제네릭

package 제네릭;

public class Generic<T> {
	private T data;
	
	public T getData() {
		return data;
	}

	public void setData(T data) {
		this.data = data;
	}
	
}

package 제네릭;

public class Generic_Test {
	public static void main(String[] args) {
		// 제네릭에서는 꼭 Wrapper클래스를 사용해야함
		Generic<String> g = new Generic<>();
		Generic<Integer> g2 = new Generic<>();
		
		g.setData("안녕");
		g2.setData(new Integer(10));
		
		System.out.println(g.getData());
		System.out.println(g2.getData());
		System.out.println(Generic_Test2.function(3.9F));
		System.out.println(Generic_Test2.function(10));
		System.out.println(Generic_Test2.function('A'));
		System.out.println(Generic_Test2.function("한동석"));
	}
}

package 제네릭;

public class Generic_Test2 {
	
	public static <T> T function(T data) {
		T result;
		if(data instanceof Integer) {
			result = (T)"정수";
		}else if (data instanceof Double || data instanceof Float) {
			result = (T) "실수";
		}else if(data instanceof Character) {
			result = (T)"문자";
		}else if(data instanceof String) {
			result = (T)"문자열";
		}else{
			result = null;
		}
		return result;
		
		}
}

package 제네릭;

public interface Ginter<N1, N2> {
	
	abstract N1 add(N1 data1, N1 data2);
	N1 sub(N1 data1, N2 data2);
	N2 mul(N2 data1, N2 data2);
	
}

package 제네릭;

public class Calc implements Ginter<Double, Integer>{

	@Override
	public Double add(Double data1, Double data2) {
		return data1 + data2;
	}

	@Override
	public Double sub(Double data1, Integer data2) {
		return data1 - data2;
	}

	@Override
	public Integer mul(Integer data1, Integer data2) {
		return data1 * data2;
	}
	
	public static void main(String[] args) {
		Calc c = new Calc();
		System.out.printf("%.2f\n", c.add(5.9, 12.23));
		System.out.printf("%.2f\n", c.sub(5.9, 12));
		System.out.printf("%.2f\n", c.mul(5,12));
		
	}
}