枚举实现单例

用枚举实现单例，方法简单、安全。值得学习

enum Singleton {
	RED(255, 0, 0), GREEN(0, 255, 0), BLUE(0, 0, 255);

	// 构造枚举值
	Singleton(int rv, int gv, int bv) {
		this.redValue = rv;
		this.greenValue = gv;
		this.blueValue = bv;
	}

	// 自定义数据域，private为了封装。
	private int redValue;
	private int greenValue;
	private int blueValue;

	public int getRedValue() {
		return redValue;
	}

	public void setRedValue(int redValue) {
		this.redValue = redValue;
	}

	public int getGreenValue() {
		return greenValue;
	}

	public void setGreenValue(int greenValue) {
		this.greenValue = greenValue;
	}

	public int getBlueValue() {
		return blueValue;
	}

	public void setBlueValue(int blueValue) {
		this.blueValue = blueValue;
	}
}

public class Demo {
	public static void main(String[] args) {
		System.out.println(Singleton.RED.getRedValue());
	}
}