Этот мощный Enum

Я считаю, что после просмотра теста не нужно больше объяснений 🙂

В этом параграфе я описал самый важный метод Enum, который мы получаем из-за использования ключевого слова enum.

Давайте посмотрим, что мы можем сделать с этим больше.

мои собственные методы

Перечисление не должно быть простым списком элементов. Вы можете добавить свой собственный метод в него или / и предоставить свой собственный конструктор.

Стоит отметить, что конструктор должен быть закрытым, и вы не можете запустить конструктор родителя (Enum), это будет сделано без дополнительных усилий.

Категория enum показывает, как это сделать:

package com.smalaca.enumeration.designpatterns;

public enum Category {

    CREATIONAL("Deals with object creation mechanisms, trying to create objects in a manner suitable to the situation."),
    STRUCTURAL("Eases the design by identifying a simple way to realize relationships between entities."),
    BEHAVIORAL("Identifies common communication patterns between objects and realize these patterns.");

    private final String description;

    private Category(final String description) {
        this.description = description;
    }

    public String describe() {
        return description;
    }

    public String getExample() {

        String example = "";

        switch(this) 
        {
            case CREATIONAL:
                example = "Builder";
                break;

            case STRUCTURAL:
                example = "Adapter";
                break;

            case BEHAVIORAL:
                example = "Strategy";
                break;  
        }

        return example;
    }
}

@RunWith(Parameterized.class)
public class CategoryTest {

    private Category category;
    private String description;
    private String example;

    public CategoryTest(Category category, String description, String example) {
        this.category = category;
        this.description = description;
        this.example = example;
    }

    @Parameters
    public static Collection<Object[]> dataProvider() {
    return Arrays.asList(new Object[][] {
            { 
                Category.CREATIONAL, 
                "Deals with object creation mechanisms, trying to create objects in a manner suitable to the situation.",
                "Builder"
            },
            { 
                Category.STRUCTURAL, 
                "Eases the design by identifying a simple way to realize relationships between entities.",
                "Adapter"
            },
            { 
                Category.BEHAVIORAL, 
                "Identifies common communication patterns between objects and realize these patterns.",
                "Strategy"
            }
        });
    }

    @Test
    public void getCategoryExplanation()
    {
        assertSame(description, category.describe());
    }

    @Test
    public void getExample()
    {
        assertSame(example, category.getExample());
    }
}

package com.smalaca.enumeration.designpatterns;

public enum Creational {

    ABSTRACT_FACTORY {
        @Override
        public String describe() {
            return "Provide an interface for creating families of related or dependent objects without specifying their concrete classes.";
        }
    },

    BUILDER {
        @Override
        public String describe() {
            return "Separate the construction of a complex object from its representation allowing the same construction process to create various representations.";
        }
    },

    FACTORY_METHOD {
        @Override
        public String describe() {
            return "Define an interface for creating a single object, but let subclasses decide which class to instantiate.";
        }
    };

    abstract public String describe();
}

@RunWith(Parameterized.class)
public class CreationalTest {

    private Creational designPattern;
    private String description;

    public CreationalTest(Creational designPattern, String description) {
        this.designPattern = designPattern;
        this.description = description;
    }

    @Parameters
    public static Collection<Object[]> dataProvider() {
        return Arrays.asList(new Object[][] {
            { 
                Creational.ABSTRACT_FACTORY, 
                "Provide an interface for creating families of related or dependent objects without specifying their concrete classes.",
            },
            { 
                Creational.BUILDER, 
                "Separate the construction of a complex object from its representation allowing the same construction process to create various representations.",
            },
            { 
                Creational.FACTORY_METHOD, 
                "Define an interface for creating a single object, but let subclasses decide which class to instantiate.",
            }
        });
    }

    @Test
    public void getPatternExplanation()
    {
        assertSame(description, designPattern.describe());
    }
}

public interface HasDescription {
    public String describe();
}

public enum Creational implements HasDescription { /** code */ )

public enum Category implements HasDescription { /** code */ )

public enum KnownAlienRace {}