Generics in enums

[Victor Polischuk]

Greetings,

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>

Some time ago I wanted to migrate our "commons-lang" enums to "java 5"
enumerations, but I encountered an issue that it cannot be done without
discarding generics since java enums do not support them. Let me show an
example:

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//------

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public final class ColorEnum<T extends Pixel> extends
org.apache.commons.lang.enums.Enum {
public static final ColorEnum<PurePixel> RED = new
ColorEnum<PurePixel>("Red");
public static final ColorEnum<PurePixel> GREEN = new
ColorEnum<PurePixel>("Green");
public static final ColorEnum<PurePixel> BLUE = new
ColorEnum<PurePixel>("Blue");
public static final ColorEnum<MixedPixel> WHITE = new
ColorEnum<MixedPixel>("White") {

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@Override

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public MixedPixel make() {...} 

>

};

private ColorEnum(String color) {super(color);}

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public boolean filter(T pixel) {...}

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public T make() {...}
}

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//------

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And I wonder if there is a specific reason why I cannot convert it into
something like: 

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//------

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public enum Color<T extends Pixel> {
RED<PurePixel>("Red"),
GREEN<PurePixel>("Green"),

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BLUE <PurePixel>("Blue"),

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WHITE<MixedPixel>("White") {

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@Override

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public MixedPixel make() {...} 

> };


private Color(String color) {...}

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public boolean filter(T pixel) {...}

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>

public T make() {...}
}

> //------

Thank you in advance.

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Sincerely yours,

>

Victor Polischuk

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