命令模式

public interface Command{
	void process(int[] target);
}
public class ProcessArray{
	public void process(int[] target,Command cmd){
		cmd.process(target);
	}
}

public class CommandTest{
	public static void main(){
		ProcessArray pa=new ProcessArray ();
		int[] target=new {1,2,3,4};
		pa.process(target,new PrintCommand());
		pa.process(target,new AddCommand());
	}
}


public class PrintCommand implements Command{
	public void process(int[] target){
		//..........
	}
}

public class AddCommand implements Command{
	public void process(int[] target){
		//..........
	}
}

通过一个command接口让ProcessArray类和具体的 “处理行为分离”，只有等到调用ProcessArray的process方法时，传入一个真正的Command实例，才确定对数组的处理行为