the code.

What is the pros and cons between Enum and enum-based class implementation in Java?


Tag : java , By : user130518
Date : March 29 2020, 07:55 AM
Does that help In Java, Enum types act as a class that is declared with their unique name. It is pretty much like the any other class that is designed to create constant values. Recently, I also came across to an info that before the declaration of Enums in Java, an enum like class was created. Just like the article that was suggested on this question, it seems that previous to JVM 1.5, class based enums were widely used.
You can check this source: http://javarevisited.blogspot.com/2011/08/enum-in-java-example-tutorial.html

Why the java method Enum.valueof invoke the enum type constructor?


Tag : java , By : Chris Tattum
Date : March 29 2020, 07:55 AM
I wish this help you It isnt the method valueOf that calls the constructor.
The constructor of an enum is called for every literal when the class is first used. So in your case thats before the first call to Enum.valueOf.

What is the best way to set class variable which is an enum based on some conditional logic on a dependent enum in java?


Tag : java , By : Matt Croydon
Date : March 29 2020, 07:55 AM
it helps some times I am trying to map values from one enum to the other based on some calculation or conditional logic that I need to perform to set the correct enum value for the class variable. How can I do this without using too many if/else, switch statements? , Using predicates as I said would look like this:
public enum Brand {
    MINI,
    FERRARI,
    PAGANI
}

public enum Engine {
    LEVEL1,
    LEVEL2,
    LEVEL3
}

public class Entry {
    public final Predicate<Car> pred;
    public final Engine engine;

    public Entry(Predicate<Car> pred, Engine engine) {
        this.pred = pred;
        this.engine = engine;
    }
}

public class Car {
    int model;
    int year;
    Engine engine;

    public void carEngineCalculator(Brand b) {
        Car mycar = new Car();

        List<Entry> cases = new ArrayList<>();
        cases.add(new Entry(c -> c.isSuperCar(b) && c.isCrazyGood(b), Engine.LEVEL1));
        cases.add(new Entry(c -> c.isSuperCar(b) && !c.isCrazyGood(b), Engine.LEVEL2));
        cases.add(new Entry(c -> !c.isSuperCar(b), Engine.LEVEL3));

        mycar.engine = cases.stream().filter(x -> x.pred.test(mycar)).findFirst().get().engine;

    }

    public boolean isSuperCar(Brand b) {
        if ((b == Brand.FERRARI) || (b == Brand.PAGANI)) {
            return true;
        }
        return false;
    }

    public boolean isCrazyGood(Brand b) {
        return false;
    }
}

How to use the value of a string in an enum as an input to output the rest of the data for that enum item in Java?


Tag : java , By : mckasty
Date : March 29 2020, 07:55 AM
this will help The collection Element.values() contains all the values of your enum class.
After the user gives input, loop through this collection and check the symbol property to find the element.
public static void main(String[] args) {
    Scanner reader = new Scanner(System.in);
    boolean found = false;
    do {
        System.out.println("Enter the symbol of an element in the periodic table. ");
        String input = reader.nextLine().trim();

        for (Element e : Element.values()) {
            if (e.symbol.equals(input)) {
                found = true;
                System.out.println("Element: " + e + " (" + e.symbol + ")" + "\nGroup: " + e.group + "\nAtomic Mass: " + e.weight);
            }
        }
        if (!found)
            System.out.println("That symbol is not valid. Please try again. ");
    } while (!found);
    reader.close();
}
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